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Abstract: Abstract Freshwater invertebrates and zooplankton (FIZ) play a key role in freshwater ecosystems and in food webs, but there is little research on their life cycle, ecology, and conservation. Therefore, this study focused on FIZ’ annual dynamics (abundance, diversity, and gross energy) in 30 ponds located in two wetlands: the Marais breton and Marais poitevin (Atlantic coast, France, Europe). These ponds had a FIZ abundance of 50,412 ind/m3 per site [range of 28,864–80,690] in a year. The study defined four typologies of ponds according to the environmental variables and the presence of some key FIZ taxa. The first group had a long flooding time, high silt content, and aquatic vegetation cover. The associated taxa were Chironomidae, Gammaridae and Atyidae. The second group of ponds had moderate slopes, high sand content in the sediment and a rich abundance of microcrustacea. The third group contained shallow ponds with soft slopes and a high aquatic vegetation cover (100%), which result in high FIZ diversity. Finally, the fourth group contained ponds with steep slopes, high silt content in the sediment, and Oligochaeta as the major taxon in this environment. Defining pond typologies based on environmental factors and FIZ is essential to adapting FIZ management and conservation measures implemented on ponds. In a context of global change, a reduction or even disappearance of FIZ communities would have a catastrophic impact on all faunal taxa dependent on FIZ as a food resource. PubDate: 2024-09-01
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Abstract: Abstract Ologe Lagoon, in Lagos State Nigeria, is one of the freshwaters exposed to chemical and hydrocarbon pollution. The impacts of anthropogenic pollution on lagoon microbial communities were assessed. Three sampling points were identified, namely Ologe industrial contaminated water (OLICW), Ologe human activity water (OLHAW), and relatively undisturbed water (OLPW). The microbial community structure of samples was determined via Illumina shotgun next-generation sequencing, while taxonomic classification was done by centrifuge. Acidic pH of (3.8 ± 0.02; 4.6 ± 0.01; and 6.5 ± 0.04) were observed for OLHAW, OLICW and OLPW. The heavy metals nickel and lead showed increase at OLICW > OLPW > OLHAW with their values higher than the WHO permissible limit. The gas chromatography flame ionization detector (GC-FID) fingerprints of the samples showed presence of aliphatic (nC1-nC17) and aromatic hydrocarbons like pyrene, anthracene, phenanthraquinone, and phenanthridine which is evidence of pollution. Structurally, the water metagenomes comprised of 40, 43, and 42 phyla, 67, 74, and 72 classes, 666, 982, and 920 genera from OLHAW, OLICW, and OLPW metagenomes. Dominant phyla across the three sites were Proteobacteria (37.1–64.1%), Actinobacteria (6.1–21.6%), Cyanobacteria (5.3–14.0%), Planctomycetes (6.6%), Firmicutes (6.6–5.7%). Archaea phyla like Euryarchaeota and Creanarchaeota were encountered. Principal component ordination (PCO) showed that OLHAW prokaryotic community had total variance of 88.2% PCO1 separating it from OLICW and OLPW, also OLICW and OLPW were separated by PCO2 accounting for 11.8% variation but clustered showing 60% similarity. The study showed abundance of Cyanobacteria, Nitrospira and Clostridia which are biological indicator of pollution and their presence signify eutrophication. PubDate: 2024-09-01
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Abstract: Abstract Desmids are usually abundant in shallow peatland pools. In these localities, water temperature is closely linked to seasonal fluctuations in air temperature, so with increasing temperature extremes in temperate ecosystems, these microalgae are exposed to conditions of high-temperature stress. We investigated whether the shape, size, and growth rates of Micrasterias thomasiana, a frequently occurring species, are associated with varying temperatures in cultures and natural populations. The research was based on parallel analysis of clonal populations in temperature levels from 13 to 33 °C as well as cells from natural populations collected during the season. The effects of high temperature on morphological plasticity and fluctuating asymmetry in the shape of cellular parts were investigated by the landmark-based geometric morphometrics. The results showed that variation among individuals and fluctuating asymmetry between the lateral lobes of Micrasterias cells increased at 29 °C and in natural samples taken in July and October. In parallel, the size of semicells growing at temperatures above 25 °C decreased compared to those grown at lower temperatures. However, the temperature effects on shape and size were not directly related to the growth rates. The overall bilateral asymmetry between semicell halves did not change in relation to varying temperatures. In general, the results showed that morphological variation in natural populations of M. thomasiana reflected seasonal cycles and corresponded to plasticity associated with temperature changes in clonal cultures. It might therefore be possible to use these phenotypic markers as indicators of thermal stress in natural populations inhabiting shallow pools in peatlands. PubDate: 2024-09-01
