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Publisher: Oxford University Press   (Total: 369 journals)

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Showing 1 - 200 of 369 Journals sorted alphabetically
Acta Biochimica et Biophysica Sinica     Hybrid Journal   (Followers: 6, SJR: 0.881, h-index: 38)
Adaptation     Hybrid Journal   (Followers: 8, SJR: 0.111, h-index: 4)
Aesthetic Surgery J.     Hybrid Journal   (Followers: 6, SJR: 1.538, h-index: 35)
African Affairs     Hybrid Journal   (Followers: 57, SJR: 1.512, h-index: 46)
Age and Ageing     Hybrid Journal   (Followers: 79, SJR: 1.611, h-index: 107)
Alcohol and Alcoholism     Hybrid Journal   (Followers: 14, SJR: 0.935, h-index: 80)
American Entomologist     Full-text available via subscription   (Followers: 5)
American Historical Review     Hybrid Journal   (Followers: 120, SJR: 0.652, h-index: 43)
American J. of Agricultural Economics     Hybrid Journal   (Followers: 41, SJR: 1.441, h-index: 77)
American J. of Epidemiology     Hybrid Journal   (Followers: 146, SJR: 3.047, h-index: 201)
American J. of Hypertension     Hybrid Journal   (Followers: 19, SJR: 1.397, h-index: 111)
American J. of Jurisprudence     Hybrid Journal   (Followers: 15)
American journal of legal history     Full-text available via subscription   (Followers: 4, SJR: 0.151, h-index: 7)
American Law and Economics Review     Hybrid Journal   (Followers: 26, SJR: 0.824, h-index: 23)
American Literary History     Hybrid Journal   (Followers: 12, SJR: 0.185, h-index: 22)
Analysis     Hybrid Journal   (Followers: 23)
Annals of Botany     Hybrid Journal   (Followers: 33, SJR: 1.912, h-index: 124)
Annals of Occupational Hygiene     Hybrid Journal   (Followers: 24, SJR: 0.837, h-index: 57)
Annals of Oncology     Hybrid Journal   (Followers: 48, SJR: 4.362, h-index: 173)
Annals of the Entomological Society of America     Full-text available via subscription   (Followers: 9, SJR: 0.642, h-index: 53)
Annals of Work Exposures and Health     Hybrid Journal  
AoB Plants     Open Access   (Followers: 4, SJR: 0.78, h-index: 10)
Applied Economic Perspectives and Policy     Hybrid Journal   (Followers: 18, SJR: 0.884, h-index: 31)
Applied Linguistics     Hybrid Journal   (Followers: 51, SJR: 1.749, h-index: 63)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1, SJR: 0.779, h-index: 11)
Arbitration Intl.     Full-text available via subscription   (Followers: 19)
Arbitration Law Reports and Review     Hybrid Journal   (Followers: 12)
Archives of Clinical Neuropsychology     Hybrid Journal   (Followers: 25, SJR: 0.96, h-index: 71)
Aristotelian Society Supplementary Volume     Hybrid Journal   (Followers: 2, SJR: 0.102, h-index: 20)
Arthropod Management Tests     Hybrid Journal   (Followers: 2)
Astronomy & Geophysics     Hybrid Journal   (Followers: 46, SJR: 0.144, h-index: 15)
Behavioral Ecology     Hybrid Journal   (Followers: 47, SJR: 1.698, h-index: 92)
Bioinformatics     Hybrid Journal   (Followers: 222, SJR: 4.643, h-index: 271)
Biology Methods and Protocols     Hybrid Journal  
Biology of Reproduction     Full-text available via subscription   (Followers: 10, SJR: 1.646, h-index: 149)
Biometrika     Hybrid Journal   (Followers: 18, SJR: 2.801, h-index: 90)
BioScience     Hybrid Journal   (Followers: 28, SJR: 2.374, h-index: 154)
Bioscience Horizons : The National Undergraduate Research J.     Open Access   (Followers: 1, SJR: 0.213, h-index: 9)
Biostatistics     Hybrid Journal   (Followers: 15, SJR: 1.955, h-index: 55)
BJA : British J. of Anaesthesia     Hybrid Journal   (Followers: 132, SJR: 2.314, h-index: 133)
BJA Education     Hybrid Journal   (Followers: 65, SJR: 0.272, h-index: 20)
Brain     Hybrid Journal   (Followers: 61, SJR: 6.097, h-index: 264)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 43, SJR: 4.086, h-index: 73)
Briefings in Functional Genomics     Hybrid Journal   (Followers: 4, SJR: 1.771, h-index: 50)
British J. for the Philosophy of Science     Hybrid Journal   (Followers: 32, SJR: 1.267, h-index: 38)
British J. of Aesthetics     Hybrid Journal   (Followers: 24, SJR: 0.217, h-index: 18)
British J. of Criminology     Hybrid Journal   (Followers: 489, SJR: 1.373, h-index: 62)
British J. of Social Work     Hybrid Journal   (Followers: 77, SJR: 0.771, h-index: 53)
British Medical Bulletin     Hybrid Journal   (Followers: 7, SJR: 1.391, h-index: 84)
British Yearbook of Intl. Law     Hybrid Journal   (Followers: 26)
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 3, SJR: 1.474, h-index: 31)
Cambridge J. of Economics     Hybrid Journal   (Followers: 55, SJR: 0.957, h-index: 59)
Cambridge J. of Regions, Economy and Society     Hybrid Journal   (Followers: 9, SJR: 1.067, h-index: 22)
Cambridge Quarterly     Hybrid Journal   (Followers: 10, SJR: 0.1, h-index: 7)
Capital Markets Law J.     Hybrid Journal  
Carcinogenesis     Hybrid Journal   (Followers: 2, SJR: 2.439, h-index: 167)
Cardiovascular Research     Hybrid Journal   (Followers: 11, SJR: 2.897, h-index: 175)
Cerebral Cortex     Hybrid Journal   (Followers: 37, SJR: 4.827, h-index: 192)
CESifo Economic Studies     Hybrid Journal   (Followers: 15, SJR: 0.501, h-index: 19)
Chemical Senses     Hybrid Journal   (Followers: 1, SJR: 1.436, h-index: 76)
Children and Schools     Hybrid Journal   (Followers: 5, SJR: 0.211, h-index: 18)
Chinese J. of Comparative Law     Hybrid Journal   (Followers: 3)
Chinese J. of Intl. Law     Hybrid Journal   (Followers: 19, SJR: 0.737, h-index: 11)
Chinese J. of Intl. Politics     Hybrid Journal   (Followers: 8, SJR: 1.238, h-index: 15)
Christian Bioethics: Non-Ecumenical Studies in Medical Morality     Hybrid Journal   (Followers: 11, SJR: 0.191, h-index: 8)
Classical Receptions J.     Hybrid Journal   (Followers: 17, SJR: 0.1, h-index: 3)
Clinical Infectious Diseases     Hybrid Journal   (Followers: 58, SJR: 4.742, h-index: 261)
Clinical Kidney J.     Open Access   (Followers: 4, SJR: 0.338, h-index: 19)
Community Development J.     Hybrid Journal   (Followers: 23, SJR: 0.47, h-index: 28)
Computer J.     Hybrid Journal   (Followers: 8, SJR: 0.371, h-index: 47)
Conservation Physiology     Open Access   (Followers: 1)
Contemporary Women's Writing     Hybrid Journal   (Followers: 11, SJR: 0.111, h-index: 3)
Contributions to Political Economy     Hybrid Journal   (Followers: 6, SJR: 0.313, h-index: 10)
Critical Values     Full-text available via subscription  
Current Legal Problems     Hybrid Journal   (Followers: 25)
Current Zoology     Full-text available via subscription   (SJR: 0.999, h-index: 20)
Database : The J. of Biological Databases and Curation     Open Access   (Followers: 11, SJR: 1.068, h-index: 24)
Digital Scholarship in the Humanities     Hybrid Journal   (Followers: 12)
Diplomatic History     Hybrid Journal   (Followers: 18, SJR: 0.296, h-index: 22)
DNA Research     Open Access   (Followers: 4, SJR: 2.42, h-index: 77)
Dynamics and Statistics of the Climate System     Open Access   (Followers: 2)
Early Music     Hybrid Journal   (Followers: 13, SJR: 0.124, h-index: 11)
Economic Policy     Hybrid Journal   (Followers: 47, SJR: 2.052, h-index: 52)
ELT J.     Hybrid Journal   (Followers: 25, SJR: 1.26, h-index: 23)
English Historical Review     Hybrid Journal   (Followers: 45, SJR: 0.311, h-index: 10)
English: J. of the English Association     Hybrid Journal   (Followers: 12, SJR: 0.144, h-index: 3)
Environmental Entomology     Full-text available via subscription   (Followers: 11, SJR: 0.791, h-index: 66)
Environmental Epigenetics     Open Access   (Followers: 1)
Environmental History     Hybrid Journal   (Followers: 25, SJR: 0.197, h-index: 25)
EP-Europace     Hybrid Journal   (Followers: 1, SJR: 2.201, h-index: 71)
Epidemiologic Reviews     Hybrid Journal   (Followers: 9, SJR: 3.917, h-index: 81)
ESHRE Monographs     Hybrid Journal  
Essays in Criticism     Hybrid Journal   (Followers: 15, SJR: 0.1, h-index: 6)
European Heart J.     Hybrid Journal   (Followers: 46, SJR: 6.997, h-index: 227)
European Heart J. - Cardiovascular Imaging     Hybrid Journal   (Followers: 9, SJR: 2.044, h-index: 58)
European Heart J. - Cardiovascular Pharmacotherapy     Full-text available via subscription   (Followers: 1)
European Heart J. - Quality of Care and Clinical Outcomes     Hybrid Journal  
European Heart J. Supplements     Hybrid Journal   (Followers: 8, SJR: 0.152, h-index: 31)
European J. of Cardio-Thoracic Surgery     Hybrid Journal   (Followers: 7, SJR: 1.568, h-index: 104)
European J. of Intl. Law     Hybrid Journal   (Followers: 141, SJR: 0.722, h-index: 38)
