Luis Medrano-González, Katherina Audley, Charles Scott Baker, Debbie Steel
ABSTRACT: Here, we describe variation in mtDNA haplotypes among 22 individual humpback whales off the Guerrero coast in southern Mexico and compare this to other wintering regions in the eastern North Pacific Ocean using published data. After correcting for different sample sizes, Guerrero humpback whales fit the cline in the eastern North Pacific in which A types are more abundant northwards, while E and F types are more abundant southwards. Whales observed around Guerrero in early winter exhibited a greater frequency of F types that are also observed earlier in winter at Bahía de Banderas in the mainland region, suggesting a seasonal passage of whales from Mexico to Central America. Four diversity indices were higher in different wintering regions between Nayarit and Guerrero. Departures from neutrality were observed in the bordering wintering grounds of the region. Four measures of differentiation by distance indicated boundaries between Nayarit and Southern Jalisco, and between Guerrero and Oaxaca, suggesting a transitional region between wintering regions of Mexico and Central America from 17.5° to 19.5°N.
{"title":"mtDNA variation of humpback whales in their wintering grounds of Guerrero, southern Mexican Pacific","authors":"Luis Medrano-González, Katherina Audley, Charles Scott Baker, Debbie Steel","doi":"10.3354/esr01332","DOIUrl":"https://doi.org/10.3354/esr01332","url":null,"abstract":"ABSTRACT: Here, we describe variation in mtDNA haplotypes among 22 individual humpback whales off the Guerrero coast in southern Mexico and compare this to other wintering regions in the eastern North Pacific Ocean using published data. After correcting for different sample sizes, Guerrero humpback whales fit the cline in the eastern North Pacific in which A types are more abundant northwards, while E and F types are more abundant southwards. Whales observed around Guerrero in early winter exhibited a greater frequency of F types that are also observed earlier in winter at Bahía de Banderas in the mainland region, suggesting a seasonal passage of whales from Mexico to Central America. Four diversity indices were higher in different wintering regions between Nayarit and Guerrero. Departures from neutrality were observed in the bordering wintering grounds of the region. Four measures of differentiation by distance indicated boundaries between Nayarit and Southern Jalisco, and between Guerrero and Oaxaca, suggesting a transitional region between wintering regions of Mexico and Central America from 17.5° to 19.5°N.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141507393","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}
Sean Evans, Melissa J Schulze, Mark Brown, Jeanne A. Mortimer
ABSTRACT: Decreasing body size in nesting sea turtles has been documented globally in recent decades and attributed to a combination of environmental, ecological, and demographic changes, along with concerns about potential negative consequences for reproductive output. Our study examines long-term trends in body size of nesting hawksbill turtles Eretmochelys imbricata in the Seychelles and the likely demographic factors that may be responsible. The average curved carapace length (CCL) declined significantly from 1974-2022 (0.05 cm yr-1) for females nesting at 2 neighbouring islands, Cousine and Cousin. At Cousine Island, adult growth rates were calculated, and neophyte (recruit) and remigrant nesters were distinguished from 2002-2022. Growth was significantly different from 0 (0.18 cm yr-1). Neophyte CCL declined significantly (0.19 cm yr-1), while CCL of returning remigrants increased significantly (0.12 cm yr-1). The annual number and proportion of neophytes and remigrants fluctuated throughout 2002-2022, but the proportion of neophytes significantly increased from 2013 onward, approximately 20 yr after complete protection and increased hatchling production began at Cousine. Clutch size correlated positively with CCL, and annual clutch numbers have been increasing significantly since 1992. We conclude that overall declining trends in body size likely result from declining neophyte CCLs combined with increasing proportions of neophytes over the last decade. Meanwhile, conservation measures have enabled neophytes to survive to breed repeatedly during multiple nesting seasons and, over time, to grow bigger, produce larger egg clutches, and ultimately enhance the reproductive output of the entire population.