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Abstract: Abstract Macrophytes harbor numerous potentially invasive species that pose a threat to biodiversity and ecosystem services in freshwater environments. Egeria densa (Hydrocharitaceae) stands out as a prominent invasive species, recognized as a significant global invader across various ecosystems. In this study, we conducted an assessment of the genetic variability of this species in four Brazilian reservoirs, which are part of the species’ native range, employing the internal transcribed spacer (ITS) from the nuclear marker and the intergenic chloroplast marker trnL-trnF. The obtained sequences were then compared with those available in GenBank (NCBI). The results of our investigation revealed a low genetic differentiation among the sampled populations. For ITS and trnL-trnF, we identified four and three distinct haplotypes, respectively, with a predominant single haplotype shared by most specimens. Notably, we did not observe a discernible phylogeographic structure. The data we obtained represents the first sequences of E. densa within its native habitat, providing valuable insights on its genetic diversity and helping to understand invasive processes. PubDate: 2024-09-01
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Abstract: Abstract Aurantiochytrium sp. is a marine microalga known for its bioactive compounds. This study assessed its presence in Iran and investigated its specific biochemical and molecular traits. Parameters such as biomass, protein content, hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels, catalase enzyme (CAT) activity, and expression of malic enzyme (ME) and acetyl-CoA carboxylase (ACCase) genes were analyzed at different growth stages (24, 48, 72, and 96 h). Fatty acid composition, unsaturated fatty acids (UFA) and saturated fatty acids (SFA) contents, and the ratio of UFA to SFA were also examined. Molecular identification confirmed successful proliferation, with significant increases in biomass and protein content during growth. Elevated H2O2 and MDA levels indicated oxidative stress, whereas enhanced CAT activity suggested its potential role in scavenging reactive oxygen species and mitigating oxidative damage. The upregulation of ME and ACCase genes during growth indicated their involvement in lipid biosynthesis. This was further supported by the analysis of fatty acid composition, which revealed a higher proportion of UFA than SFA. These findings underscore the importance of specific growth stages for optimizing cultivation conditions and maximizing bioactive compound production in Aurantiochytrium sp. Overall, this study provides valuable insights into the growth dynamics and lipid metabolism of Aurantiochytrium sp., contributing to our understanding of its potential applications. PubDate: 2024-09-01
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Abstract: Abstract Protecting the ecological environment of the Yellow River Basin (YRB) is the key to promoting high-quality development of the whole YRB. Based on the information on environmental governance and the ecological environment in the YRB from 2016 to 2020, we constructed the regional eco-environment index (ECI) of the YRB, measured the government’s environmental governance capacity, and used the entropy weight method and relevant spatial statistical tools to reveal the spatial distribution characteristics of the ECI in the YRB. In addition, we used the method of configuration qualitative comparative analysis to explore the adaptation path of environmental governance for improving the ECI. The study showed that the regional ECI of the YRB was obviously heterogeneous, showing a spatial pattern of “good in the upstream, middle in the downstream, and depressed in the midstream.” There are three appropriate paths for environmental governance to improve the ecological environment: the government efficiency-oriented, rule of law-oriented, and pressure-oriented paths, among which the government efficiency-oriented path is the most common path. The findings propose the governance path of the ecological environment in the YRB from the perspective of configuration, reveal the configuration relationship among the factors affecting the government’s environmental governance, broaden ideas for solving ecological environment improvement problems in the YRB, and enrich the research methods of the government’s environmental governance. PubDate: 2024-09-01
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Abstract: Abstract Impact of habitat characteristics and anthropogenic activities on the distribution of macroinvertebrate traits and ecological preferences was assessed in Osun State, Nigerian. Physicochemical parameters involving water depth (WD), channel width (CW), flow rate, discharge, water temperature (W.T), dissolved oxygen (DO), total dissolved solids (TDS), electrical conductivity (EC), pH, biological oxygen demand (BOD), turbidity, nitrate, phosphate and organic matter (OM), were appraised, alongside macroinvertebrates from 5 streams in different geographical locations. Sampling spanned from December 2019 to October 2021, covering early and late dry seasons, as well as early and late rainy seasons. Principal component analysis classified the sites into three impact categories: least impacted (LIS), moderately impacted (MIS), and highly impacted (HIS). Nine traits and ecological preferences