European J. of Orthodontics     Hybrid Journal   (Followers: 4, SJR: 1.09, h-index: 60)
European J. of Public Health     Hybrid Journal   (Followers: 22, SJR: 1.284, h-index: 64)
European Review of Agricultural Economics     Hybrid Journal   (Followers: 12, SJR: 1.549, h-index: 42)
European Review of Economic History     Hybrid Journal   (Followers: 25, SJR: 0.628, h-index: 24)
European Sociological Review     Hybrid Journal   (Followers: 37, SJR: 2.061, h-index: 53)
Evolution, Medicine, and Public Health     Open Access   (Followers: 11)
Family Practice     Hybrid Journal   (Followers: 13, SJR: 1.048, h-index: 77)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 8, SJR: 1.687, h-index: 115)
Fems Microbiology Letters     Hybrid Journal   (Followers: 19, SJR: 1.126, h-index: 118)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 24, SJR: 7.587, h-index: 150)
Fems Yeast Research     Hybrid Journal   (Followers: 13, SJR: 1.213, h-index: 66)
Foreign Policy Analysis     Hybrid Journal   (Followers: 21, SJR: 0.859, h-index: 10)
Forestry: An Intl. J. of Forest Research     Hybrid Journal   (Followers: 17, SJR: 0.903, h-index: 44)
Forum for Modern Language Studies     Hybrid Journal   (Followers: 6, SJR: 0.108, h-index: 6)
French History     Hybrid Journal   (Followers: 29, SJR: 0.123, h-index: 10)
French Studies     Hybrid Journal   (Followers: 19, SJR: 0.119, h-index: 7)
French Studies Bulletin     Hybrid Journal   (Followers: 10, SJR: 0.102, h-index: 3)
Gastroenterology Report     Open Access   (Followers: 2)
Genome Biology and Evolution     Open Access   (Followers: 10, SJR: 3.22, h-index: 39)
Geophysical J. Intl.     Hybrid Journal   (Followers: 31, SJR: 1.839, h-index: 119)
German History     Hybrid Journal   (Followers: 24, SJR: 0.437, h-index: 13)
GigaScience     Open Access   (Followers: 3)
Global Summitry     Hybrid Journal  
Glycobiology     Hybrid Journal   (Followers: 14, SJR: 1.692, h-index: 101)
Health and Social Work     Hybrid Journal   (Followers: 46, SJR: 0.505, h-index: 40)
Health Education Research     Hybrid Journal   (Followers: 12, SJR: 0.814, h-index: 80)
Health Policy and Planning     Hybrid Journal   (Followers: 21, SJR: 1.628, h-index: 66)
Health Promotion Intl.     Hybrid Journal   (Followers: 19, SJR: 0.664, h-index: 60)
History Workshop J.     Hybrid Journal   (Followers: 25, SJR: 0.313, h-index: 20)
Holocaust and Genocide Studies     Hybrid Journal   (Followers: 22, SJR: 0.115, h-index: 13)
Human Molecular Genetics     Hybrid Journal   (Followers: 10, SJR: 4.288, h-index: 233)
Human Reproduction     Hybrid Journal   (Followers: 74, SJR: 2.271, h-index: 179)
Human Reproduction Update     Hybrid Journal   (Followers: 15, SJR: 4.678, h-index: 128)
Human Rights Law Review     Hybrid Journal   (Followers: 60, SJR: 0.7, h-index: 21)
ICES J. of Marine Science: J. du Conseil     Hybrid Journal   (Followers: 53, SJR: 1.233, h-index: 88)
ICSID Review     Hybrid Journal   (Followers: 8)
ILAR J.     Hybrid Journal   (Followers: 1, SJR: 1.099, h-index: 51)
IMA J. of Applied Mathematics     Hybrid Journal   (SJR: 0.329, h-index: 26)
IMA J. of Management Mathematics     Hybrid Journal   (Followers: 2, SJR: 0.351, h-index: 20)
IMA J. of Mathematical Control and Information     Hybrid Journal   (Followers: 2, SJR: 0.661, h-index: 28)
IMA J. of Numerical Analysis - advance access     Hybrid Journal   (SJR: 2.032, h-index: 44)
Industrial and Corporate Change     Hybrid Journal   (Followers: 8, SJR: 1.37, h-index: 81)
Industrial Law J.     Hybrid Journal   (Followers: 29, SJR: 0.184, h-index: 15)
Information and Inference     Free  
Integrative and Comparative Biology     Hybrid Journal   (Followers: 7, SJR: 1.911, h-index: 90)
Interacting with Computers     Hybrid Journal   (Followers: 10, SJR: 0.529, h-index: 59)
Interactive CardioVascular and Thoracic Surgery     Hybrid Journal   (Followers: 4, SJR: 0.743, h-index: 35)
Intl. Data Privacy Law     Hybrid Journal   (Followers: 27)
Intl. Health     Hybrid Journal   (Followers: 4, SJR: 0.835, h-index: 15)
Intl. Immunology     Hybrid Journal   (Followers: 4, SJR: 1.613, h-index: 111)
Intl. J. for Quality in Health Care     Hybrid Journal   (Followers: 32, SJR: 1.593, h-index: 69)
Intl. J. of Constitutional Law     Hybrid Journal   (Followers: 50, SJR: 0.613, h-index: 19)
Intl. J. of Epidemiology     Hybrid Journal   (Followers: 115, SJR: 4.381, h-index: 145)
Intl. J. of Law and Information Technology     Hybrid Journal   (Followers: 3, SJR: 0.247, h-index: 8)
Intl. J. of Law, Policy and the Family     Hybrid Journal   (Followers: 18, SJR: 0.307, h-index: 15)
Intl. J. of Lexicography     Hybrid Journal   (Followers: 8, SJR: 0.404, h-index: 18)
Intl. J. of Low-Carbon Technologies     Open Access   (Followers: 1, SJR: 0.457, h-index: 12)
Intl. J. of Neuropsychopharmacology     Open Access   (Followers: 4, SJR: 1.69, h-index: 79)
Intl. J. of Public Opinion Research     Hybrid Journal   (Followers: 8, SJR: 0.906, h-index: 33)
Intl. J. of Refugee Law     Hybrid Journal   (Followers: 34, SJR: 0.231, h-index: 21)
Intl. J. of Transitional Justice     Hybrid Journal   (Followers: 13, SJR: 0.833, h-index: 12)
Intl. Mathematics Research Notices     Hybrid Journal   (Followers: 1, SJR: 2.052, h-index: 42)
Intl. Mathematics Research Surveys - advance access     Hybrid Journal  
Intl. Political Sociology     Hybrid Journal   (Followers: 24, SJR: 1.339, h-index: 19)
Intl. Relations of the Asia-Pacific     Hybrid Journal   (Followers: 17, SJR: 0.539, h-index: 17)
Intl. Studies Perspectives     Hybrid Journal   (Followers: 7, SJR: 0.998, h-index: 28)
Intl. Studies Quarterly     Hybrid Journal   (Followers: 33, SJR: 2.184, h-index: 68)
Intl. Studies Review     Hybrid Journal   (Followers: 17, SJR: 0.783, h-index: 38)
ISLE: Interdisciplinary Studies in Literature and Environment     Hybrid Journal   (Followers: 1, SJR: 0.155, h-index: 4)
ITNOW     Hybrid Journal   (Followers: 2, SJR: 0.102, h-index: 4)
J. of African Economies     Hybrid Journal   (Followers: 15, SJR: 0.647, h-index: 30)
J. of American History     Hybrid Journal   (Followers: 38, SJR: 0.286, h-index: 34)
J. of Analytical Toxicology     Hybrid Journal   (Followers: 13, SJR: 1.038, h-index: 60)
J. of Antimicrobial Chemotherapy     Hybrid Journal   (Followers: 20, SJR: 2.157, h-index: 149)
J. of Antitrust Enforcement     Hybrid Journal   (Followers: 1)
J. of Applied Poultry Research     Hybrid Journal   (Followers: 3, SJR: 0.563, h-index: 43)
J. of Biochemistry     Hybrid Journal   (Followers: 43, SJR: 1.341, h-index: 96)
J. of Chromatographic Science     Hybrid Journal   (Followers: 18, SJR: 0.448, h-index: 42)
J. of Church and State     Hybrid Journal   (Followers: 11, SJR: 0.167, h-index: 11)
J. of Competition Law and Economics     Hybrid Journal   (Followers: 34, SJR: 0.442, h-index: 16)
J. of Complex Networks     Hybrid Journal   (Followers: 1, SJR: 1.165, h-index: 5)
J. of Conflict and Security Law     Hybrid Journal   (Followers: 11, SJR: 0.196, h-index: 15)
J. of Consumer Research     Full-text available via subscription   (Followers: 38, SJR: 4.896, h-index: 121)
J. of Crohn's and Colitis     Hybrid Journal   (Followers: 9, SJR: 1.543, h-index: 37)
J. of Cybersecurity     Hybrid Journal   (Followers: 2)
J. of Deaf Studies and Deaf Education     Hybrid Journal   (Followers: 8, SJR: 0.69, h-index: 36)
J. of Design History     Hybrid Journal   (Followers: 15, SJR: 0.166, h-index: 14)
J. of Economic Entomology     Full-text available via subscription   (Followers: 6, SJR: 0.894, h-index: 76)
J. of Economic Geography     Hybrid Journal   (Followers: 32, SJR: 2.909, h-index: 69)
J. of Environmental Law     Hybrid Journal   (Followers: 25, SJR: 0.457, h-index: 20)
J. of European Competition Law & Practice     Hybrid Journal   (Followers: 19)
J. of Experimental Botany     Hybrid Journal   (Followers: 13, SJR: 2.798, h-index: 163)
J. of Financial Econometrics     Hybrid Journal   (Followers: 21, SJR: 1.314, h-index: 27)
J. of Global Security Studies     Hybrid Journal   (Followers: 2)
J. of Heredity     Hybrid Journal   (Followers: 3, SJR: 1.024, h-index: 76)
J. of Hindu Studies     Hybrid Journal   (Followers: 7, SJR: 0.186, h-index: 3)
J. of Hip Preservation Surgery     Open Access  
J. of Human Rights Practice     Hybrid Journal   (Followers: 21, SJR: 0.399, h-index: 10)
J. of Infectious Diseases     Hybrid Journal   (Followers: 39, SJR: 4, h-index: 209)
J. of Insect Science     Open Access   (Followers: 9, SJR: 0.388, h-index: 31)

