Declining Fish Stocks Research Articles

Challenges of regulating commercial use of marine elapid snakes in the Indo-Pacific.

Marine elapid snakes are a diverse, predominantly Indo-West Pacific species group. The persistent removal of some species has an unquantified but potentially dire impact on populations. We conducted the first comprehensive review of the trade in marine elapid snakes based on published literature (1974-2022) and trade data from the only species (i.e., Hydrophis [Lapemis] curtus) whose trade is monitored internationally. Some species and populations were subjected to targeted harvest for their meat and skins for at least the last century; fisheries are possibly the most significant threat to populations of marine elapids, with the highest numbers being exploited either accidentally, incidentally, or opportunistically in Southeast Asian fisheries targeting other seafood, including demersal trawl and squid fisheries. Southeast Asia is the core region for exploitation of marine elapids. Annual offtake is >225,000 individuals of at least 8 species in the Gulf of Thailand. Of 72 recognized marine elapids (all non-CITES [Convention on International Trade in Endangered Species of Wild Fauna and Flora] species), Hydrophis curtus and Hydrophis cyanocinctus dominate the skin trade. Skins of H. curtus are traded mainly in East and Southeast Asia and, to some extent, Europe. Despite some baseline information on the trade of these species, the sustainability of their harvests, particularly in the context of the burgeoning and unmanaged nature of fisheries in the region, remains the major challenge. In an era of declining fish stocks, there has been an increasing trend to commercialize the harvest and use marine elapids that were once considered accidental bycatch and discarded. This trend will continue to pose a significant risk to these snakes unless appropriate fisheries and trade regulations are enforced. Applying the precautionary principle to prevent the overexploitation of sea snakes is an indispensable measure in which trade in regional populations should be regulated through CITES. Accordingly, management plans to identify core distribution regions of exploited species would be crucial for assigning national responsibilities to sustain species and populations in the long term.

Genetic Diversity and Population Structure of Amphidromous Goby (Stiphodon semoni) in Western Part of Southern Java Waters

Graphical Abstract Research Highlight The genetic diversity of Stiphodon semoni is high. All populations have high haplotype diversity except for Cimaja. No genetic structure is observed within the populations of semoni. The population of semoni has undergone demographic expansion. Cibareno River has the potential to be a protected area. Abstract Fishing activities negatively impact fish populations, potentially causing a decline in fish stocks. Nevertheless, ensuring diversity and connectivity among populations can mitigate these adverse effects. To evaluate the connectivity of river mouths in the western part of Southern Java waters, we sequenced forty Stiphodon semoni individuals from five populations using mitochondrial cytochrome oxidase subunit 1 as molecular markers. The study revealed that S. semoni populations showed high diversity (0.821), with the population in Cimaja displaying the lowest diversity (0.464). Furthermore, the result of the analysis of molecular variance was a Fst value of 0.0630 with a p-value of 0.22. These results along with the result of the haplotype network indicated no significant genetic differences among these populations. This implies that the river mouths in the western part of Southern Java waters are interconnected. The distribution of mismatches showed a single peak, indicating that the populations have undergone demographic expansion. This information could be valuable for the conservation and management of S. semoni in the western part of the Southern Java waters.

Effectiveness of textured vegetable protein incorporation for partial fish meat substitution in fish cakes

