Mia J. Groeneveld, Juliana D. Klein, Rhett H. Bennett, Abdalla S. Abdulla, Mark E. Bond, David A. Ebert, Stela M. Fernando, Katie S. Gledhill, Sebastien Jaquemet, Jeremy J. Kiszka, Angus H. H. Macdonald, Bruce Q. Mann, John Nevill, Aidan S. Price, Jordan Rumbelow, Jorge J. Sitoe, Michaela van Staden, Barbara E. Wueringer, Aletta E. Bester-van der Merwe
ABSTRACT: Wedgefishes (Rhinidae) are threatened by unsustainable fishing globally, and especially in the Southwest Indian Ocean (SWIO), due to their high-value fins in the shark trade. The whitespotted wedgefish Rhynchobatus djiddensis and the bottlenose wedgefish R. australiae are both classified as Critically Endangered on the IUCN Red List of Threatened Species, yet a lack of species-specific knowledge and taxonomic uncertainty still exists within this genus. Genetic approaches aid in taxonomic classification and identifying distinct populations for targeted conservation. Morphological specimen identification of samples (n = 189) collected across the SWIO was confirmed based on the cytochrome oxidase c subunit I (COI) and/or nicotinamide adenine dehydrogenase subunit 2 (ND2) gene regions. The genetic diversity and population structure within and between species and sampling locations were investigated using a dual marker approach: (1) 2 concatenated mitochondrial gene regions, namely COI and the control region (n = 117), and (2) 9 nuclear microsatellite markers (n = 146). The overall genetic diversity was moderate, with an indication that different evolutionary forces are at play on a mitochondrial versus nuclear level. The 2 species were delineated based on both marker types, and for R. djiddensis, the sampling locations of South Africa and Mozambique were genetically homogeneous. For R. australiae, significant differentiation was found between sampling locations, with Madagascar and Tanzania being genetically the most similar. This information provides critical insights into the distribution range and population structure of the whitespotted wedgefish species complex that can support the sustainable management of wedgefishes.
摘要：楔鱼（Rhinidae）因其鱼翅在鲨鱼贸易中的高价值而受到全球不可持续捕捞的威胁，尤其是在西南印度洋（SWIO）。白斑楔鱼（Rhynchobatus djiddensis）和瓶鼻楔鱼（R. australiae）在世界自然保护联盟濒危物种红色名录中均被列为极度濒危物种，但在该属中仍然存在物种特异性知识缺乏和分类不确定性的问题。遗传学方法有助于分类和确定不同的种群，以便进行有针对性的保护。根据细胞色素氧化酶 c 亚基 I（COI）和/或烟酰胺腺嘌呤脱氢酶亚基 2（ND2）基因区域，对在西南印度洋各地采集的样本（n = 189）进行了形态标本鉴定。采用双重标记法研究了种内和种间以及采样地点之间的遗传多样性和种群结构：（1）2 个线粒体基因连接区，即 COI 和控制区（n = 117）；（2）9 个核微卫星标记（n = 146）。总体遗传多样性适中，表明线粒体与核水平上的进化力量不同。对于 R. djiddensis 而言，南非和莫桑比克的取样地点在遗传上是同质的。对于 R. australiae，取样地点之间存在显著差异，其中马达加斯加和坦桑尼亚的基因最为相似。这些信息为了解白斑楔鱼物种群的分布范围和种群结构提供了重要信息，有助于楔鱼的可持续管理。
{"title":"Population genetic structure of bottlenose and whitespotted wedgefishes from the Southwest Indian Ocean using a dual marker approach","authors":"Mia J. Groeneveld, Juliana D. Klein, Rhett H. Bennett, Abdalla S. Abdulla, Mark E. Bond, David A. Ebert, Stela M. Fernando, Katie S. Gledhill, Sebastien Jaquemet, Jeremy J. Kiszka, Angus H. H. Macdonald, Bruce Q. Mann, John Nevill, Aidan S. Price, Jordan Rumbelow, Jorge J. Sitoe, Michaela van Staden, Barbara E. Wueringer, Aletta E. Bester-van der Merwe","doi":"10.3354/esr01311","DOIUrl":"https://doi.org/10.3354/esr01311","url":null,"abstract":"ABSTRACT: Wedgefishes (Rhinidae) are threatened by unsustainable fishing globally, and especially in the Southwest Indian Ocean (SWIO), due to their high-value fins in the shark trade. The whitespotted wedgefish <i>Rhynchobatus djiddensis</i> and the bottlenose wedgefish <i>R. australiae</i> are both classified as Critically Endangered on the IUCN Red List of Threatened Species, yet a lack of species-specific knowledge and taxonomic uncertainty still exists within this genus. Genetic approaches aid in taxonomic classification and identifying distinct populations for targeted conservation. Morphological specimen identification of samples (n = 189) collected across the SWIO was confirmed based on the cytochrome oxidase c subunit I (<i>COI</i>) and/or nicotinamide adenine dehydrogenase subunit 2 (<i>ND2</i>) gene regions. The genetic diversity and population structure within and between species and sampling locations were investigated using a dual marker approach: (1) 2 concatenated mitochondrial gene regions, namely <i>COI</i> and the control region (n = 117), and (2) 9 nuclear microsatellite markers (n = 146). The overall genetic diversity was moderate, with an indication that different evolutionary forces are at play on a mitochondrial versus nuclear level. The 2 species were delineated based on both marker types, and for <i>R. djiddensis</i>, the sampling locations of South Africa and Mozambique were genetically homogeneous. For <i>R. australiae</i>, significant differentiation was found between sampling locations, with Madagascar and Tanzania being genetically the most similar. This information provides critical insights into the distribution range and population structure of the whitespotted wedgefish species complex that can support the sustainable management of wedgefishes.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrew C. Jesper, Scott A. Eckert, Scott R. Ballard, John A. Crawford, Michael J. Dreslik