displayed significant variations alongside nine physicochemical variables, such as phosphate, OM, WD, discharge, CW, TDS, EC, W.T, and nitrate, within the Fourth-corner figure. Furthermore, these traits and ecological preferences exhibited notable correlations with site impact categories, including–no turbidity preference, spherical body shape, climbers to LIS, preference for transparent water, crawlers, climbers, burrowers, small body size to MIS, and highly tolerant to ocxygen depletion to MIS.This study underscores the effectiveness of macroinvertebrate trait-based approach as a freshwater biomonitoring tool in Osun State, Nigeria, providing essential insights into how environmental factors influence macroinvertebrate traits in lotic systems in the region, with implications not only locally but also for broader eclogical studies. PubDate: 2024-09-01
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Abstract: Abstract There is still a fundamental gap in our knowledge regarding the dormant egg bank in the littoral zone, as much of the existing information stems from studies conducted in the pelagic zone. We investigated cladoceran egg banks attached to macrophyte roots (Eichhornia azurea) and the soil surface collected from the littoral site of four Brazilian lakes. We test the hypothesis that sediment supports egg bank communities that are taxonomically distinct from those in macrophyte roots. We took replicate samples from paired examples of each egg bank and later incubated the diapausing eggs in a hatching experiment. Another aspect of our study involved classifying the egg bank community based on the traditional separation of cladocerans according to their microhabitat (pelagic vs. phytophilous). Results from the study indicated that the number of individuals and taxon richness was higher in the sediment egg banks than in those from the macrophyte roots in two of the lakes studied. The proportions of pelagic and phytophilous hatched varied between sediment and macrophyte roots egg banks within each lake studied. These findings partially supported our hypothesis that sediment contains taxonomically distinct egg bank communities compared to those in macrophyte roots. Our results suggest that the littoral zone, particularly the sediment habitat, may serve as a substrate for a persistent dormant egg bank of some pelagic cladocerans. Further comparative research among different macrophyte species and littoral sediments can help to gain more insights into cladoceran ecology and restoration programs for lakes experiencing environmental impacts. PubDate: 2024-09-01
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Abstract: Abstract The shallow Vrana Lake in Dalmatia, Croatia, is directly connected to the Adriatic Sea by the Prosika canal (0.85 km), constructed in the eighteenth century. The aim of this research was to examine the impacts of salinization on long-term changes in littoral macro-crustacean (Malacostraca) populations and assemblages in Vrana Lake and connecting canals. Benthic macroinvertebrates were sampled at seven sites during the period 2011–2020 (14 months) using a hand net (25 × 25 cm, 500 µm). During the study period, saltwater intrusions (strongest in 2012) through the Prosika Canal and site V4 caused increased salinization, resulting in a shift from normal oligohaline (0.5–5 PSU) to mesohaline (5–18 PSU) salinity. Out of a total of 18 macro-crustacean taxa identified, five widespread species—amphipods Echinogammarus stocki and Gammarus aequicauda, isopods Lekanesphaera hookeri and Proasellus coxalis, and decapod Palaemon antennarius constituted 91.6% of collected specimens (26,986). The first three brackish/marine species were significantly positively correlated with the average salinity 12 and 24 months before sampling. They disappeared or had very low abundance during the second low salinity phase (< 1–2 PSU), when freshwater/oligohaline P. coxalis and P. antennarius were the dominant macro-crustaceans. Two years of low salinity were needed for a strong population decline or disappearance of three brackish/marine species. Salinization is a major stressor in the Vrana Lake basin, and measures for its active control are urgently needed. The use of tested macro-crustacean metrics is recommended for future ecological monitoring as it could provide fast information about the effects of water management on aquatic biodiversity. PubDate: 2024-09-01
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Abstract: Abstract Thermal pollution in the riverine resources is an important issue due to its potential threat concern towards aquatic organisms. Though the thermal pollution effect on the planktonic community is well studied in the coastal thermal plant, little is available in freshwater stretches of river ecosystems. The goal of the current study was to ascertain the impact of thermal discharge from a coal-fired power station on the planktonic population and water quality along the spatial and temporal dimensions of a tropical river Ganga River. Thermal discharge led to a thermal gradient with an increase in water temperature in the river near the discharge point. The effect of temperature elevation was more profound in winter than the summer. The results showed that the dissolved oxygen and chlorophyll content was lower (1.46 and 1.34 times, respectively) near the thermal discharge