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Journal Cover ICES Journal of Marine Science: Journal du Conseil
  [SJR: 1.233]   [H-I: 88]   [53 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1054-3139 - ISSN (Online) 1095-9289
   Published by Oxford University Press Homepage  [369 journals]
  • Quo Vadimus—Redux
    • Authors: Browman HI.
      Abstract: The ICES Journal of Marine Science has been published continuously since 1903, albeit under several different names, making it one of the oldest marine science journals (Anderson, 2012). The Journal has had a series of accomplished Editors-in-Chief (EiC). I have held that role since 2012 (Browman, 2012), and will continue for a second 5-year term, through 2021. My purpose here is to recount how the Journal has developed during my first term as EiC, and to lay out where we are headed in the next 5 years.
      PubDate: 2017-02-02
       
  • Operationalizing and implementing ecosystem-based management
    • Authors: Link JS; Browman HI.
      Abstract: There is now a large literature on ecosystem-based management (EBM; also known as the ecosystem approach). Our sense is that EBM is moving - albeit slowly - from the “what's, why's and when's” to the “how's” of operationalization and implementation; as such it seemed timely to develop this article theme set (TS). Our objectives were to ascertain the state of the discipline and to advance EBM by offering practical examples of its implementation - or attempts at such - in a variety of incarnations and at various scales, including what has or has not worked, suggestions for best practice, and lessons learned. As exemplified by the articles in this TS, key lessons learned include the need for: constant and clear communication with all parties involved; clear objectives and governance; the distillation of complex ecosystem information into digestible indicators; the establishment of reference levels on which management decisions can be made; and clear protocols to evaluate tradeoffs. Instances of truly multisectoral EBM remain rare, with EBM having advanced farthest within specific ocean-use sectors. Although progress towards implementing operational EBM has been somewhat limited, and although EBM is by its very nature complex and difficult to operationalize, there has been progress nonetheless. We hope that this TS will encourage even further operationalization of EBM.
      PubDate: 2017-02-02
       
  • An approach for effective stakeholder engagement as an essential component
           of the ecosystem approach
    • Authors: Oates J; Dodds LA, .
      Abstract: Effective stakeholder engagement is an essential, but commonly overlooked, component of the ecosystem approach. In this article, we draw lessons from two European Union LIFE+ (LIFE is the European Union's financial instrument supporting environmental, nature conservation and climate action projects throughout the EU.) funded projects led by WWF-UK: PISCES (Partnerships Involving Stakeholders in the Celtic sea EcoSystem) and the Celtic Seas Partnership to present an approach for effective stakeholder engagement. These projects developed steps to operationalise the ecosystem approach within the context of a key piece of European legislation: the Marine Strategy Framework Directive (MSFD, 2008/56/EC).We identified an approach for involving stakeholders in delivery of the ecosystem approach, which can be applied to other areas and contexts. The approach involves four steps: Identify a relevant policy framework and the role of stakeholders in its implementation and identify or agree environmental, social and economic objectives for the area.Create an open, neutral, cross-sectoral forum and design an engagement process that creates a “safe” and inclusive space, and is facilitated independently.Demystify terminology and develop a shared vision or principles through an engagement processCollaboratively develop management actions that are needed to achieve objectives and implement them.
      PubDate: 2017-02-02
       
  • Tinkering with a tanker—slow evolution of a Swedish ecosystem
           approach
    • Authors: Österblom H; Hentati-Sundberg J, Nevonen N, et al.
      Abstract: The ecosystem approach is a salient policy paradigm originating from a scientific understanding of the reality of complex ecosystem dynamics. In this article, we investigate how Swedish national marine policies and practice between 2002 and 2015 have changed towards an ecosystem approach. Government documents, the scientific literature, institutional changes, changes in legislation, pilot projects, and changes in science and public opinion were reviewed and combined with information from expert interviews. We found that changes in policy and practice have slowly stimulated the development of an ecosystem approach, but that limited political leadership, challenges of coordination, different agency cultures, and limited learning appears to be key barriers for further and more substantial change. We compare and contrast the Swedish national process of change with other documented experiences of implementing an ecosystem approach and find that several countries struggle with similar challenges. Substantial work still remains in Sweden and we provide suggestions for how to stimulate further and more substantial change at the national level.
      PubDate: 2017-02-02
       
  • ecosystem-based management’?>A continuous involvement of stakeholders
           promotes the ecosystem approach to fisheries in the 8-fjords area on the
           Swedish west coast
    • Authors: Bryhn AC; Lundström K, Johansson A, et al.
      Abstract: The coastal marine environment in the 8-fjords area on the Swedish west coast has been subjected to various stakeholder co-management initiatives since 1999. Stakeholders and authorities have acted by supporting and implementing gradually stricter fishing restrictions following the collapse in the 1970s of several demersal fish stocks and their apparent lack of recovery. Moreover, concerns have been raised regarding a locally sharp depletion of eelgrass meadows, in addition to an apparent increase in the number of seals and cormorants. The present 8-fjords initiative applies a cross-sector approach to environmental management and thus also addresses various types of environmental pollution. This study has compared the environmental work around the 8-fjords to 15 principles regarding the ecosystem approach to fisheries (EAF). The main strength that has been identified among the EAF principles is the continuous involvement of stakeholders. Among weaknesses in the EAF is the scarcity of suitable indicators that are necessary for appropriate monitoring, especially biomasses of functional groups as well as economic and social indicators. Many environmental problems in the fjords remain and it is possible that improved adherence to EAF principles will facilitate solving some problems and alleviating others. Moreover, the application of the EAF in practice in the 8-fjords can serve as a guiding example for co-managing other aquatic ecosystems towards ecological, economic, and social sustainability. The experiences from the 8-fjords initiative, including its extensive stakeholder involvement, may serve as a practical EAF example to be studied by researchers and managers globally.
      PubDate: 2016-12-23
       
  • Implementing “the IEA”: using integrated ecosystem assessment
           frameworks, programs, and applications in support of operationalizing
           ecosystem-based management
    • Authors: Harvey CJ; Kelble CR, Schwing FB, et al.
      Abstract: The Integrated Ecosystem Assessment (IEA) approach was designed to assimilate scientific knowledge in the ideal format for providing advice to inform marine Ecosystem-Based Management (EBM). As such, IEAs were envisioned as the cornerstone integrated science product for the US National Oceanic and Atmospheric Administration (NOAA) that would maximize efficiencies and synergies across the agency’s ecosystem science efforts. This led to the development of a NOAA IEA Program that would oversee regional implementation of the national IEA framework. As implementation proceeded, uptake by management entities was slower than anticipated, in part because EBM was not quickly embraced and applied to achieve management objectives. This slow movement to EBM in conjunction with the need to develop scientific analyses and methods to properly implement IEA resulted in the IEA process being viewed as its own endpoint. This commonly led to referring to “the IEA” when variously discussing the IEA framework, program, products, and process. Now that IEA and EBM are maturing, we need to be specific with what we are referring to when discussing IEAs, in order to develop reasonable expectations for applying IEA tools. We also now recognize the need to implement multiple IEA processes at varying geographic and complexity scales within an ecosystem to effectively meet the scientific requirements for operational EBM rather than viewing an IEA application as a single regional science product.
      PubDate: 2016-12-13
       
  • International perceptions of an integrated, multi-sectoral, ecosystem
           approach to management
    • Authors: Marshak AR; Link JS, Shuford R, et al.
      Abstract: The Ecosystem Approach to Management (EAM) has emerged over the past decades, largely to promote biodiversity conservation, and more recently sectoral tradeoffs in the management of marine ecosystems. To ascertain the state of practice of EAM operationalization, a workshop was held, which included a pre-workshop online survey. The survey gauged international participants’ perspectives regarding capacity, knowledge, and application of EAM. When asked about the subject, most survey respondents had a general understanding of EAM, and provided a clear definition. Major perceived challenges to EAM objectives by those surveyed included limited knowledge, conflicting interests, insufficient communication, and limited organizational legal frameworks or governance structures. Of those directly involved in an ecosystem approach, the majority responded that processes were in place or developed for application of integrated knowledge toward assessing key issues within their respective sectors (i.e. fisheries, conservation, energy), and that capacity was generally high. Our results show that most respondents, irrespective of sector or geography, see value in considering an integrated, broader ecosystem approach as they manage their sector. Although many participants were from the North Atlantic region, our results suggest that much of the international community is converging toward continued understanding of broad-scale, integrated approaches to marine resource management.
      PubDate: 2016-12-09
       
  • Shark finning in eastern Indonesia: assessing the sustainability of a
           data-poor fishery
    • Authors: Jaiteh VF; Hordyk AR, Braccini M, et al.
      Abstract: For over two decades, Indonesia has reported higher average shark landings than any other nation, but very little local information exists on the fishery and life histories of targeted species. This poses severe challenges to shark sustainability and conservation in this vast archipelago. We draw on diverse sources of data to evaluate the sustainability of the shark fishery in eastern Indonesia, a particularly data-poor region where sharks are primarily targeted for their fins. Shark fishers from three coastal communities were interviewed on their perceptions of catch trends over the past twenty years and asked to collect fishing data during fishing trips in the Seram, Arafura and Timor Seas. For the most frequently harvested species, we estimated maximum intrinsic rates of increase (rmax) to predict their resilience to fishing pressure. Our results indicate that shark fishing practices in the region are likely to be unsustainable. The catches of several species largely comprised of immature individuals and most fishers attributed observed declines in shark numbers, size and species diversity to overfishing. Hammerhead sharks have relatively high intrinsic resilience but are nevertheless at risk of local extinction due to their availability to the fishery and the value of their fins. Sandbar, dusky and grey reef sharks have lower resilience and are frequently caught but not managed. We recommend a composite management approach, including consistent implementation of existing trade restrictions, fisheries research and opportunities for fishers’ livelihood diversification, to stem shark harvests in eastern Indonesia.
      PubDate: 2016-11-07
       
  • Eastern Baltic cod recruitment revisited—dynamics and impacting
           factors
    • Authors: Köster FW; Huwer B, Hinrichsen H, et al.
      Abstract: The Eastern Baltic cod abundance started rapidly to increase in the mid-2000s as evidenced by analytical stock assessments, due to increased recruitment and declining fishing mortality. Since 2014, the analytical stock assessment is not available, leaving the present stock status unclear and casting doubts about the magnitude of the recent increase in recruitment. Earlier studies identified main factors impacting on cod reproductive success to be related to the loss of two out of three spawning areas in the 1980s caused by lack of major Baltic inflows with a concurrent reduction in salinity and oxygen. Other important factors include prey availability for first-feeding larvae, egg predation by sprat and herring and cannibalism on juveniles, all in one way or the other related to the prevailing hydrographic conditions. These factors cannot explain increased reproductive success in the last decade, as the period was characterized by an absence of large-scale Baltic inflows since 2003 and persistent anoxic conditions in the bottom water of the deep Baltic basins. This questions the perception of the increased recruitment in later years and challenges our present understanding of cod recruitment dynamics in the Baltic Sea. In this contribution, we review evidence from the recent literature supplemented by information from latest research cruises to elucidate whether cod reproductive success indeed has increased during the last decade, and we suggest the key processes responsible for the recent dynamics in cod recruitment and outline directions for future research.
      PubDate: 2016-10-27
       
