Mitigating elasmobranch fin trade: A market analysis for made-to-measure interventions.

The unsustainable trade in elasmobranch products, particularly fins, contributes to the decline of elasmobranch populations worldwide. Designing and implementing context-appropriate solutions to mitigate unsustainable trade requires a thorough analysis of markets. Here we assess the market component of the elasmobranch fin trade in the Bay of Bengal, Bangladesh, using a framework designed to analyse wildlife markets. Using a mixed-method approach, we characterised the market to identify the components contributing to unsustainable practices. By-catch retention levels were high leading to the development of a solid market. Trade on fins was prevalent due to a high price, lack of awareness, actors' limited ability to adhere to regulations, and no strategies and incentives to limit fishing mortality. An imbalanced power and financial structure between actors were revealed, with some actors accessing unequal benefits from the market. Impediments for adopting conservation measures by low-access actors (e.g., fishers) with limited decision-making power or resources were evident. We also identified challenges to enforcement primarily due to limited reporting and issues identifying species and products. Fishers noted several socio-ecological, technical, and enforcement issues (e.g., policing instead of meaningful monitoring, punitive measures without facilitating compliance), that will require adequate time and resources to change practices. Lack of opportunities and information to adhere to regulations and increased enforcement has led to conflicts, non-compliance and unwillingness to report catches. The study has significantly strengthened the current understanding of Bangladesh's complex elasmobranch product market while highlighting critical knowledge gaps that must be addressed to inform and improve management decisions. Based on the findings, we recommend targeted actions to respond to the current market for mitigating elasmobranch product trade and moving towards establishing sustainable and ethical trade. Our work has both regional and global significance, given the role of the Bay of Bengal nations in the worldwide elasmobranch product market.

New records of elasmobranchs in the Bay of Bengal, Bangladesh: further taxonomic research is essential.

To evaluate the species diversity and strengthen the taxonomic identification of elasmobranchs in the Bay of Bengal, Bangladesh, a study was conducted in the southeast coastal region between January 2016 and March 2018. Using morphological and genetic identification techniques, this study presents 22 species from the region. Thirteen of these are new records. The new records consist of eight species from the family Dasyatidae, and one each from Mobulidae, Rhinobatidae, Narcinidae, Hemiscylliidae and Triakidae. Furthermore, four occurrences are first verified reports, and five are potential new records requiring further taxonomic investigation.

Evaluating artisanal fishing of globally threatened sharks and rays in the Bay of Bengal, Bangladesh.

Sharks and rays are at risk of extinction globally. This reflects low resilience to increasing fishing pressure, exacerbated by habitat loss, climate change, increasing value in a trade and inadequate information leading to limited conservation actions. Artisanal fisheries in the Bay of Bengal of Bangladesh contribute to the high levels of global fishing pressure on elasmobranchs. However, it is one of the most data-poor regions of the world, and the diversity, occurrence and conservation needs of elasmobranchs in this region have not been adequately assessed. This study evaluated elasmobranch diversity, species composition, catch and trade within the artisanal fisheries to address this critical knowledge gap. Findings show that elasmobranch diversity in Bangladesh has previously been underestimated. In this study, over 160000 individual elasmobranchs were recorded through landing site monitoring, comprising 88 species (30 sharks and 58 rays) within 20 families and 35 genera. Of these, 54 are globally threatened according to the IUCN Red List of Threatened Species, with ten species listed as Critically Endangered and 22 species listed as Endangered. Almost 98% juvenile catch (69-99% for different species) for large species sand a decline in numbers of large individuals were documented, indicating unsustainable fisheries. Several previously common species were rarely landed, indicating potential population declines. The catch pattern showed seasonality and, in some cases, gear specificity. Overall, Bangladesh was found to be a significant contributor to shark and ray catches and trade in the Bay of Bengal region. Effective monitoring was not observed at the landing sites or processing centres, despite 29 species of elasmobranchs being protected by law, many of which were frequently landed. On this basis, a series of recommendations were provided for improving the conservation status of the elasmobranchs in this region. These include the need for improved taxonomic research, enhanced monitoring of elasmobranch stocks, and the highest protection level for threatened taxa. Alongside political will, enhancing national capacity to manage and rebuild elasmobranch stocks, coordinated regional management measures are essential.

Riverine plastic pollution from fisheries: Insights from the Ganges River system.

Abandoned, lost or otherwise discarded fishing gear represents a substantial proportion of global marine plastic pollution and can cause significant environmental and socio-economic impacts. Yet little is known about its presence in, and implications for, freshwater ecosystems or its downstream contribution to plastic pollution in the ocean. This study documents fishing gear-related debris in one of the world's largest plastic pollution contributing river catchments, the Ganges. Riverbank surveys conducted along the length of the river, from the coast in Bangladesh to the Himalaya in India, show that derelict fishing gear density increases with proximity to the sea. Fishing nets were the main gear type by volume and all samples examined for polymer type were plastic. Illegal gear types and restricted net mesh sizes were also recorded. Socio-economic surveys of fisher communities explored the behavioural drivers of plastic waste input from one of the world's largest inland fisheries and revealed short gear lifespans and high turnover rates, lack of appropriate end-of-life gear disposal methods and ineffective fisheries regulations. A biodiversity threat assessment identified the air-breathing aquatic vertebrate species most at risk of entanglement in, and impacts from, derelict fishing gear; namely species of threatened freshwater turtle and otter, and the endangered Ganges river dolphin. This research demonstrates a need for targeted and practical interventions to limit the input of fisheries-related plastic pollution to this major river system and ultimately, the global ocean. The approach used in this study could be replicated to examine the inputs, socio-economic drivers and ecological impacts of this previously uncharacterised but important source of plastic pollution in other major rivers worldwide.

DNA analysis of elasmobranch products originating from Bangladesh reveals unregulated elasmobranch fishery and trade on species of global conservation concern.

Trade involving elasmobranch products in Bangladesh is a four-decade-long practice in large scale and there is little understanding of its impact on species composition, population, and subsequent conservation. Capacity for monitoring and identification is lacking in landing and shark processing centres. A rapid survey and collection of tissue samples were performed in three landings and nine shark processing centres between 2016 and 2017 in the south-eastern coastal region of Bangladesh. Sequencing for a 707-bp fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene was used to assess the taxonomic status and species composition from 71 elasmobranch tissue samples collected from the shark processing centre only. Good quality COI sequences were obtained for 34 specimens representing 21 species-the majority of which are threatened with extinction. A total of ten species of sharks (Carcharhinus brevipinna, C. amboinensis, C. leucas, C. sorrah, C. amblyrhynchoides, Chiloscyllium burmensis, Galeocerdo cuvier, Rhincodon typus, Scoliodon laticaudus, and Sphyrna lewini), eleven species of rays (Aetomylaeus maculatus, Gymnura poecilura, Mobula mobular, M. kuhlii, Neotrygon indica, Pateobatis uarnacoides, Rhinoptera javanica, and R. jayakari), including three species of guitarfish (Glaucostegus granulatus, G. obtusus, and G. typus), were identified. Four species (14.7% of samples) were found to be listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in Appendix II. Sixteen species (59% of the specimens) were threatened with extinction according to IUCN Red List, whereas 41% were data deficient or not assessed. The results have important implications for the management of regional fisheries and the conservation of elasmobranchs as they 1) represent a preliminary understanding of elasmobranch diversity in trade; 2) depict a lack of awareness and monitoring; and 3) demonstrate a need for urgent monitoring and regulation of elasmobranch trade in Bangladesh.