ABSTRACT: The dependency on hibernacula for extended periods presents terrestrial reptiles with the challenge of locating thermally adequate hibernacula each winter. Defining the habitat characteristics of hibernacula is crucial for understanding the overwintering requirements and distributions of hibernacula-dependent reptiles, alongside identifying habitats which warrant special conservation concern. Our objectives were to identify the overwintering habitat characteristics of the imperiled timber rattlesnake Crotalus horridus in Illinois, USA, and to determine the distribution of likely hibernacula habitats throughout the state. Due to the initial sparsity of hibernacula records in Illinois, we adopted an iterative habitat suitability modeling process consisting of 3 distinct rounds of Maxent construction and revision. Each round was informed with updated information from model-guided surveys or by building rapport with in-state naturalists and researchers who knew of additional hibernacula locations. We created our final model using 36 hibernacula and identified slope angle (indicative of rock outcrops and shallow soils), topographical position index, forest patch area, and aspect (decomposed into 2 linearized variables: southness and eastness) as important drivers of C. horridus hibernacula habitat in Illinois. Together, the 5 variables and site surveys suggest the suitable overwintering habitat for C. horridus in Illinois is located on south- to southwest-facing outcrops on upper slopes and ridges of larger forest patches. Such habitat is distributed primarily in southern Illinois and throughout the Mississippi River and Illinois River border counties. Our study adds to the current understanding of the species’ overwintering requirements and provides a foundation for future ecological studies, management, and survey efforts throughout Illinois.
{"title":"Distribution and drivers of critical hibernacula for the timber rattlesnake Crotalus horridus in Illinois, USA","authors":"Andrew C. Jesper, Scott A. Eckert, Scott R. Ballard, John A. Crawford, Michael J. Dreslik","doi":"10.3354/esr01312","DOIUrl":"https://doi.org/10.3354/esr01312","url":null,"abstract":"ABSTRACT: The dependency on hibernacula for extended periods presents terrestrial reptiles with the challenge of locating thermally adequate hibernacula each winter. Defining the habitat characteristics of hibernacula is crucial for understanding the overwintering requirements and distributions of hibernacula-dependent reptiles, alongside identifying habitats which warrant special conservation concern. Our objectives were to identify the overwintering habitat characteristics of the imperiled timber rattlesnake <i>Crotalus horridus</i> in Illinois, USA, and to determine the distribution of likely hibernacula habitats throughout the state. Due to the initial sparsity of hibernacula records in Illinois, we adopted an iterative habitat suitability modeling process consisting of 3 distinct rounds of Maxent construction and revision. Each round was informed with updated information from model-guided surveys or by building rapport with in-state naturalists and researchers who knew of additional hibernacula locations. We created our final model using 36 hibernacula and identified slope angle (indicative of rock outcrops and shallow soils), topographical position index, forest patch area, and aspect (decomposed into 2 linearized variables: southness and eastness) as important drivers of <i>C. horridus</i> hibernacula habitat in Illinois. Together, the 5 variables and site surveys suggest the suitable overwintering habitat for <i>C. horridus</i> in Illinois is located on south- to southwest-facing outcrops on upper slopes and ridges of larger forest patches. Such habitat is distributed primarily in southern Illinois and throughout the Mississippi River and Illinois River border counties. Our study adds to the current understanding of the species’ overwintering requirements and provides a foundation for future ecological studies, management, and survey efforts throughout Illinois.