{"title":"An ecological view in time and space: The disappearing sawfishes in the Bay of Bengal, Bangladesh","authors":"Alifa Bintha Haque , Subrata Sarker , Shashowti Chowdhury Riya , Nidhi G. D’Costa , Eurida Liyana , ANM Samiul Huda","doi":"10.1016/j.jnc.2025.127059","DOIUrl":null,"url":null,"abstract":"<div><div>Sawfish are Critically Endangered globally, necessitating spatial protection and fisheries management in critical habitats for their preservation. Understanding of such habitats remains limited in the Bay of Bengal, despite the confirmed presence of at least three sawfish species. However, in the past, the species most frequently captured from Bangladesh was the Largetooth Sawfish (<em>Pristis pristis</em>). In this study, using a multidisciplinary approach of ecological modelling of suitable habitats and ground-truthing using fishers' knowledge, habitats for sawfish were identified in Bangladesh’s coastal waters. This was achieved by applying an ethnoecological and georeferenced habitat database to determine suitable habitat for sawfish (mostly Largetooth Sawfish). Landsat imagery and thematic layers were analyzed with ENVI and GIS and developed a series of GIS models to identify and rank suitable grounds. The model outputs were verified with fishers’ local ecological knowledge with an accuracy level of 93%. According to the fishers, catches (from 2019 to 2021) were primarily from the Sundarbans mangrove region, while 60% of fishers reported not observing a sawfish for over two decades in the wild, roughly since the early 2000 s. Most fishers highlighted shallow coastal zones and mangrove-associated rivers as critical habitats for juvenile and adult sawfish. Ecological modeling using a Generalized Additive Model (GAM) revealed that water depth and salinity were the primary drivers of habitat suitability, explaining 19 % and 16 % of the variance, respectively. We found the southwest region, particularly the Sundarbans, as the most potential critical habitat for sawfishes in Bangladesh. We recommend immediate spatial conservation measures and bycatch mitigation amongst others, for the long-term population recovery of sawfish in Bangladesh.</div></div>","PeriodicalId":54898,"journal":{"name":"Journal for Nature Conservation","volume":"89 ","pages":"Article 127059"},"PeriodicalIF":2.5000,"publicationDate":"2025-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal for Nature Conservation","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1617138125002365","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIODIVERSITY CONSERVATION","Score":null,"Total":0}
引用次数: 0
Abstract
Sawfish are Critically Endangered globally, necessitating spatial protection and fisheries management in critical habitats for their preservation. Understanding of such habitats remains limited in the Bay of Bengal, despite the confirmed presence of at least three sawfish species. However, in the past, the species most frequently captured from Bangladesh was the Largetooth Sawfish (Pristis pristis). In this study, using a multidisciplinary approach of ecological modelling of suitable habitats and ground-truthing using fishers' knowledge, habitats for sawfish were identified in Bangladesh’s coastal waters. This was achieved by applying an ethnoecological and georeferenced habitat database to determine suitable habitat for sawfish (mostly Largetooth Sawfish). Landsat imagery and thematic layers were analyzed with ENVI and GIS and developed a series of GIS models to identify and rank suitable grounds. The model outputs were verified with fishers’ local ecological knowledge with an accuracy level of 93%. According to the fishers, catches (from 2019 to 2021) were primarily from the Sundarbans mangrove region, while 60% of fishers reported not observing a sawfish for over two decades in the wild, roughly since the early 2000 s. Most fishers highlighted shallow coastal zones and mangrove-associated rivers as critical habitats for juvenile and adult sawfish. Ecological modeling using a Generalized Additive Model (GAM) revealed that water depth and salinity were the primary drivers of habitat suitability, explaining 19 % and 16 % of the variance, respectively. We found the southwest region, particularly the Sundarbans, as the most potential critical habitat for sawfishes in Bangladesh. We recommend immediate spatial conservation measures and bycatch mitigation amongst others, for the long-term population recovery of sawfish in Bangladesh.
期刊介绍:
The Journal for Nature Conservation addresses concepts, methods and techniques for nature conservation. This international and interdisciplinary journal encourages collaboration between scientists and practitioners, including the integration of biodiversity issues with social and economic concepts. Therefore, conceptual, technical and methodological papers, as well as reviews, research papers, and short communications are welcomed from a wide range of disciplines, including theoretical ecology, landscape ecology, restoration ecology, ecological modelling, and others, provided that there is a clear connection and immediate relevance to nature conservation.
Manuscripts without any immediate conservation context, such as inventories, distribution modelling, genetic studies, animal behaviour, plant physiology, will not be considered for this journal; though such data may be useful for conservationists and managers in the future, this is outside of the current scope of the journal.