  • Massive increase in the use of drifting Fish Aggregating Devices (dFADs)
           by tropical tuna purse seine fisheries in the Atlantic and Indian oceans
    • Authors: Maufroy A; Kaplan DM, Bez N, et al.
      Abstract: Since the mid-1990s, drifting Fish Aggregating Devices (dFADs), artificial floating objects designed to aggregate fish, have become an important mean by which purse seine fleets catch tropical tunas. Mass deployment of dFADs, as well as the massive use of GPS buoys to track dFADs and natural floating objects, has raised serious concerns for the state of tropical tuna stocks and ecosystem functioning. Here, we combine tracks from a large proportion of the French GPS buoys from the Indian and Atlantic oceans with data from observers aboard French and Spanish purse seiners and French logbook data to estimate the total number of dFADs and GPS buoys used within the main fishing grounds of these two oceans over the period 2007–2013. In the Atlantic Ocean, the total number of dFADs increased from 1175 dFADs active in January 2007 to 8575 dFADs in August 2013. In the Indian Ocean, this number increased from 2250 dFADs in October 2007 to 10 300 dFADs in September 2013. In both oceans, at least a fourfold increase in the number of dFADs was observed over the 7-year study period. Though the relative proportion of natural to artificial floating objects varied over space, with some areas such as the Mozambique Channel and areas adjacent to the mouths of the Niger and Congo rivers being characterized by a relatively high percentage of natural objects, in no region do dFADs represent
      PubDate: 2016-10-26
       
  • Extraction of microplastic from biota: recommended acidic digestion
           destroys common plastic polymers
    • Authors: Enders K; Lenz R, Beer S, et al.
      Abstract: The chemical digestion of tissue from marine biota for microplastic analysis is currently conducted following a variety of protocols published in scientific literature. Often there is a lack of information on whether and to which degree the applied chemicals are destructive to microplastic particles of various polymer types. In the present study we report that a digestion protocol recently recommended by ICES using nitric and perchloric acid has strong detrimental effects on several common plastic polymers, in particular polyamide and polyurethane and to a lesser degree acrylonitrile butadiene styrene, polymethyl methacrylate and polyvinylchloride. Raman spectroscopic measurements revealed changes in peak occurrence and intensity for several polymers that did not otherwise show visual macroscopic changes. We developed and tested an alkaline digestion protocol in order to preserve small microplastic particles while removing organic tissue material. We recommend this method for the development of guidelines for plastic microplastic monitoring in biota.
      PubDate: 2016-10-26
       
  • Moving from ecosystem-based policy objectives to operational
           implementation of ecosystem-based management measures
    • Authors: Cormier R; Kelble CR, Anderson M, et al.
      Abstract: The aim of ecosystem-based management (EBM) is to maintain an ecosystem in a healthy, productive and resilient condition through the implementation of policies and management measures. Although cross-sectoral planning may be led by a planning competent authority, it is up to the sector competent authority to implement the necessary management measures within their operations to achieve EBM goals and objectives. We suggest that scientific impediments to EBM are no longer significant to implement EBM operationally. Instead, we consider that approaching EBM within current policy cycle approaches would provide the necessary policymaking process step to operationalize EBM. In addition to enabling and facilitating collaboration, exchange, understanding as promoted by EBM, policymaking processes also require that policy is to be implemented through programs, measures, procedures and controls that have expected outcomes to “carry into effect” the policy objective. We are of the view that moving EBM from planning and objective setting to operational implementation is a management problem solving issues instead of a scientific one.
      PubDate: 2016-10-25
       
  • Survival and dispersal variability of pelagic eggs and yolk-sac larvae of
           central and eastern baltic flounder ( Platichthys flesus ): application of
           biophysical models
    • Authors: Hinrichsen H; Petereit C, Nissling A, et al.
      Abstract: A hydrodynamic model coupled with a Lagrangian particle tracking technique was utilized to simulate spatially and temporally resolved long-term environmentally related (i) size of habitat suitable for reproduction, (ii) egg/yolk-sac larval survival, (iii) separation of causes of mortality, and (iv) connectivity between spawning areas of Baltic flounder with pelagic eggs. Information on reproduction habitat requirements and mortality sources were obtained from field or laboratory studies. In our modelling study we only quantified physical processes generating heterogeneity in spatial distribution of eggs and yolk-sac larvae, as e.g. predation is not accounted for. The spatial extent of eggs and larvae represented as modelled particles is primarily determined by oxygen and salinity conditions. The reproduction habitat most suitable was determined for the Gdansk Deep, followed by the Bornholm Basin. Relatively low habitat suitability was obtained for the Arkona Basin and the Gotland Basin. The model runs also showed yolk-sac larval survival to be to a large extent affected by sedimentation. Eggs initially released in the Arkona Basin and Bornholm Basin are strongly affected by sedimentation compared with those released in the Gdansk Deep and Gotland Basin. Highest relative survival of eggs occurred in the Gdansk Deep and in the Bornholm Basin. Relatively low survival rates in the Gotland Basin were attributable to oxygen-dependent mortality. Oxygen content had almost no impact on survival in the Arkona Basin. For all spawning areas mortality caused by lethally low temperatures was only evident after severe winters. Buoyancy of eggs and yolk-sac larvae in relation to topographic features appear as a barrier for the transport of eggs and yolk-sac larvae and potentially limits the connectivity of early life stages between the different spawning areas.
      PubDate: 2016-10-25
       
  • Reconstruction of global ex-vessel prices of fished species
    • Authors: Melnychuk MC; Clavelle T, Owashi B, et al.
      Abstract: Economic dimensions of global fishery analyses are often limited by unavailable or inconsistent ex-vessel price data from the world’s fishing nations. We describe a novel method for estimating ex-vessel price time series for individual species by converting export prices of fishery commodities into ex-vessel prices and pairing these with species. The method relies exclusively on global, publicly-available data from the Food and Agricultural Organization of the United Nations (FAO). National datasets of ex-vessel prices are not used as inputs for the method, but comparisons of reconstructed ex-vessel prices with actual prices from national datasets showed strong correspondence. Correlation coefficients for paired reconstructed prices and actual prices of the same species were typically between 0.60 and 0.75 annually in the past two decades. There was a tendency for reconstructed prices to be less variable than actual prices, over-estimating actual prices at low values of actual prices and under-estimating actual prices at high values, likely the result of incomplete price transmission or assigning a given price time series to multiple species. However, there was no evidence of overall bias between reconstructed prices and actual prices, and correlations were strongest for comparisons involving multiple taxonomic groups. The method described carries advantages of global comprehensiveness and consistency across countries in reconstructed ex-vessel prices, reflecting the comprehensiveness and consistency of export price information. The method described links to species from the global FAO landings database, but can be modified to pair with other species lists or to focus on specific regions or countries. Data tables and source code are publicly available and ex-vessel price estimates can be updated annually following annual releases of the FAO fishery commodities database.
      PubDate: 2016-10-21
       
  • The ecosystem approach in the Gulf of Cadiz. A perspective from the
           southernmost European Atlantic regional sea
    • Authors: Llope M; .
      Abstract: This article considers the major events in recent history, current situation and prospects for developing an ecosystem-based style of management in the Gulf of Cadiz. This particular socio-ecosystem is characterised by a clear focal ecosystem component—the role of the estuary of the Guadalquivir River as a nursery area—that has an influence on the marine ecosystem and at the same time concentrates a number of sectoral human activities. This nursery role particularly concerns the anchovy fishery, which is the most economically and culturally important fishery in the region. As a transition zone between river and marine environments, estuaries are particularly sensitive to human activities, either directly developed within the aquatic environment and its surroundings or further upstream within its catchment area. The particularities of the Guadalquivir socio-ecosystem, with an area of influence that extends as far as the city of Seville, require the consideration of multiple sectors and the corresponding conflicting interests. These include the shipping and tourism sectors, the agriculture, aquaculture, salt and mining industries, and the fisheries and conservation interests. This article aims to give an overview of the high-level policy goals and the jurisdictional framework, scope the sectors involved and describe the pressures and risks of their activities. It will identify conflicting interests relating to different visions of the ecosystem as well as the institutional arrangements that could be used to balance them and finally, put forward a vision for using ecosystem-based information to improve multi-sectoral management decisions.
      PubDate: 2016-10-12
       
  • Behaviours of Atlantic herring and mackerel in a purse-seine net, observed
           using multibeam sonar
    • Authors: Tenningen M; Macaulay GJ, Rieucau G, et al.
      Abstract: To ensure efficient and sustainable purse-seine fisheries, the catch process must be monitored to better understand the reactions of fish to the gear. In this study, we monitored the behaviours of herring (Clupea harengus) and mackerel (Scomber scombrus) schools during purse-seine capture using a multibeam imaging sonar (Simrad MS70, 75–112 kHz) mounted on a research vessel. The fish behaviours differed between species and purse-seine sets. For both species, the acoustic volume backscattering coefficient increased as 0–80% of the seine was hauled aboard, indicating a corresponding increase in fish spatial density. This increase was significantly greater for herring than mackerel. As 0–40% of the seine was hauled aboard the fishing vessel, schools changed their spatial distribution and volume independent of seine hauling, while for some schools, depth and height decreased. The acoustic volume backscattering strength was up to 25 dB higher in the centre of the school than in the edges. The average lateral target strength was estimated for individual fish in the captured herring schools, and the effect of incident angle on the backscattering strength is considered.
      PubDate: 2016-10-06
       