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316391","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: Climate change can result in alterations to avian behavior, particularly in migratory species. We assessed long-term changes in the endangered whooping crane Grus americana migration phenology in response to temperature, precipitation, and other determinants of migratory behavior. We modeled timing of abundance peaks on the Texas wintering grounds as a function of date and year. During spring and fall migration in central Saskatchewan, we modeled timing of earliest and latest observations, and period of occurrence between them, as a function of year, weather, and wheat production. During winters 1950-2010, the peak abundance period (≥90% of population) shortened. In winter 1950-1951, the peak was 28 November-12 March, but by winter 2010-2011, it was 18 December-20 February. We predict it will shrink to 2 January-6 February by winter 2035-2036. During fall migration 1972-2021, the period cranes occurred in central Saskatchewan lengthened by 20.3 d. In 1971, cranes arrived by 16 September and departed by 17 October, but by 2021 they arrived 12 d earlier (4 September) and departed 17 d later (3 November). We predict a lengthened period of occurrence of 63.8 d by fall 2035 (arrival by 1 September, departure by 8 November). During spring migration 1979-2021, there were no trends in migration phenology (mean period of occurrence was 32 d). Alterations in migration phenology may require modified conservation approaches and consideration of new conservation opportunities. For example, these changes may reduce time cranes spend on the wintering grounds, requiring greater investment in stopover areas.
{"title":"Long-term migratory alterations to whooping crane arrival and departure on the wintering and staging grounds","authors":"Matthew J. Butler, Mark T. Bidwell","doi":"10.3354/esr01315","DOIUrl":"https://doi.org/10.3354/esr01315","url":null,"abstract":"ABSTRACT: Climate change can result in alterations to avian behavior, particularly in migratory species. We assessed long-term changes in the endangered whooping crane <i>Grus americana</i> migration phenology in response to temperature, precipitation, and other determinants of migratory behavior. We modeled timing of abundance peaks on the Texas wintering grounds as a function of date and year. During spring and fall migration in central Saskatchewan, we modeled timing of earliest and latest observations, and period of occurrence between them, as a function of year, weather, and wheat production. During winters 1950-2010, the peak abundance period (≥90% of population) shortened. In winter 1950-1951, the peak was 28 November-12 March, but by winter 2010-2011, it was 18 December-20 February. We predict it will shrink to 2 January-6 February by winter 2035-2036. During fall migration 1972-2021, the period cranes occurred in central Saskatchewan lengthened by 20.3 d. In 1971, cranes arrived by 16 September and departed by 17 October, but by 2021 they arrived 12 d earlier (4 September) and departed 17 d later (3 November). We predict a lengthened period of occurrence of 63.8 d by fall 2035 (arrival by 1 September, departure by 8 November). During spring migration 1979-2021, there were no trends in migration phenology (mean period of occurrence was 32 d). Alterations in migration phenology may require modified conservation approaches and consideration of new conservation opportunities. For example, these changes may reduce time cranes spend on the wintering grounds, requiring greater investment in stopover areas.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jolene Hanna, Jen Hazeres, Rob Wilson, Stephanie Snyder Koch
ABSTRACT: Wedgefishes, family Rhinidae, are collectively identified as one of the most threatened groups of chondrichthyan fishes globally by the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species. Within the family Rhinidae, bowmouth guitarfish Rhina ancylostoma have been designated by the IUCN as Critically Endangered since 2018. Bowmouth guitarfish were first introduced to the Association of Zoos and Aquariums (AZA) in 2005 when the Newport Aquarium, Newport, KY, USA, acquired a single female. In 2007, a male bowmouth guitarfish was added into the collection with the goal of establishing an institutional breeding program and to generate foundational knowledge for future breeding programs. This study presents an ethogram of mating behaviors exhibited by a mixed sex group of bowmouth guitarfish using behavioral observations from December 2017 through August 2022. The observed interactions between male and female bowmouth guitarfish led to the identification of 5 male reproductive behaviors: hovering, chasing, wrapping up, flipping/rolling, and copulation. These 5 behaviors were directly linked with successful reproduction, e.g. active breeding and live parturition, in the imperiled species R. ancylostoma. The breeding behavioral knowledge presented within this study provides the first step to a viable breeding program, a critical tool for conserving wild populations.