SummaryExcessive consumption of seafood has resulted in a decline in fish stocks and the destruction of ecosystems worldwide. Textured vegetable proteins (TVPs) can be used in manufacturing fish products, including surimi‐based fish cakes, to prevent these problems. In this study, we aimed to incorporate TVP into fish cakes as an alternative to fish meat (surimi). Fish cake samples containing TVP (0, 5%, 10%, 15% and 20%) were prepared and cooked through boiling or frying. Texture profiles, volatile compounds and consumer acceptance of the fish cake samples were measured. An increase in TVP content enhanced the protein content of the samples, making them more suitable than fish meat is as a protein source. In the fish cake samples, the textural properties, including hardness, springiness, cohesiveness, gumminess and chewiness, increased with increasing TVP content. Analysis of the volatile compounds showed that hexanal and 2‐pentifuran, which are primarily responsible for the grassy or beany flavour of soy, increased with increasing TVP content in fish cakes. The levels of these components were significantly lower in the fried samples than in the boiled samples. Overall, fried fish cakes containing 5% TVP (FST5) exhibited acceptance ratings similar to those of the control. Moreover, FST5 scored the highest in appearance, odour, taste and overall liking. Therefore, fried fish cakes supplemented with 5% TVP were qualitatively similar to fried fish cakes containing 100% fish meat (surimi). We propose the partial substitution of fish meat with alternative products to potentially reduce overfishing.

Evaluating coastal lagoon sustainability through the driver-pressure-state-impact-response approach: a study of Khenifiss Lagoon, southern Morocco

Coastal lagoons are valuable ecosystems, providing socioeconomic benefits and supporting human populations and biodiversity. However, these systems face several challenges, making them vulnerable to both natural and human factors. In this study, we apply the Driver-Pressure-State-Impact-Response (DPSIR) Approach to conduct a comprehensive socioeconomic and environmental assessment of the Khenifiss Lagoon to promote sustainable development and support decision-makers. Located on the southern Atlantic coast of Morocco, the lagoon was designated a natural reserve in 1962, a biological reserve in 1983, and a protected wetland under the Ramsar Convention since 1980. This study represents the initial endeavor to conduct a comprehensive global and multidisciplinary environmental assessment of the lagoon by using a wide range of data sources, including relevant publications and reports, satellite images and remote sensing data, field observations, and interviews, all analyzed under the DPSIR framework. Our findings show that both natural and human factors have an impact on the ecosystem. Natural Factors associated with the geomorphological features of the region likely contribute to the silting of the lagoon, possibly intensified by a large shipwreck stuck at its inlet. Meanwhile, human factors encompass population growth (at a rate of 2% per year), tourism, shellfish farming, fishing, shellfish harvesting, and salt extraction. Our results reveal significant changes in the lagoon’s condition in recent years, including a reduction in water body extent, a probable decrease in depth, and an increase in the accumulation of solid waste, plastics, and wastewater in three sectors spanning a total surface area of 464 ha (equivalent to 7% of the lagoon), a substantial expansion of the salt mining area encompassing 368 ha, and a remarkable loss of biodiversity, manifested in declining fish stocks and seabird populations. This study showed that the lagoon is positioned as a potential site for economic growth and serves to alert stakeholders and the local population to the ecosystem’s environmental issues. Based on the findings of this study, we highly recommend regulating human activities within the lagoon, the removal of the wreck at the entrance, proper waste management, community awareness programs, and strict monitoring and enforcement of regulations to protect the environment.

Implications of fisher perceptions on coral restoration in Tondol, northwestern Philippines

Increasing coral restoration efforts globally have been aimed at improving reef status and the ecosystem functions and services they provide, including enhancing reef fish communities and fisheries production on nearby reefs. However, empirical evidence showing the influence of coral restoration on fish stocks is limited. In Barangay Tondol, a small-scale fishing village in the northwestern Philippines, fisher knowledge and perception studies were completed through individual interviews to provide insights into the perceived impacts of local restoration efforts on coral reef conditions and fishery outputs. The influence of fishers' social demographics and fishery information to their held perceptions were also explored. Fishers’ responses showed a perceived decline in fish stocks over the last 5–10 years mainly attributed to overharvesting, and a slight improvement in coral reef condition due to a reduction in destructive fishing. Out of 53 fisher respondents, 72% were aware of coral restoration efforts in their area and held positive perceptions that theoretically, conducting coral restoration can improve their fish stocks and local reef conditions through the provision of habitat functions. Perceived actual effectiveness of the local efforts was also positive, but with a lower number of responses. Multiple hierarchical regression tests showed that, among social demographics, fishery information, and perceptions on fish stocks, perceived improvement in coral condition was associated with stronger support for coral restoration activities. These findings indicate that fishers perceive positive effects of coral restoration to local coral status and fisheries, and highlight the need for restoration practitioners to engage early on with key stakeholders to assess local fisheries status and local priorities to inform restoration strategies.