  • Feels like home: homing of mature large-bodied fish following
           translocation from a power-station canal
    • Authors: Taylor MD; Payne NL, Becker A, et al.
      Abstract: Fish translocation is a common method of conservation and fisheries enhancement. Monitoring post-translocation movements and migration provides useful information to inform translocation strategies. Three species of large-bodied fish (Yellowfin Bream Acanthopagrus australis, Luderick Girella tricuspidata, and Tarwhine Rhabdosargus sarba) impounded in a cooling water canal at a power station were translocated into the adjacent estuary (Lake Macquarie, New South Wales). Translocated fish were tagged with acoustic tags (n = 34) equipped with accelerometer sensors (providing a relative measure of fish activity) and released on either an artificial reef or a natural reef. In addition, 8 free-ranging Yellowfin Bream were captured and tagged on the artificial reef. Fish were tracked throughout Lake Macquarie on a dispersed array of 18 VemcoVR2W receivers, and on the artificial reef using a VR4-UWM Vemco Positioning System, for up to 11 months. Yellowfin Bream and Luderick rapidly migrated back to the power station, whereas Tarwhine remained near the release location. Translocated Yellowfin Bream showed divergent behavioural patterns to free-ranging Yellowfin Bream on the artificial reef, with much higher activity levels, elevated nocturnal activity, and different patterns of habitat usage, possibly reflecting divergent foraging behaviour. This study presents a rare example of non-natal homing to an artificial habitat in several large-bodied marine fish species. The role of low frequency sound in the homing of translocated fish, and factors contributing to the observed behavioural patterns are discussed. The presence of a homing signal which can facilitate return migration may decrease the efficacy of translocation efforts for adult marine fishes; however, these responses are species-specific and will require evaluation on a case-by-case basis.
      PubDate: 2016-10-05
       
  • Ageing bias and precision for deep-water snappers: evaluating nascent
           otolith preparation methods using novel multivariate comparisons among
           readers and growth parameter estimates
    • Authors: Wakefield CB; O’Malley JM, Williams AJ, et al.
      Abstract: Tropical deep-water snappers (Etelinae) support valuable fisheries across the Indo-Pacific, with stock assessments reliant on age-based information in the absence of reliable catch and effort statistics. These long-lived species have been considered notoriously difficult to age. However, nascent developments in ageing protocols, particularly thinner transverse sections of otoliths (∼180–200 µm), are providing improvements in growth zone clarity, interpretation and repeatability of annuli counts. At a recent international workshop, thin sectioned otoliths from three deep-water snappers were read under reflected light by eight fisheries scientists from across the Indo-Pacific, with various levels of fish-ageing experience. Precision and bias were assessed using traditional ageing precision metrics (index of average percent error, IAPE; and coefficient of variation, CV), and a novel approach using multivariate analyses (metric multidimensional scaling, mMDS) based on Euclidean dissimilarity among readers’ counts and subsequent von Bertalanffy (vB) growth parameter estimates. Annuli counts between the primary reader and all other readers were within two for 80% of estimates, with uniform variation across a wide age range for Etelis carbunculus (intraclass correlation coefficient (ICC) = 0.924, n = 20, 3–25 annuli) and Etelis sp. (ICC = 0.933, n = 15, 2–27 annuli). In contrast, annuli counts for Pristipomoides filamentosus (n = 14, 4–49) were less precise (i.e. ICC = 0.835, 66% of counts within two of primary reader) with a bias toward greater variation in younger, pre-maturational life stages (≤5 annuli). Traditionally accepted ageing precision (IAPE ≤ 5.5%, CV ≤ 7.6%) was achieved for each species, but was commensurate with reader experience. The multivariate mMDS ordination was more informative in identifying both distance (i.e. dissimilarity) and direction (i.e. form) of variations in annuli counts and vB growth parameter estimates among readers. The acceptable level of ageing precision and bias achieved among most readers indicated that deep-water snappers can be aged precisely when appropriate otolith preparation methods are used. This study contributes towards ageing protocols that can be used to (i) interrogate bias and precision of age data for stock assessments, and (ii) standardise comparisons of age-based life history characteristics across a species range.
      PubDate: 2016-09-29
       
  • Balanced harvesting is the bioeconomic equilibrium of a size-structured
           Beverton-Holt model
    • Authors: Plank MJ; .
      Abstract: Balanced harvesting (BH) was introduced as an alternative strategy to size-at-entry fishing with the aim of maintaining ecosystem structure and functioning. BH has been criticized on a number of grounds, including that it would require an infeasible level of micromanagement and enforcement. Recent results from a size-spectrum model show that the distribution of fishing mortality across body sizes that emerges from the behaviour of a large number of fishing agents corresponds to BH in a single species. Size-spectrum models differ from classical size-structured models used in fisheries as they are based on a bookkeeping of biomass transfer from prey to predator rather than a von Bertalanffy growth model. Here we investigate a classical Beverton-Holt model coupled with the Gordon-Schaefer harvesting model extended to allow for differential fishing pressure at different body sizes. This models an open-access fishery in which individual fishing agents act to maximize their own economic return. We show that the equilibrium of the harvesting model produces an aggregate fishing mortality that is closely matched to the production at different body sizes, in other words BH of a single species. These results have significant implications because they show that the robustness of BH does not depend on arguments about the relative production levels of small versus large fish.
      PubDate: 2016-09-28
       
  • Trade-offs in marine protection: multispecies interactions within a
           community-led temperate marine reserve
    • Authors: Howarth LM; Dubois P, Gratton P, et al.
      Abstract: This study investigated the effects of a community-led temperate marine reserve in Lamlash Bay, Firth of Clyde, Scotland, on commercially important populations of European lobster (Homarus gammarus), brown crab (Cancer pagurus), and velvet swimming crabs (Necora puber). Potting surveys conducted over 4 years revealed significantly higher catch per unit effort (cpue 109% greater), weight per unit effort (wpue 189% greater), and carapace length (10–15 mm greater) in lobsters within the reserve compared with control sites. However, likely due to low levels of recruitment and increased fishing effort outside the reserve, lobster catches decreased in all areas during the final 2 years. Nevertheless, catch rates remained higher within the reserve across all years, suggesting the reserve buffered these wider declines. Additionally, lobster cpue and wpue declined with increasing distance from the boundaries of the marine reserve, a trend which tag–recapture data suggested were due to spillover. Catches of berried lobster were also twice as high within the reserve than outside, and the mean potential reproductive output per female was 22.1% greater. It was originally thought that higher densities of lobster within the reserve might lead to greater levels of aggression and physical damage. However, damage levels were solely related to body size, as large lobsters >110 mm had sustained over 218% more damage than smaller individuals. Interestingly, catches of adult lobsters were inversely correlated with those of juvenile lobsters, brown crabs, and velvet crabs, which may be evidence of competitive displacement and/or predation. Our findings provide evidence that temperate marine reserves can deliver fisheries and conservation benefits, and highlight the importance of investigating multispecies interactions, as the recovery of some species can have knock-on effects on others.
      PubDate: 2016-09-28
       
  • Mark-recapture estimation of mortality and migration rates for sea trout (
           Salmo trutta ) in the northern Baltic sea
    • Authors: Whitlock RE; Kopra J, Pakarinen T, et al.
      Abstract: Knowledge of current fishing mortality rates is an important prerequisite for formulating management plans for the recovery of threatened stocks. We present a method for estimating migration and fishing mortality rates for anadromous fishes that combines tag return data from commercial and recreational fisheries with expert opinion in a Bayesian framework. By integrating diverse sources of information and allowing for missing data, this approach may be particularly applicable in data-limited situations.Wild populations of anadromous sea trout (Salmo trutta) in the northern Baltic Sea have undergone severe declines, with the loss of many populations. The contribution of fisheries to this decline has not been quantified, but is thought to be significant. We apply the Bayesian mark-recapture model to two reared sea trout stocks from the Finnish Isojoki and Lestijoki Rivers. Over the study period (1987–2012), the total harvest rate was estimated to average 0.82 y–1 for the Isojoki River stock and 0.74 y−1 for the Lestijoki River stock. Recreational gillnet fishing at sea was estimated to be the most important source of fishing mortality for both stocks, particularly during the 1980s and 1990s. Our results indicate a high probability of unsustainable levels of fishing mortality for both stocks, and illustrate the importance of considering the effect of recreational fisheries on fish population dynamics.
      PubDate: 2016-09-26
       
  • Incidental bycatch of northern fulmars in the small-vessel demersal
           longline fishery for Greenland halibut in coastal Norway 2012–2014
    • Authors: Fangel K; Bærum K, Christensen-Dalsgaard S, et al.
      Abstract: With seabird populations in rapid decline, understanding and reducing anthropogenic mortality factors is essential. One such factor is incidental bycatch in fisheries. Here we analyze bycatch in the small-vessel demersal longline fishery for Greenland halibut outside the coast of Northern Norway in 2012–2014, by means of self-reporting from fishers and independent observers. A sample of killed birds were analysed for sex, age, reproductive status and condition. Nearly all were northern fulmars. Estimated total bycatch for this fishery for the 3-year period was about 312 birds (SE ≈ 133) using a stratified estimator. Bycatch rate per 1000 hooks was estimated to approximately 0.031 (SE ≈ 0.012). Exploring per trip bycatch rates utilizing generalized linear mixed models, we found no convincing trends of environmental, spatial and temporal variables in explaining bycatch. However, trips using longlines with non-swivel hooks had a more than 100-fold larger bycatch rate (mean ≈ 0.760, SE ≈ 0.160) than those using swivel hooks (mean ≈ 0.008, SE ≈ 0.002). Further, trips with external observers had higher bycatch estimates (mean ≈ 0.75, SE ≈ 0.16) compared with trips where bycatch was registered by the fishers (mean ≈ 0.02, SE 
      PubDate: 2016-09-26
       
  • Balancing fishery and conservation: a case study of the barrel jellyfish
           Rhizostoma octopus in South Wales
    • Authors: Elliott A; Hobson V, Tang KW, et al.
      Abstract: In Wales, the barrel jellyfish Rhizostoma octopus is commercially harvested to produce high-value medical grade collagen. Although the fishery is presently not regulated, there are concerns how it may affect the leatherback turtle (Dermochelys coriacea), which preys on R. octopus in local waters. We combined monitoring data and morphometric and weight measurements in models to estimate the potential impact of R. octopus fishery on foraging turtles. We found a significant quadratic relationship between bell diameter and wet weight of R. octopus, with bell diameter explaining 88% of the variability in wet weight. R. octopus biomass in the Carmarthen Bay varied inter-annually between 38.9 and 594.2 tonnes y−1. The amount of R. octopus needed to satisfy a leatherback turtle’s daily energetic requirements was estimated at 85.1–319.1 kg. Using leatherback turtle sighting data, our models show that during a jellyfish ‘low year”, the R. octopus population could be completely depleted by an average of two foraging turtles along with the current level of commercial harvesting (4.3 tonnes). During a jellyfish “high year”, the current level of commercial harvesting is predicted to have relatively little impact on food supply for even the maximum number of foraging leatherback turtle reported in the area. However, uncertainties related to the jellyfish’s life cycle in the local waters need to be resolved for proper management of this emerging fishery.
      PubDate: 2016-09-20
       