{"title":"Observations of reproductive behaviors in the Critically Endangered bowmouth guitarfish Rhina ancylostoma","authors":"Jolene Hanna, Jen Hazeres, Rob Wilson, Stephanie Snyder Koch","doi":"10.3354/esr01313","DOIUrl":"https://doi.org/10.3354/esr01313","url":null,"abstract":"ABSTRACT: Wedgefishes, family Rhinidae, are collectively identified as one of the most threatened groups of chondrichthyan fishes globally by the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species. Within the family Rhinidae, bowmouth guitarfish <i>Rhina ancylostoma</i> have been designated by the IUCN as Critically Endangered since 2018. Bowmouth guitarfish were first introduced to the Association of Zoos and Aquariums (AZA) in 2005 when the Newport Aquarium, Newport, KY, USA, acquired a single female. In 2007, a male bowmouth guitarfish was added into the collection with the goal of establishing an institutional breeding program and to generate foundational knowledge for future breeding programs. This study presents an ethogram of mating behaviors exhibited by a mixed sex group of bowmouth guitarfish using behavioral observations from December 2017 through August 2022. The observed interactions between male and female bowmouth guitarfish led to the identification of 5 male reproductive behaviors: hovering, chasing, wrapping up, flipping/rolling, and copulation. These 5 behaviors were directly linked with successful reproduction, e.g. active breeding and live parturition, in the imperiled species <i>R. ancylostoma</i>. The breeding behavioral knowledge presented within this study provides the first step to a viable breeding program, a critical tool for conserving wild populations.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: The Hawaiian monk seal Neomonachusschauinslandi, one of the world’s most endangered pinnipeds, has faced decades of declines and has been the focus of intensive conservation efforts. A myriad of conservation threats has led to range-wide population declines, but population trends among islands can vary widely in response to heterogeneous threats. Populations in the Northwestern Hawaiian Islands have been declining, whereas Main Hawaiian Islands numbers are expanding. Molecular data can provide information to disentangle population structure and dynamics; however, previous studies have yielded insufficient resolution in such a genetically depauperate species. Advances in genomic technology and affordability offer a novel opportunity to revisit questions about Hawaiian monk seal trends with high-resolution markers that provide better discrimination ability in low-diversity species. Here, we investigated region- and island-level population structuring and connectivity. We used BestRAD sequencing on 169 seals from 14 islands that span the archipelago to estimate genetic diversity, genetic differentiation, population structure, and migration rates. We did not find robust evidence for island-level population structure. For the first time, our data set provided resolution to differentiate regional populations with low but significant genetic differentiation. Further, DAPC illustrated population structure with evidence for connectivity, which mirrored our migration rate estimates. Future conservation decisions will need to consider the balance of maintaining connectivity between regions while not homogenizing and losing valuable, yet rare, regional unique variation.
{"title":"Genomic analysis of population history for Hawaiian monk seals","authors":"Samantha Hauser, Stacie Robinson, Emily Latch","doi":"10.3354/esr01308","DOIUrl":"https://doi.org/10.3354/esr01308","url":null,"abstract":"ABSTRACT: The Hawaiian monk seal <i>Neomonachus</i> <i>schauinslandi</i>, one of the world’s most endangered pinnipeds, has faced decades of declines and has been the focus of intensive conservation efforts. A myriad of conservation threats has led to range-wide population declines, but population trends among islands can vary widely in response to heterogeneous threats. Populations in the Northwestern Hawaiian Islands have been declining, whereas Main Hawaiian Islands numbers are expanding. Molecular data can provide information to disentangle population structure and dynamics; however, previous studies have yielded insufficient resolution in such a genetically depauperate species. Advances in genomic technology and affordability offer a novel opportunity to revisit questions about Hawaiian monk seal trends with high-resolution markers that provide better discrimination ability in low-diversity species. Here, we investigated region- and island-level population structuring and connectivity. We used BestRAD sequencing on 169 seals from 14 islands that span the archipelago to estimate genetic diversity, genetic differentiation, population structure, and migration rates. We did not find robust evidence for island-level population structure. For the first time, our data set provided resolution to differentiate regional populations with low but significant genetic differentiation. Further, DAPC illustrated population structure with evidence for connectivity, which mirrored our migration rate estimates. Future conservation decisions will need to consider the balance of maintaining connectivity between regions while not homogenizing and losing valuable, yet rare, regional unique variation.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shane P. Griffiths, Bryan P. Wallace, Verónica Cáceres, Luz Helena Rodríguez, Jon Lopez, Marino Abrego, Joanna Alfaro-Shigueto, Sandra Andraka, María José Brito, Leslie Camila Bustos, Ilia Cari, José Miguel Carvajal, Ljubitza Clavijo, Luis Cocas, Nelly de Paz, Marco Herrera, Ann Marie Lauritsen, Jeffrey C. Mangel, Miguel Pérez-Huaripata, Rotney Piedra, Javier Antonio Quiñones Dávila, Liliana Rendón, Juan M. Rguez-Baron, Heriberto Santana, Brian Stacy, Jenifer Suárez, Yonat Swimmer, Callie Veelenturf, Rodrigo Vega, Patricia Zárate