Addressing conflict between fishermen and the Titicaca Grebe (Rollandia microptera) through diet analysis

Human–wildlife conflict is often a driver of species declines, and understanding the material basis of this conflict is the first step in addressing it. The Titicaca Grebe Rollandia microptera is an endangered endemic species found solely in the Lake Titicaca watershed of Peru and Bolivia, and has experienced population declines due to fisheries bycatch. Human fishers often have negative opinions of the Titicaca Grebe, because they consider it as a competitor for declining fish stocks. We tested that assumption by an analysis of the bird's diet and found that the Titicaca Grebe does not compete with fishers for more lucrative fish species such as trout Oncorhynchus sp. and Pejerrey Odontesthes bonariensis, but does compete for the less desirable (to human fishers) native Orestias sp.

Sistem Sosial dan Ekologi Pantai Batu Pinagut

The interaction of social-ecological systems in coastal villages often causes problems, ranging from decreasing ecological quality to social conflict. This research aims to determine the description of the social interaction system in the coastal area and to determine the description of the ecological system in the coastal area of Kuala Kaidipang Village, North Bolaang Mongondow Regency. The data used is secondary data obtained by direct observation. The research results show that the separation between social and ecosystem management causes a decline in small-scale fisheries production on the coast due to a decline in fish stocks. The decline in fish stocks is caused by overfishing, habitat degradation and pollution. Open access further exacerbates the problem of overfishing. Managers and stakeholders face difficulties in designing and implementing effective management solutions. As for social interaction, it can be seen from 2 aspects, namely close relations between residents, interaction with the natural environment and coastal activities. Meanwhile, the ecological system includes coastal ecological systems including marine biodiversity, mangrove ecosystems, human activities and sustainability.

RELEVANCE OF DATA ANALYTICS IN SUSTAINABLE FISHERIES MANAGEMENT: AN EVIDENCE-BASED STUDY

Aim of the study: The value of fish resources to socioeconomic development is immense. However, there is growing evidence that loss of quality in the marine environments e.g. marine waters at sea and coastal freshwater zones is threatening the availability of livelihood resources e.g. fish resources evidenced by the dwindling fisheries resources that promote sustainable livelihood. Cognizant of this, several fisheries institutions, governments, and local users have come up with several strategies to boost marine water environment management and promote sustainable fishing. Unfortunately, most of the initiatives have not fully managed to repulse unsustainable practices e.g. marine water pollution that leads to loss of wild catches and leads to unsustainable fishing practices. Material and methods: Owing to this we use a mixed research methods approach involving a systematic literature review and field survey in Alappad to argue and present a case for governments and fishery management organizations to invest in data analytics as a new pathway that can give a comprehensive, near real-time view of both ocean resources and coastal fishing activities in light of the declining fish stocks and escalating environmental problems e.g. marine water quality loss e.g. due to pollution. Results and conclusions: Findings documented that by using data analytics, governments, and fisheries management organizations/individuals may respond more swiftly to external forces like climate change, and marine water quality loss and implement new policies and regulations thus promoting sustainable fisheries management. Local perspectives of coastal communities could also guide the best data analytics tool or method to be used.

