This contribution discusses the modular approach to the assessment and management of large marine ecosystems (LMEs). It addresses the contents and functions of the five modules; the key elements and processes of the Transboundary Diagnostic Analysis (TDA), Strategic Action Program (SAP) and National Action Plan (NAP) in the LME context; the principal common problems facing LMEs and their causes identified in TDAs and action plans formulated in SAPs, as the results of the practical application of the modular approach in LME projects. It also evaluates the significance of the modular approach for international ocean governance. It concludes that this integrated, ecosystem-based approach has rectified some deficiencies of the traditional sectoral approaches and has improved the understanding of LMEs and their management regimes. As a result the integrated, ecosystem-based approach is increasingly being endorsed in international governance of LMEs.
This article addresses interdisciplinary sustainable aspects of fisheries as linkages for the adaptive management of large marine ecosystems (LMEs). Natural and human-induced impacts on living marine resources are considered. Management and the ecological aspects of fish stock populations in the United States Northeast Continental Shelf ecosystem are examined for prospective and emerging “best practices” from a synthesis of the scientific literature. With the passage of the Oceans Act of 2000 (Public Law 106–256; e.g. Watkins 2002) in the United States, this article seeks to enhance the fostering of sustainability through natural and social science by forging linkages between the best available science practice and the “precautionary approach” that includes ecosystem considerations of fish stocks as component parts of a representative model LME.
In this chapter we develop a method to estimate the value of an ecosystem reserve for Atlantic herring in the U.S. Northeast Shelf Large Marine Ecosystem. Herring and other small pelagic species are important forage for other fish and marine mammals in the ecosystem. A reduction in the commercial total allowable catch (TAC) would create an ‘Ecosystem Reserve’ (ER) for herring, which may increase the residual stock of herring that would be available to other species in the ecosystem. An increase in ER (i.e. a reduction in TAC) may imply reduced benefits of commercial harvest, and, as an offset, we may realize added benefits for the ecosystem from the ER. Conversely, an increase in TAC may result in increased commercial benefits at the expense of reduced ecosystem benefits. The approximate magnitudes of these two changes—added and reduced benefits—are the focus of this chapter.
The single-species approach to fisheries management is under fire as valuable fish stocks around the world continue to collapse despite 25 years of extended federal jurisdiction and intensive government regulations. Consensus is mounting for ecosystem-based approaches, but few tangible alternatives have been offered. We propose a two-part portfolio approach to multi-species management which integrates the fish and fisheries, socioeconomic, and governance modules of the LME model. The portfolio framework is a technical methodology which explicitly integrates fish stocks that are jointed by ecology (e.g., predation) and fishing technology (e.g., mixed-species fisheries), and selects combinations of species biomass and other stock attributes (e.g. fish size, recruitment patterns, growth rates) that balance expected aggregate returns for society against the risks associated with ecological, market, and institutional uncertainties. The technical framework is complemented by property rights institutions that remove the wedge between harvest and stock rights now in place in government regulatory regimes. New property rights institutions are needed which create incentives for harvesters to regard fish stocks as capital assets that potentially produce benefits for society indefinitely, internalize spillovers among fisheries caused by ecological and technological interactions, and reduce uncertainty through investments in information.
The industries linked to the uses of a large marine ecosystem (LME) have a substantial influence on contiguous coastal economies. We estimate the economic activity of U.S. marine sectors associated with the Northeast Shelf LME. Our best upper bound estimate of total output impact is $339 billion, including a total “value-added” impact of $209 billion. Total employment impacts are estimated on the order of 3.6 million persons. The estimate of total value-added impact is approximately 10% of the $2.2 trillion total gross state product for the region. In the future, critical interactions between industrial sectors and the ecological health of the Northeast Shelf will affect economic activity in opposing ways.
LMEs encompass many living and non-renewable resources, each having multiple physical or relational attributes. For example, fish stocks can be differentiated by species, age structure, growth rates, distribution, gene pool, diet, and habitat. Each resource attribute is potentially valuable, but attributes are also costly to manage. Property rights arrangements that bundle fishery resource attributes are recommended. Bundled property rights could evolve from a comprehensive assignment of usufruct rights in fisheries, such as IFQs (individual fishing quotas) or harvest cooperatives, which reduce the transaction costs of gathering information on unspecified stock attributes and of internalizing interactions due to ecology (e.g., predation), unspecialized fishing technologies (e.g., bycatch in mixed-species fisheries) and impacts of fishing gear on habitat and non-commercial species.