ABSTRACT: Industrial tuna and artisanal fisheries targeting multiple species in the eastern Pacific Ocean (EPO) interact with the Critically Endangered East Pacific (EP) leatherback turtle Dermochelys coriacea. In 2021, a revised Inter-American Tropical Tuna Commission (IATTC) resolution on sea turtles aimed to reduce sea turtle bycatch in EPO industrial tuna fisheries and ensure their safe handling and release. A new ecological risk assessment approach—Ecological Assessment for the Sustainable Impacts of Fisheries (EASI-Fish)—was used to assess vulnerability status and to better understand the potential efficacy of 70 scenarios that compared simulated conservation and management measures (CMMs) for EPO industrial (purse-seine and longline) and artisanal (longline and gillnet) fisheries to the status quo in 2019. In 2019, a fishing mortality proxy (F̃2019) and the breeding stock biomass per recruit (BSR2019) exceeded precautionary biological reference points (F80% and BSR80%), classifying the stock as ‘most vulnerable’. Industrial and artisanal longline fisheries had the highest impacts because they had the highest areal overlap with the modelled EP leatherback distribution. Of the 70 CMM scenarios, 42 resulted in significant improvements in vulnerability status (i.e. to ‘least vulnerable’). The use of large circle hooks, finfish bait, and best handling and release practices each decreased vulnerability; however, the most effective scenarios involved using these 3 measures in concert. The benefits predicted from EASI-Fish for CMM scenarios assume full compliance and attaining the modelled levels of efficacy, our modelling provides stakeholders with evidence-based recommendations to address key threats to EP leatherback turtles to improve their conservation status by reducing fishing impacts.
{"title":"Vulnerability of the Critically Endangered leatherback turtle to fisheries bycatch in the eastern Pacific Ocean. II. Assessment of mitigation measures","authors":"Shane P. Griffiths, Bryan P. Wallace, Verónica Cáceres, Luz Helena Rodríguez, Jon Lopez, Marino Abrego, Joanna Alfaro-Shigueto, Sandra Andraka, María José Brito, Leslie Camila Bustos, Ilia Cari, José Miguel Carvajal, Ljubitza Clavijo, Luis Cocas, Nelly de Paz, Marco Herrera, Ann Marie Lauritsen, Jeffrey C. Mangel, Miguel Pérez-Huaripata, Rotney Piedra, Javier Antonio Quiñones Dávila, Liliana Rendón, Juan M. Rguez-Baron, Heriberto Santana, Brian Stacy, Jenifer Suárez, Yonat Swimmer, Callie Veelenturf, Rodrigo Vega, Patricia Zárate","doi":"10.3354/esr01305","DOIUrl":"https://doi.org/10.3354/esr01305","url":null,"abstract":"ABSTRACT: Industrial tuna and artisanal fisheries targeting multiple species in the eastern Pacific Ocean (EPO) interact with the Critically Endangered East Pacific (EP) leatherback turtle <i>Dermochelys coriacea</i>. In 2021, a revised Inter-American Tropical Tuna Commission (IATTC) resolution on sea turtles aimed to reduce sea turtle bycatch in EPO industrial tuna fisheries and ensure their safe handling and release. A new ecological risk assessment approach—Ecological Assessment for the Sustainable Impacts of Fisheries (EASI-Fish)—was used to assess vulnerability status and to better understand the potential efficacy of 70 scenarios that compared simulated conservation and management measures (CMMs) for EPO industrial (purse-seine and longline) and artisanal (longline and gillnet) fisheries to the status quo in 2019. In 2019, a fishing mortality proxy (<i>F̃</i><sub>2019</sub>) and the breeding stock biomass per recruit (BSR<sub>2019</sub>) exceeded precautionary biological reference points (<i>F</i><sub>80%</sub> and BSR<sub>80%</sub>), classifying the stock as ‘most vulnerable’. Industrial and artisanal longline fisheries had the highest impacts because they had the highest areal overlap with the modelled EP leatherback distribution. Of the 70 CMM scenarios, 42 resulted in significant improvements in vulnerability status (i.e. to ‘least vulnerable’). The use of large circle hooks, finfish bait, and best handling and release practices each decreased vulnerability; however, the most effective scenarios involved using these 3 measures in concert. The benefits predicted from EASI-Fish for CMM scenarios assume full compliance and attaining the modelled levels of efficacy, our modelling provides stakeholders with evidence-based recommendations to address key threats to EP leatherback turtles to improve their conservation status by reducing fishing impacts.