{"title":"Nesting female hawksbill sea turtles trending smaller in the western Indian Ocean","authors":"Sean Evans, Melissa J Schulze, Mark Brown, Jeanne A. Mortimer","doi":"10.3354/esr01334","DOIUrl":"https://doi.org/10.3354/esr01334","url":null,"abstract":"ABSTRACT: Decreasing body size in nesting sea turtles has been documented globally in recent decades and attributed to a combination of environmental, ecological, and demographic changes, along with concerns about potential negative consequences for reproductive output. Our study examines long-term trends in body size of nesting hawksbill turtles <i>Eretmochelys imbricata</i> in the Seychelles and the likely demographic factors that may be responsible. The average curved carapace length (CCL) declined significantly from 1974-2022 (0.05 cm yr<sup>-1</sup>) for females nesting at 2 neighbouring islands, Cousine and Cousin. At Cousine Island, adult growth rates were calculated, and neophyte (recruit) and remigrant nesters were distinguished from 2002-2022. Growth was significantly different from 0 (0.18 cm yr<sup>-1</sup>). Neophyte CCL declined significantly (0.19 cm yr<sup>-1</sup>), while CCL of returning remigrants increased significantly (0.12 cm yr<sup>-1</sup>). The annual number and proportion of neophytes and remigrants fluctuated throughout 2002-2022, but the proportion of neophytes significantly increased from 2013 onward, approximately 20 yr after complete protection and increased hatchling production began at Cousine. Clutch size correlated positively with CCL, and annual clutch numbers have been increasing significantly since 1992. We conclude that overall declining trends in body size likely result from declining neophyte CCLs combined with increasing proportions of neophytes over the last decade. Meanwhile, conservation measures have enabled neophytes to survive to breed repeatedly during multiple nesting seasons and, over time, to grow bigger, produce larger egg clutches, and ultimately enhance the reproductive output of the entire population.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141517969","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}
Maximillian P. T. G. Tercel, Jordan P. Cuff, Ian P. Vaughan, William O. C. Symondson, Martine Goder, Sunil Matadeen, Vikash Tatayah, Nik C. Cole
ABSTRACT: The Serpent Island centipede Scolopendra abnormis is a threatened centipede species found on only 2 small islands in the Indian Ocean: Round Island, located 22.5 km northeast of Mauritius, and Serpent Island, 4 km northwest of Round Island. Current understanding of its ecology is based on limited direct observations from 30 yr ago. Round Island has since undergone significant habitat restoration. Hyperabundant non-native ants are also present, which may impact centipede nesting behaviour, ecology, and survival. Recent methodological advances, such as high-throughput sequencing of dietary DNA, can extend our understanding of invertebrate ecology and provide data complementary to direct observation. Using a combination of dietary metabarcoding and observational approaches, we provide new insights into the ecology and natural history of this threatened invertebrate predator. S. abnormis nest most consistently in the root network found beneath endemic Pandanus vandermeeschii trees. They are also found in areas with good soil cover, herbaceous growth, and areas of bare rock slab. Only 4 of 43 centipedes in this study were found near an ant foraging trail, which may have significant implications for S. abnormis nesting habits. These centipedes primarily consume insect prey (particularly taxa within Lepidoptera, Hymenoptera, Diptera), irrespective of centipede body size. A quarter of centipedes also consumed endemic lizards. We also found marked differences in diet composition between wet and dry seasons arising from the changing availability of prey. We provide additional natural history observations and conclude by suggesting conservation actions that would help better understand and safeguard S. abnormis populations.
{"title":"Ecology, natural history, and conservation status of Scolopendra abnormis, a threatened centipede endemic to Mauritius","authors":"Maximillian P. T. G. Tercel, Jordan P. Cuff, Ian P. Vaughan, William O. C. Symondson, Martine Goder, Sunil Matadeen, Vikash Tatayah, Nik C. Cole","doi":"10.3354/esr01337","DOIUrl":"https://doi.org/10.3354/esr01337","url":null,"abstract":"ABSTRACT: The Serpent Island centipede <i>Scolopendra abnormis</i> is a threatened centipede species found on only 2 small islands in the Indian Ocean: Round Island, located 22.5 km northeast of Mauritius, and Serpent Island, 4 km northwest of Round Island. Current understanding of its ecology is based on limited direct observations from 30 yr ago. Round Island has since undergone significant habitat restoration. Hyperabundant non-native ants are also present, which may impact centipede nesting behaviour, ecology, and survival. Recent methodological advances, such as high-throughput sequencing of dietary DNA, can extend our understanding of invertebrate ecology and provide data complementary to direct observation. Using a combination of dietary metabarcoding and observational approaches, we provide new insights into the ecology and natural history of this threatened invertebrate predator. <i>S. abnormis</i> nest most consistently in the root network found beneath endemic <i>Pandanus vandermeeschii</i> trees. They are also found in areas with good soil cover, herbaceous growth, and areas of bare rock slab. Only 4 of 43 centipedes in this study were found near an ant foraging trail, which may have significant implications for <i>S. abnormis</i> nesting habits. These centipedes primarily consume insect prey (particularly taxa within Lepidoptera, Hymenoptera, Diptera), irrespective of centipede body size. A quarter of centipedes also consumed endemic lizards. We also found marked differences in diet composition between wet and dry seasons arising from the changing availability of prey. We provide additional natural history observations and conclude by suggesting conservation actions that would help better understand and safeguard <i>S. abnormis</i> populations.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529488","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}
Alberto Hernandez-Gonzalez, Camilo Saavedra, Fiona L. Read, Alfredo López, Anabela Gouveia, Pablo Covelo, Alexandre Alonso-Fernández, Francisco Velasco, M. Begoña Santos, Graham J. Pierce
ABSTRACT: Diet studies on the endangered and genetically distinct Iberian population of the southern harbour porpoise Phocoena phocoena are scarce. The present study provides updated information on the feeding ecology of this cetacean along the Galician coast (NW Spain) over the last 3 decades (1990-2018). The stomach contents of 72 stranded harbour porpoises were analysed to determine diet composition, to study which factors affect dietary variability and to estimate overlap between harbour porpoise diet and the target species of the fisheries in the study area, one of the most important fishing regions in Europe. Results showed that harbour porpoises are mainly piscivorous. We identified 33 prey taxa, but only 4 were important in the diet: fish of the genus Trisopterus, blue whiting Micromesistius poutassou, Atlantic horse mackerel Trachurus trachurus and European hake Merluccius merluccius. Interannual and ontogenetic variability in the diet were statistically significant, although differences in diet between sexes or between seasons were not detected. The diet of harbour porpoises from the Galician coast shows a partial overlap with fisheries catches in the area in terms of commercial fish species (≈61%) and size classes (≈45%), confirming the potential vulnerability of the Iberian population to interactions with fishing activities (i.e. bycatch in fishing gear and/or reduced prey availability).