point particularly in the winter as compared to summer. A total of 28 phytoplankton genera from 9 classes were identified among which 5 and 3 genera are dominated in winter and summer, respectively. The thermal discharge resulted in 1.34 times reduced chlorophyll content at the source in the winter, whereas no effect was observed in the summer. However, the diversity and abundance of plankton were found to be more closely connected to seasonal variation than to the thermal gradient. This study inferred that the plankton assemblage pattern at the thermal discharge point in the tropical river was more influenced by seasonal variation than the thermal discharge. Further studies are required on other aquatic biota for a comprehensive understanding of the effect of thermal pollution on river health status. PubDate: 2024-09-01
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Abstract: Abstract Worldwide freshwater salinization may significantly alter ecosystem functioning and affect biodiversity. We studied the effect of salinity on hatching success of resting eggs of different ages and life history traits of post-diapause females of cladoceran Moina macrocopa. The hatching success of resting eggs was almost unaffected by the salinity we tested (up to 5.9 g L−1). We observed a distinct difference in the hatching success of resting eggs of different ages, which was lower by ca. 50% for 4-year-old resting eggs compared with 1-year-old resting eggs. We found a decrease in the values of the life-history traits of the females hatched from 4-year-old resting eggs compared with the females hatched from 1-year-old resting eggs exposed to salinity within the range of 0.08–3.5 g L−1: a shorter lifespan, a lower juvenile somatic growth rate, a delay in the day of the first reproduction, and a smaller number of parthenogenetic clutches produced. Analysis showed that at a salinity of 3.5 g L−1, females hatched from resting eggs are more vulnerable to the effect of salinity than directly developing females. The post-diapause females exposed to salinity showed a shorter lifespan and reduced reproduction parameters (produced fewer clutches and neonates) compared with the directly developing females. Thus, the hatching of resting eggs can be considered as a critical period of the development of a species with the diapause in its life cycle due to the vulnerability of post-diapause females to increased salinity, which can be crucially important for the ecological success of the population. PubDate: 2024-09-01
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Abstract: Abstract The diversity of Ostracoda in Central Serbia is relatively unknown. With the aim of exploring this diversity, and increasing the overall knowledge on their ecology, this study was carried out over a mountainous area in Central Serbia and some parts of the Vojvodina province. In total, 46 samples were collected from 36 water bodies, with several different habitat types. Ostracods were present in 22 of those water bodies, at 27 sites. A total of 17 species were recorded, six of which are new additions to the fauna of Serbia. A multivariate analysis (Canonical Correspondence Analysis) of ostracod communities and their relationship with measured environmental factors is given, with four out of five measured environmental factors showing a significant relationship with the distribution of recorded species. These were water temperature, altitude, electrical conductivity and dissolved oxygen, while pH was not significant. A cluster analysis (UPGMA) of the samples in which ostracods occurred was also performed using Jaccard distances. It grouped samples into 7 clusters, primarily defined by presence/absence of certain species. In addition, the proportion of non-cosmopolitan ostracod species was calculated for each sample, as well as for geographically grouped samples, to investigate if the percentage of non-cosmopolitan species potentially correlates with the observable state of sampling sites, mainly in terms of anthropogenic pressure and/or habitat degradation. PubDate: 2024-09-01
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Abstract: Abstract The Transbaikalia (Russia) hosts a number of shallow endorheic saline alkaline lakes. The outcome of our studies demonstrated changes in phytoplankton and zooplankton in selected lakes covering a wide salinity gradient (from 0.69 to 128.33 g/L) over a number of years. Our main goal is to assess the variability of structural and functional indicators of phytoplankton and zooplankton communities at the various salinity levels. The gradient of abiotic factors significantly determines the dynamics of planktonic community diversity, abundance, biomass, and production. High values of secondary production was ensured by nonpredators (bacteriovorous, herbivorous, and detrivorus). We found that species and functional diversity of phytoplankton and zooplankton decrease with increasing salinity, whereas their abundance, biomass, and daily secondary production did not. In phytoplankton, a shift occurred from the small-medium cell size unicellular and colonial non-flagellated forms to the large-extra large filamentous cyanobacteria and colonial algae. A shift from selective raptorial and microphagous carnivores to herbivorous copepods and cladocerans and further to more generalist filter-feeder of rotifers and anostracans was observed in zooplankton. These findings are important because they provide a meaningful view of phytoplankton-zooplankton trophic interactions and contribute to an improved understanding their functional effects on aquatic ecosystems. Our results also complement existing knowledge and provides new information about the diversity and functioning of planktonic communities in soda lakes. PubDate: 2024-09-01