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: A thorough understanding of population demographics is important in planning and evaluating conservation actions. At the same time, it is also essential that conservation management strives to minimize uncertainty in decision making in order to avoid management errors, which in the case of endangered species might affect their persistence. Mediterranean monk seals are endangered and have been notoriously difficult to count, especially in the eastern Mediterranean Sea, where abundance estimates have relied mainly on expert judgement. To address this problem, a new approach to estimating the species’ demographics using ‘pup multipliers’ is introduced. Adopting a conservative and a more optimistic approach and following a review of the available species- and taxa-specific data, the following multipliers were proposed: 2.5-3.5 for estimating the number of mature individuals, and 4.5-6.0 for estimating the total number of individuals. These multipliers were then used to calculate, in a formal way, the population demographics of the Mediterranean monk seal in the eastern Mediterranean Sea and globally. In their current form, the pup multipliers proposed present a number of strengths, but also several caveats, limitations and/or points of concern and should therefore not be considered a panacea in the conservation of the species, but merely the starting point of efforts for further development. These efforts should ultimately aim at developing a population-specific pup multiplier for the Mediterranean monk seal that is based on a common monitoring approach between various countries and includes the collection of newborn pup count data from across the species’ range in the eastern Mediterranean Sea.
{"title":"Using ‘pup multipliers’ to estimate demographic parameters of Mediterranean monk seals in the eastern Mediterranean Sea","authors":"Alexandros A. Karamanlidis","doi":"10.3354/esr01301","DOIUrl":"https://doi.org/10.3354/esr01301","url":null,"abstract":"ABSTRACT: A thorough understanding of population demographics is important in planning and evaluating conservation actions. At the same time, it is also essential that conservation management strives to minimize uncertainty in decision making in order to avoid management errors, which in the case of endangered species might affect their persistence. Mediterranean monk seals are endangered and have been notoriously difficult to count, especially in the eastern Mediterranean Sea, where abundance estimates have relied mainly on expert judgement. To address this problem, a new approach to estimating the species’ demographics using ‘pup multipliers’ is introduced. Adopting a conservative and a more optimistic approach and following a review of the available species- and taxa-specific data, the following multipliers were proposed: 2.5-3.5 for estimating the number of mature individuals, and 4.5-6.0 for estimating the total number of individuals. These multipliers were then used to calculate, in a formal way, the population demographics of the Mediterranean monk seal in the eastern Mediterranean Sea and globally. In their current form, the pup multipliers proposed present a number of strengths, but also several caveats, limitations and/or points of concern and should therefore not be considered a panacea in the conservation of the species, but merely the starting point of efforts for further development. These efforts should ultimately aim at developing a population-specific pup multiplier for the Mediterranean monk seal that is based on a common monitoring approach between various countries and includes the collection of newborn pup count data from across the species’ range in the eastern Mediterranean Sea.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT: The Mediterranean monk seal Monachusmonachus is one of the most endangered marine mammals on Earth. The species has made a notable recovery during the past 10 yr and is now considered Vulnerable by the International Union for the Conservation of Nature. Its global population comprises 3 subpopulations: 2 in the northeastern Atlantic Ocean and one in the eastern Mediterranean Sea. Global estimated abundance is 815-997 individuals, including 443-599 mature individuals; annual pup production averages 170.5. Over the past decade, increased research efforts have shed new light on various aspects of the species’ biology and life history, including habitat and habitat use, vital rates, communication and genetics. The main threats to the species are (1) terrestrial and marine habitat loss and degradation that has or is resulting in the occupation of unsuitable habitat and limited prey availability, (2) negative interactions with fisheries that result in accidental entanglement or deliberate killings in response to damages to catches and/or fishing gear, (3) unpredictable threats, including cave collapses and mass mortality events and (4) pollution. Priority conservation actions for the species include (1) strengthening the legal framework for the protection of the terrestrial and marine habitat of the species, (2) effective protection of the species and its terrestrial and marine habitat, (3) scientific population and habitat monitoring, (4) rescue and rehabilitation of injured, orphaned and sick pups to increase neonatal survival rates, (5) public awareness and education, (6) monitoring and mitigating negative seal-fishery interactions and (7) expansion of the species’ current geographic range in the Atlantic Ocean.