The Unpronounced Support: Wives’ Engagement in Sustaining Fishers’ Households Enterprises in the Fishery Challenging Space in Kilwa Kisiwani, Tanzania

In contrast to convenient and easily accessible productive domains such as agriculture, where women’s participation is deemed indispensable and visible, their engagement in households’ fishing enterprises has been grossly undervalued. However, the 2021 Kilwa Kisiwani study found that fishermen’s wives were vital to their families’ fishing businesses in the face of declining fish stocks and government moratoriums. This cross-sectional study that involved 221 respondents targeted fishing-dependent households where both husbands and wives were involved, with the latter making a substantial amount. Data gathering, analysis, interpretation and discussion employed qualitative and quantitative methods. The findings indicate that most households’ fishing enterprises survived because spouses provided labour, worked outside the home or supported the enterprise from home. The paper cautions against the notion that male dominance invariably determines the socioeconomic trajectory of households while women are relegated to subordinate roles. This perspective is deemed an oversimplification and a distortion of reality.

Investigation of Traditional Fishermen's Income in Labuhan Bilik Village, Panai Tengah District, Labuhan Batu Regency

This research aims to reveal and analyze the income of traditional fishermen in Labuhan Bilik Village. The research methods used are surveys, interviews, and data analysis. The data collected includes fishermen's income, sources of income, equipment used, and challenges faced. The research results show that traditional fishermen's income comes from several sources, including fish catches, seafood, and side jobs such as agriculture. Although fishermen's income varies throughout the year and is influenced by weather factors, fish catches remain their main source of income. The main challenges traditional fishermen face in this village include climate change, declining fish stocks, and competition with commercial fishermen. It provides a basis for developing policies that support the fisheries sector in the region.

Artisanal Inland Water Fishing and Challenges of Livelihood Sustainability in Ibi Local Government Area, Taraba State Nigeria

This study examined challenges of livelihood sustainability from artisanal inland water fishing activities in Ibi LGA, Taraba State, Nigeria. Descriptive survey design was adopted. Purposive sampling was used in selecting 406 respondents from 12 communities in 6 political wards of the LGA. Descriptive statistics was used to analyse 401 questionnaires retrieved. Findings of the study reveal decline in daily fish catch from three baskets 10 years ago to only one basket presently. Also, income from fishing has declined from ₦150,000 ($192) monthly 10 years ago to less than ₦50,000 ($64) presently. Factors responsible for decline in fish catch include rising water level, temperature increase, pollution, climate change, seasonality and unsustainable fishing practices. The unsustainable fishing practices include use of chemicals, small size nets and mosquito nets in fishing. The results reveal that fishermen engaged in non-fishing activities, fish farming and construction of fishing ponds along the floodplain as a way of achieving livelihood sustainability. Challenges of livelihood sustainability include seasonality of fishing activities, decline in fish stocks, use of traditional fishing methods and unsustainable fishing practices among others. The study recommend the need to enforce extant laws on fishery protection, enlightenment campaign, and government support to fishing cooperatives.

Climate change adaptation strategies for small-scale Hilsa fishers in the coastal area of Bangladesh: social, economic, and ecological perspectives

This study examines social, economic, and ecological adaptation strategies for small-scale Hilsa fishers in Bangladesh’s coastal areas in response to the impacts of climate change. The Hilsa fishery and the communities dependent on it are vulnerable to the adverse effects of climate change, making it imperative to adopt mechanisms to cope with its consequences. Using a mixed-method approach, including in-depth interviews, focus group discussions, and a review of secondary resources, this study explores adaptation policies, relevant factors, and aspects of the Hilsa fishing community’s response to climate change. The study finds that climate change poses a significant threat to biodiversity, potentially leading to changes in fish migration systems and declining fish stocks. The Hilsa fishers perceive that addressing climate change requires policies that combat poverty, preserve or restore biodiversity, and enhance ecosystem services simultaneously. The study identifies social adaptation strategies such as risk reduction, social relationships, and participation in adaptation planning. Economic adaptation strategies include alternative livelihood development, aquaculture, and access to credit. The study also suggests that effective ecological adaptation actions include developing climate change knowledge and fishers’ local ecological knowledge, establishing more effective sanctuaries, and developing networks among protected areas. The study concludes that formal adaptation policies should consider fishers’ interests and practices for adaptation, including their knowledge of social, economic, and ecological issues, to address the impacts of climate change on small-scale fishers and their communities.