Sustainability has become the focus and organizing principle for the reconciliation of economics and the environment. The concept has led to the emergence of holistic or ecosystem-based management approaches where maintenance of the environment and associated ecosystems in acceptable condition indefinitely is the goal. Application in management contexts, however, remains an immense challenge. Globally, environments continue to degrade, especially in third world countries. While the scientific basis for such management approaches remains an issue, many of the impediments to acceptable performance in governance lie in the human dimensions. Performance is a function of institutional capacity, the complex of people, infrastructure, education, resources and legal framework that determines societal response to environmental decisions. The Sea Grant Paradigm, whereby universities partner with federal governments to create centers that conduct programs of research, education and outreach on management critical problems, holds great promise as an institution for building long-term global capacity to manage marine environments. The paradigm is particularly powerful in developing the human dimensions so critical to good marine governance. Sea Grant is culturally and administratively adaptable to both developed and developing countries. Nine specific human dimension elements inherent in the Sea Grant model are described in the context of holistic management of large marine ecosystems.
The Benguela project is unique among LMEs in seeking to go beyond diagnosis to useful forecasting. That is a daunting challenge. This essay shows how 21st century modelling practice might be applied to forecasting LMEs. It addresses signal-to-noise and predictability in modelling the marine ecosystem. That leads to four classes of forecast systems to provide information about changes on short, medium and long term, and for planning. Each is limited by predictability: the first in the atmospheric weather (Nowcasting), the second in the oceanic weather (Forecasting) and the third in the ecosystem itself (Climate prediction). The fourth class, What-if' Prediction, avoids these limits by combining hindcast boundary conditons, with scenarios for exogenous events. The essay closes with a vision of the future that extends L.F. Richardson's pioneering work in meteorology, to operational prediction of LMEs.
Getting useful and effective marine forecasts to the community is a key objective of the Benguela Current Large Marine Ecosystem Programme. This chapter examines recommendations from the Workshop sessions which might be incorporated into the design of a future integrated forecast system for the BCLME. Five candidate predictive capabilities are identified for priority action, and assessed for their relevance and value to the region. The system requirements needed to realise these predictive capabilities are reviewed, and additional infrastructural capacity noted. Finally, the elements of a future integrated Benguela Regional Forecast Facility are set down as a challenge for joint action by the countries of the region.
This chapter focuses on describing, discussing and evaluating the feasibility of forecasting selected shelf processes considered to be of relevance in terms of their impacts on commercially important living marine resources of the BCLME. The impact of shelf processes is examined with regard to both the availability of resources to fishing and their abundance. Three shelf processes, namely low oxygen water events, mesoscale processes, and boundary processes, are examined separately and in detail. For each of these processes, the resource impacted and its response, the type of forecast considered appropriate and feasible, the requirements for making such forecasts, and case studies illustrating examples of forecasting systems already in place, are provided. Other processes that may have significant impacts on living marine resources are briefly discussed. The technology for forecasting low oxygen water events is available and therefore the feasibility of making such predictions is good, although at present there are insufficient moored instruments dedicated to inshore oxygen monitoring in relevant areas, either in the northern or southern Benguela regions. Indices of mesoscale processes have been used in attempts to forecast anchovy recruitment variability in the southern Benguela, and indices of boundary processes to hindcast hake recruitment variability in the northern Benguela. For southern Benguela anchovy, the wealth of studies relating environmental variability to recruitment variability and the insights gained from simulating the incorporation of predictive models into management procedures for this stock, should allow the development of recruitment prediction models that can feasibly be incorporated into management procedures. However, the incorporation of environmentally-based recruitment or stock size prediction models into management procedures should take account of assumptions and uncertainties associated with such models, and their potential for utility to management should be tested through simulation.
Three scales of LOW variability were found to be amenable to forecasting as well as being suitable to provide information that would be of use to management response plans. u ⊙ Short time scale: 7 day lead events linked to local wind variability and “HABs” ⊙ Medium Time Scale: 2 month lead events linked to “ETSA” easterly equatorial winds ⊙ Decadal Time Scale: in ‘what if’ scenarios where the uncertainties are large in respect to forecasting forcing variability. The areas where LOW forecasting can be of benefit include: u ⊙ Input to stock assessment and ecosystem management models to provide a more sensitive indicator of the mortality/behavioural modification risk particularly when the variability is modulated by regime shifts. ⊙ Direct management response to a threat to stocks: rock lobster where it is practically possible to operate a contingency plan. ⊙ Ecosystem scale assessment of the risk posed by LOW to habitat suitability and trends in TAC size. This applies to a capability of assessing indirect impacts on stocks through impacts on the food web or on underlying, services. ⊙ Climate change: the uncertainties linked to climate change are of importance because the time scales match those of the depreciation of capital investments in fisheries. Assessment of the risk of natural ecosystem degradation through increased impact of LOW from the equatorial system. Forecasting will only be a reality when the key gaps in process level understanding are addressed. This is underway and it is likely that hind casting will be possible by 2007 with true operational forecasting linked to ecosystem effects available by 2012.