{"title":"Current status, biology, threats and conservation priorities of the vulnerable Mediterranean monk seal","authors":"Alexandros A. Karamanlidis","doi":"10.3354/esr01304","DOIUrl":"https://doi.org/10.3354/esr01304","url":null,"abstract":"ABSTRACT: The Mediterranean monk seal <i>Monachus</i> <i>monachus</i> is one of the most endangered marine mammals on Earth. The species has made a notable recovery during the past 10 yr and is now considered Vulnerable by the International Union for the Conservation of Nature. Its global population comprises 3 subpopulations: 2 in the northeastern Atlantic Ocean and one in the eastern Mediterranean Sea. Global estimated abundance is 815-997 individuals, including 443-599 mature individuals; annual pup production averages 170.5. Over the past decade, increased research efforts have shed new light on various aspects of the species’ biology and life history, including habitat and habitat use, vital rates, communication and genetics. The main threats to the species are (1) terrestrial and marine habitat loss and degradation that has or is resulting in the occupation of unsuitable habitat and limited prey availability, (2) negative interactions with fisheries that result in accidental entanglement or deliberate killings in response to damages to catches and/or fishing gear, (3) unpredictable threats, including cave collapses and mass mortality events and (4) pollution. Priority conservation actions for the species include (1) strengthening the legal framework for the protection of the terrestrial and marine habitat of the species, (2) effective protection of the species and its terrestrial and marine habitat, (3) scientific population and habitat monitoring, (4) rescue and rehabilitation of injured, orphaned and sick pups to increase neonatal survival rates, (5) public awareness and education, (6) monitoring and mitigating negative seal-fishery interactions and (7) expansion of the species’ current geographic range in the Atlantic Ocean.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140124959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Manon Nivière, Mayeul Dalleau, Jérôme Bourjea, Claire Jean, Stéphane Ciccione, Jeanne A. Mortimer, Vanessa Didon, David Rowat, Gérard Rocamora, Ravaka Ranaivoson, Jamal Mahafina, Lalatiana Odile Randriamiharisoa, Eliott Barichasse, Olivier Bousquet, Anne Barat, Antoine Laforge, Katia Ballorain
ABSTRACT: Implementing effective conservation measures to manage migratory populations is challenging, especially in a relatively inaccessible dynamic environment such as the ocean. With limited financial and human resources, efforts must be intelligently prioritized to achieve conservation success and reduce uncertainties of conservation efforts. The southwest Indian Ocean (SWIO) hosts some of the world’s most important breeding grounds for the Critically Endangered hawksbill turtle Eretmochelysimbricata. However, knowledge gaps remain about the movement patterns of this species. Between 2007 and 2022, we deployed 17 satellite tags onto hawksbill turtles from scattered locations in the SWIO: 16 nesting females—Granitic Islands, Seychelles (n = 9); north Madagascar (n = 5); Moheli, Comoros (n = 1); Juan de Nova, Terres australes et antarctiques françaises (n = 1)—and 1 female bycaught in fisheries (east Madagascar). We found strong variability in migratory movements amongst individuals, particularly in terms of distance and movement persistence. Detailed analysis of movement persistence reveals that these individuals behave differently in neritic and oceanic habitats, with a lower movement persistence in neritic habitats. We identified a total of 12 foraging areas scattered throughout the SWIO, both in coastal and open-sea neritic habitats. These results reinforce the need to consider the importance of neritic habitats, for both migration and foraging, in conservation policies. The quantification of the degree of migratory variability is particularly important to developing conservation plans and strategies at both the national and international level, including the delineation of regional management units (RMUs) in the Indian Ocean.