The significance of the Sikunga Fish Protected Area towards fisheries conservation in the Zambezi River, Namibia

AbstractLarge cichlids of the genera Oreochromis, Tilapia, Serranochromis and Sargochromis are the backbone of the gillnet fishery of the Zambezi River, but Oreochromis spp. is currently over‐exploited and at risk of local extinction. As a result, the Sikunga Fish Protected Area was established in 2012 to restore a decline in fish stocks of the Zambezi River, but its efficiency has never been assessed. The aim of this study was to compare fish assemblages, abundance and mean sizes between a fish protected area (Sikunga FPA) and nonprotected areas; the Sikunga Buffer Zone and the Lisikili Fished Area on the Zambezi River. Monthly gillnet surveys, using commercial gillnets, were conducted from July to December 2020. Overall catch rate (CPUE) by weight of all species differed significantly among the sampling sites (Kruskal–Wallis H‐test, range χ2(2) = −27.95, p = 0.0001). The highest CPUE was recorded at Sikunga Fish Protected Area (2.85 kg/set ± 0.42 (SE)), followed by the Sikunga Buffer Zone (0.93 kg/set ± 0.16 (SE)) and the Lisikili Fished Area (0.61 kg/set ± 0.14 (SE)). Further analyses showed that the mean sizes of O. andersonii, Coptodon rendalli, Serranochromis and macrocephalus were significantly larger at the Sikunga Fish Protected Area than at the Lisikili Fished Area. A particularly interesting observation pertains to a lack of variation in catch rates of Serranochromis macrocephalus and mean sizes of Clarias gariepinus between the protected and nonprotected areas, signifying that fish protected areas can be species‐specific, and not all species in a water body will respond positively to protection. The overall results of this study support the innovation of fish protected areas as a fundamental tool in attaining sustainable management of fishery resources in inland waters of Namibia and other developing countries.

Proposed Solutions to the Problems of the Lake Chad Fisheries: Resilience Lessons for Africa?

Fishing communities in Lake Chad are experiencing humanitarian crises—more than five million people in the region are hungry and malnourished—and fishers are in dire need of improved fisheries management policies. Understanding the fishers’ resilience, and how they perceive their fisheries policies, could provide an opportunity for governments and fisheries managers to refine their policies. The present study, which is based on 38 semi-structured interviews carried out between January and April 2022 on the Nigerian shores of Lake Chad, breaks new ground, firstly by seeking to understand the issues raised by declining fish stocks in Lake Chad from the viewpoints of fishers themselves; and secondly by making use of resilience theory to interpret the fishers’ responses to their situation. Our findings are that the fishers have a surer grasp of the most effective resilience strategies available to them than external bodies; and that the fishers’ adaptive resilience and local knowledge provide a framework for developing smarter fisheries management policies for Lake Chad. This study provides evidence to support recommendations for Africa’s supranational, national and local governments to invest in, and make use of, the fisheries research on the ground to address the problems facing its fisheries, rather than experimenting with seemingly random ideas from across the globe. The Lake Chad fisheries crisis is an extreme case demonstrating the harmful effects of external influences from which the fisheries of other African countries can learn lessons.

Unlocking the blue economy: financing a sustainable ocean future

The world’s oceans are integral to the livelihoods, food security, and economic well-be- ing of billions of people around the world. More than three billion people, roughly 40% of the global population, reside in coastal areas and rely on the ocean as a fundamental source of their livelihoods [1]. Meanwhile, industries such as tourism, fisheries, marine transportation and petroleum-related to the ocean economy play a key role in global economic expansion and climate action [2], [3]. Despite the immense value of the ocean, marine ecosystems face many threats, including climate change with rising sea levels and ocean acidification, pollution from natural and anthropogenic sources, unsustain- able fishing practices depleting fish stocks, and coastal development [4], [5]. For exam- ple, in the Sri Lankan context, the X-Press Pearl ship accident has caused enduring dam- age to the local coastal and marine ecosystem. The contamination of these ecosystems with hazardous materials and plastic pellets has led to a sustained decline in fish stocks, adversely impacting the fishing industry. The Sri Lankan eco-tourism has also experi- enced long-term declines in tourism revenue. The lasting health risks associated with pollutants threaten both marine life and communities dependent on the ocean