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Abstract: Abstract Seasonal variations of limnological parameters and phytoplankton dynamics in high-altitude oligotrophic lakes form a critical area of interest in assessing the implications and impact of climate change on fragile ecosystems and formulating effective conservation strategies. Thus, a study was conducted by sampling water from five High-Altitude Lakes (HALs) of Tawang district, Arunachal Pradesh between December 2019 and December 2021. The seasonal variations of seven physico-chemical parameters and phytoplankton's composition, distribution, and seasonal abundance were assessed. Further, the diversity, dominance, and evenness of phytoplankton were estimated and the relationship between limnological parameters and the phytoplankton species was established using Canonical Correspondence Analysis (CCA). The limnological parameters such as pH, dissolved oxygen, free carbon dioxide (FCO2), alkalinity, hardness, conductivity, and total dissolved solids (TDS) show significant seasonal variations among the HALs. A total of 50 phytoplankton species belonging to 8 Class and 33 Family were recorded. The order of phytoplankton dominance was Bacillariophyceae > Cyanophyceae > Zygnematophyceae > Chlorophyceae > Chrysophyceae = Dinophyceae, Euglenophyceae = Klebsormidiophyceae. The most abundant species were Cymbella sp., Gomphonema sp., Fragilaria sp., Navicula sp., Nitzchia sp. (Bacillariophyceae), Volvox sp., Pediastrum sp., Microspora sp. (Chlorophyceae), Oscillatoria sp., Lyngbya sp., Calothrix sp., Chroococcus sp. (Cyanophyceae), Spirogyra sp., Mougeotia scalaris, Cosmarium sp., Closterium sp. (Zygnematophyceae). The abundance of phytoplankton species varied seasonally with most copious in winter. The distribution, abundance, and diversity of phytoplankton were largely influenced by pH, hardness, FCO2, conductivity, and TDS levels. So, the findings of the study could be helpful in exploring the potentialities of introducing cold-water fisheries in HALs to ensure food security under climate change scenarios. PubDate: 2024-09-01
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Abstract: Abstract In arid zones, ephemeral rock pools exhibit cyclical and unpredictable hydroperiods, which entail long periods of drought and short periods of flooding. The hydrological perturbations associated with the dry phase could potentially trigger abrupt changes in the structure and dynamics of the communities in temporary ecosystems. Our main objective was to investigate the processes shaping phytoplankton communities, driven by local environmental variables, spatial distribution (urban and protected rock pools), and the hydrological regime (different phases), with a focus on disturbances over space and time. The hydrological regime was irregular throughout most months, characterized by three phases distributed in rainy and dry periods. Phytoplankton biomass was higher in urban rock pools in the dry period, and analyses indicated that community structure was influenced by the local variables as temperature and total dissolved solids, by temporal phases and by spatial factors. Replacement contributed more to overall community dissimilarity than nestedness. Overall, the results highlight the role of environmental fluctuations and human pressure in urban rock pools, in structuring phytoplankton communities. PubDate: 2024-09-01
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Abstract: Abstract Sagartaal is located in Budaun with geographical coordinates 28.0512°N and 79.1305°E in Nawada region, Uttar Pradesh, Uttar Pradesh, India. Understanding the composition, diversity, and abundance of the zooplankton is vital for better utilization of such waterbodies. The present study was carried out from October 2022 to September 2023. A total of 24 species belonging to 16 species of Rotifera, 4 species of Cladocera, 2 species of Copepoda, and 2 species of Ostracoda were recorded. The prominent species were Brachionus forficula, B. calyciflourus, Keratella cochlearis, Simocephalus sp., Cyclops sp., and Mesocyclops sp. Zooplankton showed seasonal variations in their species composition, abundance, and diversity concerning water temperature, pH, total alkalinity, dissolved oxygen, and hardness. The zooplankton density was recorded as maximum in winter and minimum in monsoon. Statistically, zooplankton shows significant correlations as Rotifera with EC, BOD (r =− 0.50; − 0.58, respectively); while with total hardness (r = 0.75); Cladocera with DO (r = 0.53), alkalinity (r = 0.57), nitrate (r = 0.56), and phosphate (r = − 0.49). The highest Shannon index (2.83) was obtained for summer, due to the lowest value of the dominance index (0.07) for this season. More studies are warranted on Monitoring such ecosystems as Sagartaal to understand the effects of anthropogenic pressure on zooplankton's community structure, can help in identifying the indicator species to formulate effective conservation planning. PubDate: 2024-06-20