Long-term ecosystem changes in the Benguela region include species alternations and regime shifts, which are sometimes obscured by large intra- and inter- annual variability in the ecosystem. This chapter proposes that no single model or approach can resolve this variability and effectively detect and predict long-term ecosystem changes; a coherent, robust, transparent and reproducible synthesis framework is required. Indicators and models are described that can be used to identify some aspects of the current state of ecosystem structure and to detect and monitor long-term change. A short-term challenge is to synthesize these varied sources of multidisciplinary (and sometimes contradictory) information in a logical and consistent fashion. An expert system approach is proposed to do this, consolidating results of different indicators and models within a dynamic process that uses feedbacks to validate predictions of the expert system, and to improve it. It is suggested that such an approach should be initiated in the short term, even as models and indicators are being developed further. In parallel, multivariate statistical tools should be refined and applied to existing time series, to identify past periods of ecosystem change. Current data gaps should be filled, including time series of primary production and the abundance of gelatinous zooplankton. In the medium term, the expert system model should evolve to a point where its results can be used to inform various management groups about the state of the ecosystem. Part of this evolution requires that ecosystem indicators be presented with error estimates or formal assessments of quality.
This chapter has reviewed the major large scale modes that exist in the South Atlantic as well as those external to the region such as ENSO and the Antarctic Oscillation that may influence the BCLME region. Most attention has been paid to the Benguela Niño which is the most well known and dominant mode in the South East Atlantic. In addition to these large scale modes, the highly variable southern Agulhas Current also influences at least the southern part of the BCLME region. Some of the Agulhas Current variability develops locally due to instability processes but at least part may be linked to that evolving in the tropical Indian Ocean. Although the most recognizable feature of the BCLME region is its upwelling, the strength and timing of this process and its related SST expression is modulated by ENSO and likely also by other large-scale modes of variability. In the north of the BCLME region, the Benguela Niño impacts on the Angola—Benguela frontal zone and on SST to as far south as about 25°S. The proximity of the BCLME region to the Southern Ocean and the South West Indian Ocean, due to the termination of Africa in the sub-tropics, means that the Benguela upwelling system tends to display greater variability than do the Humboldt, Canary or California Current upwelling systems. Better understanding of this variability is fundamental for assessing its potential predictability and for developing appropriate management strategies of its rich ecosystems. A concern is the relative sparseness of in situ observations in the region. These include not only ocean data but also land surface and atmospheric data which, amoungst other applications, are needed to improve the reliability of the NCEP re-analyses often used to diagnose modes of variability over the region. In particular, prediction efforts for the region are significantly hindered by a lack of data with which to validate model outputs. Close collaboration between the observing system and modelling communities is therefore needed in order to make progress on better understanding the variability of the BCLME region and working towards prediction.
The three eastern boundary ecosystems comparable to the Benguela ecosystem (BCE) display differences and commonalities. The California (CalCE) and Humboldt Current (HCE) ecosystems are continuous topographically, whereas the Canary Current ecosystem (CanCE) is interrupted by the Gulf of Cadiz and the Canaries archipelago. All have similar regimes of equatorward flow over shelf and slope associated with upwelling and a subsurface poleward flow over the slope, though in the HCE multiple flows and counter-flows appear offshore. All systems exhibit year round upwelling in their centre and seasonal upwelling at their extremes as the trade wind systems that drive them migrate north and south, though the HCE is strongly skewed toward the equator. All systems vary on scales from the event or synoptic scale of a few days, through seasonal, to inter-decadal and long term. Productivity of each system follows the upwelling cycle, though intra-regional variations in nutrient content and forcing cause significant variability within regions. The CanCE is relatively unproductive compared to the CalCE and HCE as a result of differences in large scale circulation between the Pacific and Atlantic. The latter two systems are dominated by El Niño-Southern Oscillation (ENSO) variability on a scale of 4–7 years. Physical modeling with the Princeton Ocean Model and the Regional Oceanic Modeling System has advanced recently to the stage of reproducing realistic mesoscale features and energy levels with climatic wind forcing. Operational forecasting by these models with assimilation of sea surface temperature and other data is successfully implemented in CalCE. On longer time scales, the Lamont-Doherty Earth Observatory model is able to hindcast El Niño variability over the long term up to 2 years in advance. Empirical ecological models in all three systems have attempted prediction of permissible catch level (fractional Maximum Sustainable Yield), recruitment, catches or onset of migration with lack of continued success, partly because discontinuous or inadequate observations hamper model implementation and assessment. Moreover, empirical models tuned to particular environments fail when fundamental regime shifts occur. One of the most successful approaches is that of intensive monitoring of catch and environmental parameters linked to an informal Operational Management Procedure (OMP) to inform fisheries management off Peru. This OMP contributed to preservation of anchovy stock during the 1997-8 El Niño but remains to be formalized or tested under varying conditions. Prediction on time scales of global warming are uncertain because physical climate models still disagree on whether upwelling will intensify or weaken. Possible scenarios on decadal scale based on warming or cooling of waters in the Eastern Boundary Current systems can be proffered, albeit with little confidence at present. Future approaches for all systems, including the BCE, will in the long run likely combine coupled atmospheric/ocean models with biological process models. Judicious application of purely statistical modeling based on inherent time series properties will assist, though such techniques are unable to cope with regime shifts.