  • New policies may call for new approaches: the case of the Swedish Norway
           lobster ( Nephrops norvegicus ) fisheries in the Kattegat and Skagerrak
    • Authors: Hornborg S; Jonsson P, Sköld M, et al.
      Abstract: The European Common Fisheries Policy has in its 2013 reform increased in complexity, such as a call for coherence with the Marine Strategy Framework Directive and a landing obligation, posing new requirements and challenges to managers, scientists and the fishing industry. Therefore, re-evaluations of current practice are important as a basis for management actions. The Swedish fishery for Norway lobster (Nephrops norvegicus) in the Kattegat–Skagerrak area provides an interesting case study of relevance to emerging policies. Sprung from an unbalance in available fish- and Nephrops quotas and an ambition to protect coastal areas, the current fishery has been directed towards three separate fisheries (mixed trawling, directed trawling using a sorting grid and creeling). Studying direct and indirect effects from alternative Swedish quota allocations among gear types is therefore interesting. Accordingly, a screening study was conducted, taking into consideration area-gear interactions in catch rates, to compare the three different fisheries regarding quantified pressures on the target species, the by-catch species, and on the seafloor, as well as to qualitatively discuss social and economic dimensions. In the next step, alternative quota allocations were studied. In Swedish fisheries, we show that creeling offers a substantial reduction of fishing mortality of both undersized Nephrops and fish and a reduced seafloor pressure per landed kilo of Nephrops. Given that the fishing areas in many cases may be interchangeable between gears, allocating a larger quota share to creels in the Swedish fishery would therefore contribute to the integration of fisheries- and environmental management as called for in the new policies.
      PubDate: 2016-09-16
       
  • Patterns of larval-stage connectivity of Atlantic cod ( Gadus morhua )
           within the Gulf of Maine in relation to current structure and a proposed
           fisheries closure
    • Authors: Churchill JH; Kritzer JP, Dean MJ, et al.
      Abstract: The decline of the Atlantic cod, Gadus morhua, stock in the Gulf of Maine to a historically low biomass has been coupled with a severe contraction in spatial range. The stock is now largely concentrated in the western Gulf of Maine. This erosion of spatial stock structure may be a factor-inhibiting recovery of Gulf of Maine cod. However, recent efforts to rebuild anadromous forage fish in the coastal Maine region coupled with the proposed creation of a new Eastern Maine Closed Area (EMCA), sited where localized depletion of the cod stock has been especially severe, might enable reestablishment of lost spatial structure of Gulf of Maine cod. We carried out larval transport modeling to examine the potential benefit of recovered cod spawning in the EMCA through supplying larvae to suitable juvenile settlement areas in the Gulf of Maine coastal zone and in the Cashes Ledge Closed Area (CLCA) in the central Gulf of Maine. The results indicate that an appreciable fraction of the larvae spawned in the EMCA are retained, to an age of settlement capability, in the coastal Maine region. Spawning in the EMCA may thus be a contributor of juveniles to a local, eastern Gulf of Maine, cod sub-stock. The results further indicate that spawning in the EMCA may supply a substantial subsidy of larvae to suitable juvenile habitat in the western Gulf of Maine and the CLCA. Protection of spawning stock in the EMCA may thus provide demographic benefits for the wider Gulf of Maine cod stock. Patterns of larval-stage connectivity between various potential spawning regions (including the EMCA) and areas of suitable juvenile habitat exhibit considerable interannual variability, which is predominantly linked to variability in the large-scale Gulf of Maine circulation. This result underscores the value of spatially explicit management as a means of fostering the recovery of the Gulf of Maine cod stock.
      PubDate: 2016-09-10
       
  • Consequences of catch-and-release angling for black bream Spondyliosoma
           cantharus , during the parental care period: implications for management
    • Authors: Pinder AC; Velterop R, Cooke SJ, et al.
      Abstract: Black sea bream Spondyliosoma cantharus is highly valued for its sporting and eating qualities. Due to its inshore spawning aggregations and male nest guarding behaviors, it is considered vulnerable to over-exploitation via recreational angling. Accordingly, greater uptake of the practice of catch-and-release (C&R) may provide some potential to limit the effects of angling on populations. Thus, the consequences of C&R for 40 S. cantharus (mean length 306 ± 10 mm) were assessed. Fish were sampled following their capture from charter boats by recreational anglers with varying levels of skill and experience. Of these fish, 17% were deeply hooked (e.g. in esophagus) and considered at high risk of post-release mortality (PRM). Blood lactate levels ranged between 0.40 and 2.60 mmol l − 1 (mean ± SE: 1.25 ± 0.09) and were significantly and positively correlated with fight time. Reflex impairments were observed in 32% of the catch, also suggesting an elevated probability of PRM. Hook damage was the only significant predictor of reflex impairment. The dominance of males (89%) across the catches highlighted the potential for additional indirect impacts of angling via the predation of eggs by conspecifics in the vacated nests of captured males. These results are discussed within the context of post-release performance of individual S. cantharus, the potential for C&R to limit impact at the population level and a need to consider future regulation of the fishery to ensure sustainability of stocks.
      PubDate: 2016-09-06
       
  • Genetic characterization of wild and farmed European seabass in the
           Adriatic sea: assessment of farmed escapees using a Bayesian approach
    • Authors: Šegvić-Bubić T; Grubišić L, Trumbić Ž, et al.
      Abstract: Hybridizations between domesticated escaped farmed fish and wild conspecifics may increase genetic diversity or break down locally adapted gene complexes, thus reducing competitive ability and overall fitness. We examined the genetic structure of six farmed populations of European seabass, Dicentrarchus labrax, of different geographical origin, and ten neighbouring wild populations in the Adriatic Sea using 10 microsatellite loci. All loci were polymorphic, with mean expected heterozygosity >74% in all 16 populations. Overall number of alleles as well as short-term effective population size were smaller in farmed (A = 18.7; Ne = 56.1) than in wild populations (A = 21.2; Ne = 180.6). The global FST of 0.0672 across loci showed significant population subdivision. Strong genetic differences between farmed fish and their wild conspecifics enabled the identification of seabass escapees back to their origins and the estimation of the extent of hybridization. Bayesian assignment analyses clustered wild populations together, whereas each farmed populations was assigned to a separate cluster. Intraspecific hybridization was highest in wild populations in areas impacted by fish farms, where highly admixed populations had decreased genetic diversity. The results of this study represent a solid foundation required to establish a genetic register of European seabass wild and farmed populations in the eastern Adriatic Sea that are required to establish a seabass DNA register.
      PubDate: 2016-09-06
       
  • Ecosystem indicators—accounting for variability in species’
           trophic levels
    • Authors: Reed J; Shannon L, Velez L, et al.
      Abstract: Trophic level (TL)-based indicators are commonly used to track the ecosystem effects of fishing as the selective removal of organisms from the food web may result in changes to the trophic structure of marine ecosystems. The use of a fixed TL per species in the calculation of TL-based indicators has been questioned, given that species’ TLs vary with ontogeny, as well as over time and space. We conducted a model-based assessment of the performance of fixed TL-based indicators vs. variable TL-based indicators for tracking the effects of fishing pressure. This assessment considered three TL-based indicators (the trophic level of the landed catch (TLc), the marine trophic index (MTI) and the trophic level of the surveyed community (TLsc)), three fishing scenarios that targeted specific model groups (the low TL scenario (LTL), the high TL scenario (HTL) and a scenario encompassing broad-scale exploitation (ALL)) and ten contrasting marine ecosystems with four types of ecosystem modelling approaches that differ in their structure and assumptions. Results showed that, overall, variable TL-based indicators have a greater capacity for detecting the effects of fishing pressure than fixed TL-based indicators. Across TL-based indicators, TLsc displayed the most consistent response to fishing whether fixed or variable species' TLs were used, as well as the highest capacity for detecting fishing effects. This result supports previous studies that promote the use of survey-based indicators over catch-based indicators to explore the impacts of fishing on the structure of marine ecosystems. Across fishing scenarios, the low trophic level fishing scenario (LTL) resulted in the lowest consistency between fixed and variable TL-based indicator responses and the lowest capacity of TL-based indicators for detecting fishing effects. Overall, our results speak to the need for caution when interpreting TL-based indicator trends, and knowledge of the broader context, such as fishing strategies and exploitation history.
      PubDate: 2016-08-27
       
  • Timing of growth zone formations in otoliths of the snapper, Chrysophrys
           auratus , in subtropical and temperate waters differ and growth follows a
           parabolic relationship with latitude
    • Authors: Wakefield CB; Potter IC, Hall NG, et al.
      Abstract: Chrysophrys auratus was collected from one sub-tropical and two temperate regions spanning >2400 km along the coast of Western Australia (∼23.5–35.5° S). Marginal increment analysis demonstrated that, while a single opaque zone is formed in the otoliths of C. auratus each year, the period of deposition varies among regions. An opaque zone was formed in May to early September in the sub-tropical upper west coast, and thus when water temperatures were declining to their minima. In contrast, opaque zone formation occurred 3 months later in August to December in the temperate lower west and south coasts, when water temperatures were rising from their minima. The length and age distributions differed markedly among populations of C. auratus, with the strongest year classes varying among the three regions. Thus, it is likely that year class strength of C. auratus throughout its distribution along the coast of Western Australian is mostly related to local environmental conditions. Chrysophrys auratus grew far less rapidly and attained a smaller size in the warmer upper west coast than in the cooler temperate regions of the lower west and south coasts. A collation of data on C. auratus from ten populations in Australia and three in New Zealand showed that growth is greatest towards the mid-latitudes of its geographic range, i.e. at ∼31° S. Estimates of mean lengths at specified ages thus exhibit a parabolic relationship with latitude, with reduced growth (i.e. edge-of-range effects) occurring towards the latitudinal margins of the distribution of this sparid.
      PubDate: 2016-08-27
       
  • Estimating uncertainty of data limited stock assessments
    • Authors: Kokkalis A; Eikeset A, Thygesen UH, et al.
      Abstract: Many methods exist to assess the fishing status of data-limited stocks; however, little is known about the accuracy or the uncertainty of such assessments. Here we evaluate a new size-based data-limited stock assessment method by applying it to well-assessed, data-rich fish stocks treated as data-limited. Particular emphasis is put on providing uncertainty estimates of the data-limited assessment. We assess four cod stocks in the North-East Atlantic and compare our estimates of stock status (F/Fmsy) with the official assessments. The estimated stock status of all four cod stocks followed the established stock assessments remarkably well and the official assessments fell well within the uncertainty bounds. The estimation of spawning stock biomass followed the same trends as the official assessment, but not the same levels. We conclude that the data-limited assessment method can be used for stock assessment and that the uncertainty estimates are reliable. Further work is needed to quantify the spawning biomass of the stock.
      PubDate: 2016-08-22
       