Understanding EU Fisheries Management Dynamics by Engaging Stakeholders through Online Group Model-Building

The Common Fisheries Policy (CFP) has a challenging mandate to find the right policy mix to simultaneously achieve all three aspects of sustainability: economic, social, and environmental. But development and implementation of an effective and sustainable fisheries management policy has been a challenge all over the world. The evidence of this failure is found in the continuous decline in fish stocks. Faced with the difficulty in fulfilling this mandate, the European Commission has increasingly been embracing fisheries stakeholders’ involvement. Stakeholder involvement in policy development and implementation is important because it tries to bring the relevant interested parties together, understanding and paying attention to what is important to each and every stakeholder, identifying the individual and common issues. This process in turn can foster connections, trust, confidence, and buy-in, and commitment for the implementation of the policy. This research describes a group model-building (GMB) approach using system dynamic methodology as a participatory model building tool, enabling stakeholders to become deeply involved in the identification and modelling of the complex issues faced by the EU fisheries. Given the geographical diversity of the stakeholders, GMB was applied online, both synchronously and asynchronously, providing participants time to carefully reflect on key variables, their relationships, and the behaviour of the overall system. The study demonstrated the need and relevance of an adequate engagement of the stakeholders, with online stakeholder consultation proving an effective method of engagement. Hence, the study is very relevant for both scientists and managers. The GMB process meant the final model evolved significantly from the initial one offered, which pointed to active involvement in and progressive learning from the modelling process itself, as the methodology argues. Two quantitative stock-flow models using actual numbers were built not only to aid the GMB process but to depict how all three aspects of sustainability could actually be met with the right set of policies that consider feedback loops and inherent trade-offs.

Alleviating impacts of climate change on fishing communities using weather information to improve fishers’ resilience

This study contributes new knowledge in evaluating actions aimed at alleviating impacts of climate change on small-scale fishers and enhancing resilience in their households in West Africa. Evidence of the damage caused by climate change to the artisanal fisheries sector in West African countries is accumulating. Current measures in place for artisanal fishers to adapt to these changes include broad long-term pro-poor strategies designed to manage the persistent problem of overfishing and declining fish stocks. However, one immediate coping strategy is beginning to emerge, the more active use of reliable weather information. Based on 80 semi-structured interviews conducted in Senegal, Ghana, and Nigeria between 2021 and 2022, this study investigates claims that the use of weather information (WI) is helping West African artisanal fishers and those involved in secondary fishery activities to build more climate-resilient household income and food security. Unlike the long-term measures for mitigating the impact of climate change, results from the study show that by assessing the risk, their marine capture activities using weather information, fishers are immediately benefitting. Using the diffusion of the innovation theory to investigate the pattern of fishers’ adoption and usage of weather information, we found that Senegalese marine artisanal fishers can be classified as “Early Adopters” of this innovation. However, this is not the case with inland fishers who remain skeptical and will only use weather information if they can ascertain its reliability. West Africa’s inland fisheries sector is often neglected in climate change strategies: there is a lack of coordinated action to understand the weather information needs of these vulnerable fishers in order to coassess and codevelop bespoke weather products that offer benefits to them. However, West Africa’s fisheries, especially those inland, are too important to ignore if the United Nations Sustainable Development Goals (UNSDGs), including no poverty and zero hunger, are to be achieved. To help this sector fully benefit from the use of weather information, this study recommends detailed research into the weather information needs of these fishers and user-friendly ways to engage with the fishers to transmit the information.