{"title":"Intra-species variability in migratory movement of hawksbill turtles in the southwest Indian Ocean","authors":"Manon Nivière, Mayeul Dalleau, Jérôme Bourjea, Claire Jean, Stéphane Ciccione, Jeanne A. Mortimer, Vanessa Didon, David Rowat, Gérard Rocamora, Ravaka Ranaivoson, Jamal Mahafina, Lalatiana Odile Randriamiharisoa, Eliott Barichasse, Olivier Bousquet, Anne Barat, Antoine Laforge, Katia Ballorain","doi":"10.3354/esr01309","DOIUrl":"https://doi.org/10.3354/esr01309","url":null,"abstract":"ABSTRACT: Implementing effective conservation measures to manage migratory populations is challenging, especially in a relatively inaccessible dynamic environment such as the ocean. With limited financial and human resources, efforts must be intelligently prioritized to achieve conservation success and reduce uncertainties of conservation efforts. The southwest Indian Ocean (SWIO) hosts some of the world’s most important breeding grounds for the Critically Endangered hawksbill turtle <i>Eretmochelys</i> <i>imbricata</i>. However, knowledge gaps remain about the movement patterns of this species. Between 2007 and 2022, we deployed 17 satellite tags onto hawksbill turtles from scattered locations in the SWIO: 16 nesting females—Granitic Islands, Seychelles (n = 9); north Madagascar (n = 5); Moheli, Comoros (n = 1); Juan de Nova, Terres australes et antarctiques françaises (n = 1)—and 1 female bycaught in fisheries (east Madagascar). We found strong variability in migratory movements amongst individuals, particularly in terms of distance and movement persistence. Detailed analysis of movement persistence reveals that these individuals behave differently in neritic and oceanic habitats, with a lower movement persistence in neritic habitats. We identified a total of 12 foraging areas scattered throughout the SWIO, both in coastal and open-sea neritic habitats. These results reinforce the need to consider the importance of neritic habitats, for both migration and foraging, in conservation policies. The quantification of the degree of migratory variability is particularly important to developing conservation plans and strategies at both the national and international level, including the delineation of regional management units (RMUs) in the Indian Ocean.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140129726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Fernando Márquez-Farías, John P. Tyminski, George C. Fischer, Robert E. Hueter
ABSTRACT: Length at life stages of the white shark Carcharodon carcharias is not well known for most of the 9 populations of this species, including in the western North Atlantic (WNA). We analyzed length and maturity data by sex for 87 white sharks with sizes ranging 138-501 cm total length (TL), captured, studied, and released by OCEARCH during 2012-2022, off the US and Canadian Atlantic coasts. A binary logistic regression was used to estimate the length-at-maturity (L50) for the WNA white shark with a Bayesian statistical framework using a Markov chain Monte Carlo method for numerical integration. Different trials using noninformative and informative priors were tested. The posterior probability distribution for L50, steepness of the model (φ), and 95% credible intervals (CI) of the logistic model for females were L50 = 411.3 cm TL (CI: 390.8-432.6 cm TL) and φ = 10.5 (CI: 5.7-17.8) and for males were L50 = 334.9 cm TL (CI: 321.2-348.2 cm TL) and φ = 7.5 (CI: 4.2-12.4). These L50 values are somewhat smaller than previously reported sizes-at-maturity for both sexes of this species. An ordinal logistic regression allowed us to determine the probability of being in the various life stages (young-of-the-year, juvenile, and adult) at a particular size. Estimating the length at any life-history stage of white sharks along with age estimates is useful for determining the reproductive value of the population and ultimately for estimating the relative contribution (elasticity) of vital rates to population growth.
{"title":"Length at life stages of the white shark Carcharodon carcharias in the western North Atlantic","authors":"J. Fernando Márquez-Farías, John P. Tyminski, George C. Fischer, Robert E. Hueter","doi":"10.3354/esr01300","DOIUrl":"https://doi.org/10.3354/esr01300","url":null,"abstract":"ABSTRACT: Length at life stages of the white shark <i>Carcharodon carcharias</i> is not well known for most of the 9 populations of this species, including in the western North Atlantic (WNA). We analyzed length and maturity data by sex for 87 white sharks with sizes ranging 138-501 cm total length (TL), captured, studied, and released by OCEARCH during 2012-2022, off the US and Canadian Atlantic coasts. A binary logistic regression was used to estimate the length-at-maturity (<i>L</i><sub>50</sub>) for the WNA white shark with a Bayesian statistical framework using a Markov chain Monte Carlo method for numerical integration. Different trials using noninformative and informative priors were tested. The posterior probability distribution for <i>L</i><sub>50</sub>, steepness of the model (φ), and 95% credible intervals (CI) of the logistic model for females were <i>L</i><sub>50</sub> = 411.3 cm TL (CI: 390.8-432.6 cm TL) and φ = 10.5 (CI: 5.7-17.8) and for males were <i>L</i><sub>50</sub> = 334.9 cm TL (CI: 321.2-348.2 cm TL) and φ = 7.5 (CI: 4.2-12.4). These <i>L</i><sub>50</sub> values are somewhat smaller than previously reported sizes-at-maturity for both sexes of this species. An ordinal logistic regression allowed us to determine the probability of being in the various life stages (young-of-the-year, juvenile, and adult) at a particular size. Estimating the length at any life-history stage of white sharks along with age estimates is useful for determining the reproductive value of the population and ultimately for estimating the relative contribution (elasticity) of vital rates to population growth.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140010226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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