  • Overwinter shifts in the feeding ecology of juvenile Chinook salmon
    • Authors: Hertz E; Trudel M, Tucker S, et al.
      Abstract: Winter is thought to be a critical period for many fish in the ocean, but their ecology during this time tends to be poorly understood. We quantified the feeding ecology of juvenile Chinook salmon (Oncorhynchus tshawytscha) off the west coast of Vancouver Island in British Columbia, Canada, in autumn and winter to determine how seasonality could affect diet. Using stomach contents and stable isotopes, we tested the hypothesis that the winter diet of juvenile Chinook salmon differs from that of the autumn diet. Stomach-content data showed a shift from a primary reliance on amphipods in autumn to euphausiids in winter. This finding was generally corroborated by the stable isotope analysis, although mixing models suggested a greater contribution of fish prey to the diet in both autumn and winter. Understanding the diet of fish during winter may provide useful information for management as a first step in understanding the factors influencing mortality across life stages.
      PubDate: 2016-08-20
       
  • A reassessment of the fecundity type of Atlantic horse mackerel (
           Trachurus trachurus ) in Atlantic Iberian waters (ICES division IXa) shows
           that indeterminate spawners can cease recruiting oocytes during their
           spawning season
    • Authors: Ganias K; Mouchlianitis F, Nunes C, et al.
      Abstract: Following the classic lines of evidence of Hunter et al. (Hunter, J. R., Macewicz, B., Lo, N. C. H., and Kimbrell, A. 1992. Fecundity, spawning, and maturity of female Dover sole Microstomus pacificus, with an evaluation of assumptions and precision. Fishery Bulletin US, 90: 101–128.) on the fecundity type of fishes (determinate vs. indeterminate), the stock of horse mackerel (Trachurus trachurus) in Atlantic Iberian waters (ICES Division IXa) was shown to exhibit a mixed picture. Total fecundity, the total number of secondary growth (SG) oocytes dropped during the spawning season and there were reproductively active individuals with a distinct size hiatus between primary growth (PG) oocytes and SG oocytes, while no massive atresia was observed in late-season spawners. All of these characteristics matched with evidence for determinate fecundity. However, daily decrease rate of total fecundity was lower than daily specific fecundity (i.e. the number of eggs produced daily per unit weight) by orders of magnitude which suggested that the stock of SG oocytes was replenished during the spawning period through de novo oocyte recruitment. In addition, the maximum number of batches in reproductively active females was lower than the predicted annual number of spawnings, while total fecundity in recent spawners—those containing post-ovulatory follicles—was not lower than the fecundity of the remaining reproductively active females. All of these results suggest that, despite the aforementioned mixed lines of evidence, the fecundity of horse mackerel is clearly indeterminate. We attribute these mixed characteristics to the fact that, unlike most typical indeterminate spawners, horse mackerel ceases to recruit new SG oocytes during the latter part of its spawning season.
      PubDate: 2016-08-20
       
  • ecosystem-based management’?>Ecosystem considerations in Alaska: the
           value of qualitative assessments
    • Authors: Zador SG; Holsman KK, Aydin KY, et al.
      Abstract: The application of ecosystem considerations, and in particular ecosystem report cards, in federal groundfish fisheries management in Alaska can be described as an ecosystem approach to fisheries management (EAFM). Ecosystem information is provided to managers to establish an ecosystem context within which deliberations of fisheries quota occur. Our goal is to make the case for the need for qualitative ecosystem assessments in EAFM, specifically that qualitative synthesis has advantages worthy to keep a permanent place at the fisheries management table. These advantages include flexibility and speed in responding to and synthesizing new information from a variety of sources. First, we use the development of indicator-based ecosystem report cards as an example of adapting ecosystem information to management needs. Second, we review lessons learned and provide suggestions for best practices for applying EAFM to large and diverse fisheries in multiple marine ecosystems. Adapting ecosystem indicator information to better suit the needs of fisheries managers resulted in succinct report cards that summarize ecosystem trends, complementing more detailed ecosystem information to provide context for EAFM. There were several lessons learned in the process of developing the ecosystem report cards. The selection of indicators for each region was influenced by geography, the extent of scientific knowledge/data, and the particular expertise of the selection teams. Optimizing the opportunity to qualitatively incorporate ecosystem information into management decisions requires a good understanding of the management system in question. We found that frequent dialogue with managers and other stakeholders leads to adaptive products. We believe that there will always be a need for qualitative ecosystem assessment because it allows for rapid incorporation of new ideas and data and unexpected events. As we build modelling and predictive capacity, we will still need qualitative synthesis to capture events outside the bounds of current models and to detect impacts of the unexpected.
      PubDate: 2016-08-20
       
  • Tracking changes to a microplankton community in a North Atlantic sea loch
           using the microplankton index PI(mp)
    • Authors: Whyte C; Davidson K, Gilpin L, et al.
      Abstract: Microplankton plays a vital part in marine ecosystems, and its importance has been recognized by the inclusion of microplankton community composition in regulatory frameworks such as the European Water Framework Directive and the Marine Strategy Framework Directive as an indicator of ecological status. Quantitative techniques are therefore required to assess the environmental status of the microplankton in a water body. Here we demonstrate the use of a method known as the microplankton index PI(mp) to evaluate changes in the microplankton community of the west coast Scottish Sea Loch Creran. Microplankton in this fjord has been studied since the 1970s, providing a data set spanning four decades. Our analysis compares an arbitrarily chosen reference period between 1979 and 1981 with a period between 2011 and 2013 and demonstrates that between these two periods community structure has changed considerably with a substantial drop in the numbers of observed diatoms accompanied by a rise in the number of autotrophic/mixotrophic dinoflagellates as well as an increase in the potentially toxin producing genus Pseudo-nitzschia and that these are related to changes in both the intensity and timing of local patterns of precipitation. The PI(mp) is shown to be a useful and robust method to visualize and quantify changes in the underlying structure of the microplankton community and is a powerful addition to the toolbox of techniques needed to determine the health of our seas.
      PubDate: 2016-08-18
       
  • Nash equilibrium can resolve conflicting maximum sustainable yields in
           multi-species fisheries management
    • Authors: Norrström N; Casini M, Holmgren NA, et al.
      Abstract: The current fisheries management goals set by the European Commission states that fish stocks should be harvested to deliver maximum sustainable yields (MSY) and simultaneously, management should take ecosystem considerations into account. This creates unsolved trade-offs for the management of the stocks. We suggest a definition of a multi-species-MSY (MS-MSY) where no alternative fishing mortality (F) can increase yield (long term) for any ecologically interacting stock, given that the other stocks are fished at constant efforts (Fs). Such a MS-MSY can be solved through the game theoretic concept of a Nash equilibrium and here we explore two solutions to this conflict in the Baltic Sea. We maximize the sustainable yield of each stock under two constraints: first, we harvest the other stocks at a fixed F (FNE); second, we keep the spawning stock biomasses of the other stocks fixed [biomass Nash equilibrium (BNE)]. As a case study, we have developed a multi-species interaction stochastic operative model (MSI-SOM), which contains a SOM for each of the three dominant species of the Baltic Sea, the predator cod (Gadus morhua), and its prey herring (Clupea harengus), and sprat (Sprattus sprattus). For our Baltic Sea case, MS-MSYs exist under both the FNE and the BNE, but there is no guarantee that point solutions exists. We found that the prey species’ spawning stock biomasses are additive in the cod growth function, which allowed for a point solution in BNE. In the FNE, the herring MSY was found to be relatively insensitive to the other species’ fishing mortalities (F), which facilitated a point solution. The MSY targets of the BNE and the FNE differ slightly where the BNE gives higher predator yields and lower prey yields.
      PubDate: 2016-08-18
       
  • Performance of bycatch reduction devices varies for chondrichthyan,
           reptile, and cetacean mitigation in demersal fish trawls: assimilating
           subsurface interactions and unaccounted mortality
    • Authors: Wakefield CB; Santana-Garcon J, Dorman SR, et al.
      Abstract: To improve bycatch mitigation of chondrichthyans, reptiles and cetaceans for a tropical demersal fish-trawl fishery, species-specific responses to bycatch reduction devices (BRDs) were investigated using both in situ subsurface and onboard observations. There are few, if any, studies that have determined mitigation performances of BRDs from subsurface interactions for these species, as most are rarely encountered and thus require substantial levels of observer coverage for robust assessments. This study combined in-net and onboard (774 day trawls and 1320 day trawl hours of subsurface observer coverage) electronic monitoring on all fish-trawl vessels (n = 3) to compare bycatch mitigation performances among nine megafauna groups, based on escape rates and interaction durations for three BRDs over 6 months (June to December 2012). Overall, 26.9% of day trawls had no megafauna interactions and 38.3% of the 1826 interactions escaped, with most in rapid time (91.4% in ≤ 5 min). The upward inclined exclusion grid significantly improved the escape proportions for most chondrichthyans by 20–30%. All BRDs were highly effective in reducing reptile (turtles and seasnakes) bycatch, but irrelevant for the few sawfish (n = 13) that readily entangled in the anterior of the net. Cetacean (bottlenose dolphins only) interactions with BRDs were very rare (n = 7) despite high levels of attendance and depredation during trawling. Loss of targeted teleosts through the BRD hatch was rare (1.3% of day trawls). This relatively cost-effective method of electronic monitoring achieved very high levels of subsurface observer coverage (60% of day trawls or 56% of day trawl hours), and provided evidence that the subsurface expulsion of megafauna in poor condition is negligible. Furthermore, this study provides species-specific improvements toward bycatch mitigation strategies for demersal fish trawling.
      PubDate: 2016-08-17
       