Interannual and decadal-scale variability in abundance, distribution and biological characteristics are described for important living marine resources of the Benguela Current system including small pelagic fish, horse mackerel, hakes, snoek, rock lobster, Cape fur seals, Cape gannets and African penguins. Variability at the ecosystem level for the northern and southern subsystems is also described using trophodynamic indices that track structural changes in the ecosystem. Current understanding and analysis of observed variability in both resources and the ecosystem is reviewed, and the knowledge required for predicting resource and ecosystem variability and the causal factors that need to be considered are discussed. We highlight the need to improve understanding of the processes that are important in Benguela Current ecosystem, to identify what controls those processes, and to quantify such controls (particularly those acting on lower trophic levels) and the role of important species in the ecosystem. The kinds of predictions considered possible in the Benguela Current system are examined, and a series of steps is suggested to improve understanding of ecosystem and fisheries dynamics and to monitor key aspects of the ecosystem.
Harmful Algal Blooms (HABs) in the southern Benguela are usually attributed to dinoflagellate species, which constitute a regular component of normal phytoplankton populations. Fundamental to the success of HAB predictive systems is a sound knowledge of their variability. Although the Benguela remains poorly explored in terms of phytoplankton distribution, important biogeographic differences between the northern and southern Benguela, and the West Coast and Western Agulhas Bank have been reported and are reflected in the composition of HABs. The southern Benguela is characterized by clear seasonal trends, and high phytoplankton biomass and productivity during the latter months of the upwelling season can be attributed largely to dinoflagellate populations. Superimposed on the seasonal trend of increasing dinoflagellates and phytoplankton biomass are shorter successional patterns associated with spatial and temporal transitions in water column stratification driven by wind cycles and coastal topography. Understanding the mechanisms that control the transport, concentration and dissipation of dinoflagellate blooms is critical in predicting their coastal impact. For this purpose models of coastal wind-driven upwelling are required to reproduce both across-shelf and alongshore dynamics. Such information stands us in good stead in attempts to predict high biomass dinoflagellate blooms which impact the Benguela through low oxyten and hydrogen sulphide events. Less progress has been made on species-specific prediction fundamental to the prediction of toxin related events.
This article reviews the variability of plankton over time scales ranging from mesoscale upwelling events of a few days' duration to decadal scale changes in the northern and southern subsystems in the Benguela Current. It focuses on the plankton that are considered important for fish, particularly the crustacean zooplankton. The southern Benguela is strongly pulsed over periods of 4–12 days with a series of upwelling events modulated by passing cyclonic weather systems. The northern Benguela is less pulsed with short-term variability linked to continental shelf waves. Upwelling is particularly active at seven major sites in the Benguela system. Dense phytoplankton blooms develop in the cool nutrient-rich plumes, which merge and blend with surrounding waters, creating a broad band of phytoplankton-rich water over the shelf. Species succession from small to large diatoms, dinoflagellates and small flagellates occurs as the waters mature after upwelling and generally move offshore, although numerous exceptions occur, with small-celled communities occasionally dominant in nearshore waters. Much regeneration and recycling of nutrients occurs, resulting in lower than expected f-ratios. Frontal zone aggregations provide important feeding opportunities in the transport phase of ichthyoplankton between the Agulhas Bank spawning grounds and the nursery grounds on the South African West Coast. The Angola-Benguela front in the northern Benguela is also an important region for pelagic fish spawning. Seasonal changes in wind forcing indicate maximum upwelling in spring and autumn throughout the Benguela, with a tendency for a summer maximum in the south. Lüderitz (25oS) and Cape Frio (17oS) are particularly active upwelling regions. Phytoplankton biomass, estimated as chlorophyll a, shows a winter maximum in the northern Benguela and a summer maximum in the southern Benguela. The lüderitz area shows perennial phytoplankon minima, possibly due to strong turbulence. The central Namibian shelf and the South African west coast shelf have persistently high phytoplankton biomass. A seasonal intrusion of warm oligotrophic water from Angola in late summer (December to March) results in strong contrasts between winter and summer in the extreme northern Benguela. Zooplankton biomass shows different cycles along the coast, with spring, summer and autumn maxima in the south, and a slight maximum during the second half of the year (July to December) off central Namibia. The dominant fish spawning period is spring-summer throughout the region. Long-term changes in the southern Benguela include a significant increase in zooplankton over the past five decades, with a decline since 1995. Fish abundance has declined in the northern Benguela but remained reasonably stable in the southern Benguela until 2000, when pelagic fish biomass increased dramatically with concomitant declines in zooplankton biomass. A range of modelling exercises, including expert systems, statistical models and linked IBM-hydrodynamic models, has been compared to or derived from field data, and has stimulated new observational programmes at improved space and time scales. Observational data at pertinent time and space scales are lacking in the northern Benguela system, which will hamper validation of prognostic and diagnostic models.