Managing masculinities: dynamics of offshore fishing labour in Vietnam

Vietnam’s offshore fishing industry remains a space dominated by men, with fish work being tied to notions of what it means to be a man. This paper uses interviews data and participant observation to assess the ways in which masculinities shape and are shaped by labour relations in offshore fishing in Southern Vietnam. Findings show that labour relations are maintained through an emphasis on the abilities of men to do difficult physical work, behavioural expectations associated with masculine norms, and a homosocial bonding culture at sea, in addition to a bonding culture on land that involves drinking and women as entertainment. Multiple masculinities are identified with varying degrees of fluidity as informed especially by class and with dynamics differing at sea versus on land. In a context of fish stock decline and international pressure for strict fisheries reform, efforts to sustain an offshore fishing workforce rely, in part, on the reproduction of a particular local hierarchy of masculinities.

Species differences, but not habitat, influence catch rate hyperstability across a recreational fishery landscape

In commercial and recreational fisheries, catch rate is often assumed to be proportional to stock size and is used by managers and fishers as an indicator of fishery sustainability. If catch rate is proportional to stock size, it can signal a decline of stocks and managers can impose restrictive harvest policies or recreational anglers can move to a new system and allow the over-exploited system to rebound. A growing literature has documented catch rates remaining high even as fish stocks decline (i.e., hyperstability of catch rates) leading to delayed management intervention and overexploitation. Although recent evidence has indicated the presence of hyperstability of catch rates in recreational fisheries, whether hyperstability differs across species or system types remains unknown. To investigate whether catch rate hyperstability varies amongst species or systems, we first tested whether electrofishing catch per unit effort (efCPUE) was an appropriate proxy for true abundance. We then compared the relationship between angler catch rate and fish abundance for common freshwater sport fishes across gradients of habitat availability. We found significant differences in the strength of hyperstability amongst species. We did not identify a consistent influence of habitat on hyperstability of catch rates. Angler preferences and behavior may explain some of the variance in non-proportional catch rates. Future research investigating angler behavior, population size structure, and population dynamics in these systems may identify key interactions that create differences in vulnerability to population collapse.

New Insight Into the Reproductive Biology and Catch of Juveniles of the Lutjanus purpureus in a Portion of the Great Amazon Reef System Off the Northern Brazilian Coast

The Southern red snapper, Lutjanus purpureus, is a valuable economic resource, especially in international market. However, no recent data are available on the reproductive biology of this species in Brazilian waters, in particular, the stock found on the Amazon reef. The present study evaluated the population structure and reproductive biology of L. purpureus, and the volume of the catch of juveniles taken by the local commercial fisheries. A total of 923 specimens were analyzed, of which, 577 were female and 346 male (sex ratio: 0.6:1; p < 0.05). The analysis of the gonadosomatic index (GSI) and the distribution of maturation stages indicated that the males and females are able to reproduce throughout the year, however the reproductive peak occurs simultaneously with the increase in the water discharge of the Amazon River. The spawning females were registered in the study area, indicating that L. purpureus does not perform long distance reproductive migrations, different from the previously proposed. The Fork length at first sexual maturation (FL50) was estimated to be 35.2 cm in the males and 32.1 cm in the females. The high frequency of juveniles (< FL50) captured by the commercial snapper fleet using longlines (33.67% of the total catch) and traps (42.1%) indicates the poor selectivity of the fishing gear used by the snapper fleet, which may contribute to the accelerated depletion of the L. purpureus stock. Although the results of this study show a catch percentage of juveniles >50%, it is still a significant percentage of juveniles that are being caught due to little or no guidance and enforcement of fishing gear to ensure compliance with current legislation. Considering the data presented in this study and the current situation of declining fish stocks of L. purpureus, an assessment is recommended for the inclusion of the species in the IUCN Red List of Threatened Species, which is currently a species categorized as “vulnerable” in the Brazilian Red List.