  • Effectiveness of lobster fisheries management in New Zealand and Nova
           Scotia from multi-species and ecosystem perspectives
    • Authors: Eddy TD; Araújo JN, Bundy A, et al.
      Abstract: In New Zealand and Nova Scotia, lobster (Jasus edwardsii and Homarus americanus, respectively) is the most valuable export fishery. Although stock assessments and indicators assist in evaluating lobster fisheries, ecosystem effects are largely unknown, hindering ecosystem-based fisheries management (EBFM). We employed ecosystem models for the Cook Strait, New Zealand and western Scotian Shelf, Nova Scotia, Canada, to evaluate trade-offs between catches and ecosystem impacts in lobster fisheries from single- and multi-species perspectives. We ran simulations to independently determine exploitation rates that produced maximum sustainable yield (MSY) for lobster, and for all fished groups. We then ran simulations using these MSY exploitation rates simultaneously, and simulations to maximize multi-species MSY (MMSY). Our results indicate that current lobster exploitation rates in both regions are greater than those producing MSY, and have significant ecosystem impacts. Simulating multi-species fisheries, in both systems the sum of single-species MSY for all fished groups was less than the sum of catches where exploitation rates were run simultaneously. Runs maximizing MMSY across the entire ecosystem increased exploitation rates on many fished groups, and produced even greater total catch—yet with much greater ecological costs—and in Nova Scotia, collapses of sharks, large predators, and lobster themselves. As fisheries management moves towards multi-species and ecosystem-based approaches, we suggest that MMSY targets should be treated similarly to MSY—not as a target, but a limit. Even then, careful evaluation is required before implementation to ensure that there are no undesirable economic or ecological consequences.
      PubDate: 2016-08-10
       
  • Spatial prediction of demersal fish diversity in the Baltic Sea:
           comparison of machine learning and regression-based techniques
    • Authors: Smoliński S; Radtke K, .
      Abstract: Marine spatial planning (MSP) is considered a valuable tool in the ecosystem-based management of marine areas. Predictive modelling may be applied in the MSP framework to obtain spatially explicit information about biodiversity patterns. The growing number of statistical approaches used for this purpose implies the urgent need for comparisons between different predictive techniques. In this study, we evaluated the performance of selected machine learning and regression-based methods that were applied for modelling fish community indices. We hypothesized that habitat features can influence fish assemblage and investigated the effect of environmental gradients on demersal fish diversity (species richness and Shannon–Weaver Index). We used fish data from the Baltic International Trawl Surveys (2001–2014) and maps of six potential predictors: bottom salinity, depth, seabed slope, growth season bottom temperature, seabed sediments and annual mean bottom current velocity. We compared the performance of six alternative modelling approaches: generalized linear models, generalized additive models, multivariate adaptive regression splines, support vector machines, boosted regression trees and random forests. We applied repeated 10-fold cross-validation, using accuracy as the measure of model quality. Finally, we selected random forest as the best performing algorithm and implemented it for the spatial prediction of fish diversity from the Baltic Proper to the Kattegat. To obtain information on the data reliability and confidence of the developed models, which are essential for MSP, we estimated the uncertainty of predictions with standard deviation of predictions obtained from all the trees in the ensemble random forest method. We showed how state-of-the-art predictive techniques, based on easily available data and simple Geographic Information System tools, can be used to obtain reliable spatial information about fish diversity. Our comparative work highlighted the potential of machine learning method to reduce prediction error in modelling of demersal fish diversity in the framework of MSP.
      PubDate: 2016-08-05
       
  • Changes in size, age, and sex ratio composition of Pacific bluefin tuna (
           Thunnus orientalis ) on the northwestern Pacific Ocean spawning grounds
    • Authors: Shiao J; Lu H, Hsu J, et al.
      Abstract: The Pacific bluefin tuna (Thunnus orientalis, PBF), an iconic fisheries species, is heavily exploited and its biomass is at a historically low level. To enhance effectiveness of management and conservation, a study was initiated to examine the demographic changes of the PBF between 2002 and 2015. Annual tuna age compositions were estimated by applying an empirical age-length key, based on the ages and lengths of 892 fish, to the length frequencies observed among annual catches in the northwestern Pacific spawning grounds located near Taiwan. Ages of the spawners concentrated in 7–20-years old (range = 4–28 years), corresponding to fork lengths between 200 and 240 cm. The size and age compositions were influenced by the strong 1994 and 1996 year-cohorts, which showed a relatively high abundance in most years except 2007–2009. Between 2013 and 2015, recruits of 2005–2009 year-cohorts (age 6–10) increased in relative abundance while the strong 1994 and 1996 year-cohorts decreased as they neared the end of their lifespan. PBF smaller than 200 cm were rarely found in the tropical areas and the mean sizes of the PBF caught south of 24°N were significantly larger than those caught north of 24°N. These results suggested that the choice of spawning latitudes of the PBF was influenced by the size of spawning adults. The sex ratio of smaller (240 cm) were male biased (62–100%). The size and age composition of the PBF was mainly influenced by the recruitment of young spawners and was less sensitive to the catch of longline fisheries. However the impact of longline fisheries on the reproductive potential of this species warrants further investigation.
      PubDate: 2016-08-05
       
  • Monitoring of reef associated and pelagic fish communities on
           Australia’s first purpose built offshore artificial reef
    • Authors: Becker A; Taylor MD, Lowry MB, et al.
      Abstract: Artificial reefs now form part of an integrated approach to enhance fisheries around the world. A responsible approach to artificial reef deployment calls for clear, well defined goals prior to any reef being placed in the field, followed by subsequent monitoring to assess whether these goals are being achieved. In this study, to evaluate if an artificial reef off Sydney was meeting its goal of providing quality fishing opportunities through the establishment of a complex fish assemblage, a 4-year monitoring program was designed. This program examined the response of reef-associated and pelagic fishes to the deployment of a purpose built offshore reef, relative to control reefs. Fish were observed immediately following deployment, but the artificial reef fish assemblage remained distinct from the three natural control reefs throughout the monitoring period. Also, the artificial reef displayed inter-annual variability associated with successional processes, which was not evident on the natural reefs. Fish length data indicated that the artificial reef was providing resources for both juvenile and adults of a number of species. This study demonstrates artificial reefs can provide habitats for a diverse group of fish, but the assemblages are unlikely to mimic those on natural reefs. We have also shown that longer term monitoring periods, covering multiple years are required to gain a robust understanding of the response of fish to reef deployment. This information can be used to understand the benefits and limitations of future artificial reef deployments.
      PubDate: 2016-08-04
       
  • Highly mixed fisheries: fine-scale spatial patterns in retained catches of
           French fisheries in the Celtic Sea
    • Authors: Mateo M; Pawlowski L, Robert M, et al.
      Abstract: Efficiency of mixed-fisheries management and operational implementation of the ecosystem approach to fisheries management rely on the ability to understand and describe the technical and biological interactions between fleets, gears and species. The present study aims to describe fine-scale spatial patterns of the French demersal mixed fisheries in the Celtic Sea and discusses their implications in terms of management. Analysis was made by integrating vessel monitoring systems and logbook data collected between 2010 and 2012 at a 3′*3′ spatial scale through the use of principal component analysis followed by hierarchical clustering. It revealed spatial regions defined by a distinct homogeneous composition of retained catches. Each cluster was also described in terms of the fishing activity: vessel length, effort, power and gear used. The analysis revealed a complex spatial structure in the species assemblage caught and suggests that a single situation cannot describe the mixed fisheries of the Celtic Sea, but rather that there are several distinct cases of mixed fisheries. Our results also highlight the limitations of using the current level of data aggregation commonly requested in international data calls to model these fisheries and suggest that improvements should be made to ensure efficient evaluation of management options. Analyses of spatially resolved fisheries data such as the one presented here open a range of potential applications. In the context of the Common Fisheries Policy reform and the landing obligation, comparison of our results with applications of the same methodology to a subset of vulnerable species or to catches of fish below the minimum conservation reference size would help to identify the geographical areas to avoid and assess potential effort reallocation strategies based on groups of target species.
      PubDate: 2016-08-04
       
  • Can less be more? Effects of reduced frequency of surveys and stock
           assessments
    • Authors: Zimmermann F; Enberg K, .
      Abstract: Uncertain and inaccurate estimates are a prevailing problem in stock assessment, despite increasingly sophisticated estimation methods and substantial usage of scientific and financial resources. Annual scientific surveys and assessment group meetings require frequent use of research vessels and skilled research staff and are, therefore, particularly costly. This data- and work-intensive approach is often considered paramount for reliable stock estimates and risk management. However, it remains an open question whether the benefits of increasing assessment effort outweigh its marginal costs, or whether the potential impacts of investing less in assessments could generate net benefits. In this study, we explore how different scenarios of reduced survey and assessment frequencies affect estimated stock biomass, predicted catch, and uncertainty. Data of two Northeast Atlantic stocks, blue whiting (Micromesistius poutassou) and Norwegian spring-spawning herring (Clupea harengus), and a widely applied stock assessment model are used to compare the impacts of removing surveys and/or annual assessments. The results show that lower survey and/or assessment frequencies tend to result in deviating estimates of spawning-stock biomass and catch and larger confidence intervals, the observed differences being, however, mostly small. While scenarios without a survey datapoint in the assessment year generally produced the largest deviations in estimates, biannual surveys in general did not affect assessment performance substantially. This indicates that a reduced frequency of surveys and assessments could be an acceptable measure to reduce assessment costs and increase the efficiency of fisheries management, particularly when accompanied by thorough management strategy evaluations and risk assessments.
      PubDate: 2016-08-03
       
  • Age-specific differences in the seasonal spatial distribution of
           butterfish ( Peprilus triacanthus )
    • Authors: Adams CF; .
      Abstract: The spatial distribution of butterfish (Peprilus triacanthus) in the Northwest Atlantic Ocean was investigated using a suite of spatial indicators based on Northeast Fisheries Science Center spring and fall bottom trawl survey data, 1982–2013. In the spring, ages 2 and 3 were found farther northeast and deeper than age 1 butterfish, while in the fall, age 3 butterfish were found farther northeast and deeper than ages 0 and 1. There was no significant northward movement of butterfish in spring or fall over the course of either time-series. However, there was a significant increase in the area occupied by ages 1–3 in the spring that was correlated with surface temperature. This illustrates that responses to climate change may be manifested as range expansions, rather than poleward movement of the centre of gravity (i.e. bivariate weighted mean location of the population). Two changes were observed over the course of the fall time series, both for ages 1 and 2: increased spatial dispersion; and a decrease in depth. The former result would have been masked, while the latter would have been erroneously generalized to all age classes, if an age-specific analysis had not been done. This study demonstrates the importance of an age-based and seasonal analysis. It is also shown how a spatial distribution analyses can inform stock assessments by providing insights into diverging survey indices and availability to surveys in general. Similarly, spatial distribution analyses can be used to verify the spatial equilibrium assumption for the calculation of biological reference points.
      PubDate: 2016-07-29
       
 
 
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