LOW variability in the Benguela is governed by varying scales of remote and local forcing linked to both Equatorial and Cape Basin systems. The nature of these nonlinea interactions is not clearly understood because scales are large and their elucidation through observational programmes alone is not cost effective. Models are required to characterise the complexity of the most important forcing and response scales in both time and space. It will be necessary to approach this as a multi-phase process, beginning with a diagnostic emphasis which evolves to a forecasting system through hindscating focussed specifically on large scale events of the past. It is clear that not all the variability scales are amenable to forecasting either because the driving process scales are too uncertain or because they are of little management of policy interest. Two scales were defined as being of interest to both these criteria: u • Short term (7 day) scale related to forecasting conditions leading to the walkout or mortality of rock lobster in the southern Benguela • Medium term (2 month) forecasting of the intensification of the remote forcing of ETSA derived LOW which has a bearing on the Namibian hake fishery These two scales are discussed in detail in the companion Chapter 13, this volume.
The European Union Gulf of Guinea collaborative research project on the impacts of environmental forcing on marine biodiversity was supported by the International Cooperation with Developing Countries Programme (INCO-DC). It was a natural sequel to three earlier international research projects on environmental variability and pelagic fishery resources in West Africa (Cury and Roy 1991; Bard and Koranteng 1995; Durand et al. 1998). At its conclusion, the project was able to provide an assessment of the impacts of upwelling and other forms of environmental forcing on marine biodiversity, with particular reference to demersal fish, and the basis for a fisheries information and analysis system for the sustainable management of fisheries in West Africa. It also facilitated the retrieval of important fisheries and survey data that had previously been inaccessible to scientists in the region. The major achievements of the project were presented at an international workshop on “Sustainable Management of the Fish Resources in the Gulf of Guinea” held in Accra in 1998.
In recent years, there has been a change in approach to the management of the world's natural resources from that of compartmentalised efforts focusing on maximising short-term yields and economic gain towards ecosystem management and long-term sustainability. A significant milestone was achieved in June 1992 when a majority of coastal nations adopted follow-on actions to the United Nations Conference on Environment and Development (UNCED) to: 1) prevent, reduce, and control degradation of the marine environment so as to maintain and improve its life-support and productive capacities; 2) develop and increase the potential of marine living resources to meet human nutritional needs, as well as social, economic, and development goals; and 3) promote the integrated management and sustainable development of coastal areas and the marine environment. Regrettably, the long-term sustainability of coastal ecosystems as a resource to support healthy economies of coastal nations appears to be diminishing. A growing awareness that the quality of these ecosystems is being adversely impacted by multiple sources of stress has accelerated efforts by scientists and programme managers to monitor, assess, and mitigate such stressors from an ecosystem perspective. The linkage between science and improved global stewardship of natural resources needs to be strengthened. An ecological framework that can serve as the basis for achieving the UNCED objectives is the large marine ecosystem (LME) concept. A description is given of an ecosystems approach being developed by United States National Marine Fisheries Service for strengthening science-based resource management using five linked modules for improving ecosystem sustainability: 1) productivity, 2) fish and fisheries, 3) pollution and ecosystem health, 4) socio-economic conditions, and 5) pertinent governance regimes. Examples are presented where the LME concept and the modular approach either are in use or about to be implemented.