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Abstract: Abstract Periphyton is an important basal food source for many aquatic consumers by directly or indirectly providing long-chain polyunsaturated fatty acids (LC-PUFA). Although periphyton LC-PUFA content is highly sensitive to aqueous nutrients, the majority of prior studies have been conducted in low-nutrient aquatic environments. Less is known about how periphyton LC-PUFA content may change in response to higher nutrient concentrations in rivers. We conducted a periphyton culturing experiment by manipulating a gradient of aqueous nutrient concentrations from 0.002 to 0.18 mg P/L to investigate how aqueous nutrients affected periphyton FA from oligotrophic to eutrophic waters. Our results showed a significant curvilinear relationship between aqueous water nutrients and periphyton FA. In oligotrophic conditions, periphyton LC-PUFA increased as aqueous nutrients increased, whereas in eutrophic waters, periphyton LC-PUFA decreased as aqueous nutrients increased. The change of taxonomic composition, especially the increase of diatom density, was a significant factor influencing periphyton LC-PUFA content. Additionally, periphyton biomass experienced a significant increase with elevated aqueous nutrients, which differed from periphyton LC-PUFA. Our study detected the response of periphyton FA to aqueous nutrients from oligotrophic to eutrophic conditions, and provided a reference for the protection of river ecosystems. PubDate: 2024-06-19 DOI: 10.1007/s10452-024-10115-4
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Abstract: Abstract Rivers interlinking by transposition projects have multiplied in the world, altering the landscape and flow regime of continental water systems. Recently, an intermittent river in northeastern Brazil has been artificially connected to the São Francisco River basin in a water transfer project. Thus, this study aims to provide an inventory of the fish parasites from the Jaguaribe River basin in the scenarios of pre- and post-transposition, and to evaluate the short-term impacts on the parasite fauna. Of the analyzed fishes, belonging to 31 species, about 30% were parasitized. A total of 47 parasite taxa were recovered, including monogeneans (17), digeneans (9), nematodes (9), acanthocephalans (3) and crustaceans (6), and unidentified cysts of Acanthocephala, Cestoda and Digenea, representing the description of 30 new geographic records and 104 new parasite-host associations. By expanding the range of the geographic distribution of fish parasites and increasing the list of hosts, the study contributes to the knowledge of fish parasites biodiversity in the semi-arid region of Brazil and in the Caatinga domain. Considering all parasite species, significant differences were observed in total prevalence, total mean abundance, diversity index and host specificity index; the highest values of total prevalence and total mean abundance were observed in the post-transposition, while the diversity index and host specificity index was higher in the pre-transposition period. This is the first study evaluating fish parasites before and after a major water transfer event and the results will allow further evaluation of middle and long-term changes in the specific composition of fish and parasites from the receiver drainages. PubDate: 2024-06-07 DOI: 10.1007/s10452-024-10112-7
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Abstract: Abstract The reproductive strategies of species play a fundamental role in formulating effective management plans and maintaining local community structure and ecological balance. This study investigated the reproductive characteristics of two sympatric species, Callinectes danae and Callinectes ornatus, in Atlantic waters. Monthly sampling was conducted from July/12 to June/14 in the coastal (sites: S1, S2, S3 and S4) and estuarine-lagoon (sites: S5, S6 and S7) areas of Cananéia-Iguape, Brazil. Significant differences in allometric coefficients were observed, particularly in the relationships chelipod length vs. carapace width (CW) for males and abdominal width vs. carapace width (CW) for females. Morphological sexual maturity was estimated at 58.8 mm CW for C. danae males, 54.5 mm CW for females, 45.0 mm CW for C. ornatus males, and 41.2 mm CW for females. Gonadal sexual maturity sizes were identified at 69.4 mm CW for C. danae males, 61.4 mm CW for females, and 58.4 mm CW for C. ornatus males, 46.9 mm CW for females. Both species spawn predominantly during the austral summer, with higher prevalence in site S5 for C. danae and S1 for C. ornatus. Recruitment occurred in austral spring and summer, with C. danae concentrated in estuarine-lagoon regions and C. ornatus along the coast. Reproductive patterns of C. danae were associated with temperature and salinity, while C. ornatus exhibited correlations with temperature and organic matter. This study highlights the influence of environmental factors on species' life cycles. Furthermore, it contributes to the evaluation of management and monitoring strategies, recognizing the economic and ecological significance of these species for sustaining these ecosystems. PubDate: 2024-06-07 DOI: 10.1007/s10452-024-10118-1
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