{"title":"Feeding ecology of harbour porpoises Phocoena phocoena stranded on the Galician coast (NW Spain) between 1990 and 2018","authors":"Alberto Hernandez-Gonzalez, Camilo Saavedra, Fiona L. Read, Alfredo López, Anabela Gouveia, Pablo Covelo, Alexandre Alonso-Fernández, Francisco Velasco, M. Begoña Santos, Graham J. Pierce","doi":"10.3354/esr01328","DOIUrl":"https://doi.org/10.3354/esr01328","url":null,"abstract":"ABSTRACT: Diet studies on the endangered and genetically distinct Iberian population of the southern harbour porpoise <i>Phocoena phocoena</i> are scarce. The present study provides updated information on the feeding ecology of this cetacean along the Galician coast (NW Spain) over the last 3 decades (1990-2018). The stomach contents of 72 stranded harbour porpoises were analysed to determine diet composition, to study which factors affect dietary variability and to estimate overlap between harbour porpoise diet and the target species of the fisheries in the study area, one of the most important fishing regions in Europe. Results showed that harbour porpoises are mainly piscivorous. We identified 33 prey taxa, but only 4 were important in the diet: fish of the genus <i>Trisopterus</i>, blue whiting <i>Micromesistius poutassou</i>, Atlantic horse mackerel <i>Trachurus trachurus</i> and European hake <i>Merluccius merluccius</i>. Interannual and ontogenetic variability in the diet were statistically significant, although differences in diet between sexes or between seasons were not detected. The diet of harbour porpoises from the Galician coast shows a partial overlap with fisheries catches in the area in terms of commercial fish species (≈61%) and size classes (≈45%), confirming the potential vulnerability of the Iberian population to interactions with fishing activities (i.e. bycatch in fishing gear and/or reduced prey availability).","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197568","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}
Cory J. D. Matthews, Fred J. Longstaffe, Geneviève J. Parent, Claire A. Hornby, Cortney A. Watt
ABSTRACT: In the eastern Canadian Arctic, belugas Delphinapterus leucas exhibit genetic and ecological differentiation across their distribution that forms the basis of management stocks for traditional Inuit hunts. Using oxygen and stable carbon isotope ratios in dentine phosphate (δ18OP) and structural carbonate (δ13CSC), respectively, we evaluated the spatial structure of 3 of these beluga stocks: Western Hudson Bay (WHB, n = 30), Cumberland Sound (CS, n = 44), and Eastern High Arctic-Baffin Bay (EHA-BB, n = 29). Pairwise comparisons revealed significant differences in δ18OP and Suess-adjusted δ13CSC among all stocks, with the exception of similar δ18OP between the WHB and CS stocks. A linear discriminant analysis (LDA) model fit to 60% of the data set (training data) successfully classified 84% of the remaining belugas (test data) to their respective stocks based on hunt location. Isotopic overlap among stocks could reflect (1) homogeneous baseline stable isotope (SI) composition between geographically adjacent stocks, (2) some degree of marginal geographic overlap in ranges or individual movements among stocks, perhaps during late spring, or (3) confounding dietary influences that increased within-stock SI variation. Some misclassifications consistent with individual movements among stocks were supported by limited genetic data, with a small number of belugas hunted from the CS stock exhibiting both isotopic and genetic similarity to WHB belugas. Geographic stock differentiation inferred from oxygen and carbon isotope proxies largely corroborates current eastern Canadian Arctic beluga stock definitions, which is relevant not only for management purposes but also for monitoring changing beluga distributions in response to ongoing climate-driven changes in Arctic marine ecosystems.
{"title":"Discriminating Canadian Arctic beluga management stocks using dentine oxygen and carbon isotopes","authors":"Cory J. D. Matthews, Fred J. Longstaffe, Geneviève J. Parent, Claire A. Hornby, Cortney A. Watt","doi":"10.3354/esr01333","DOIUrl":"https://doi.org/10.3354/esr01333","url":null,"abstract":"ABSTRACT: In the eastern Canadian Arctic, belugas <i>Delphinapterus leucas</i> exhibit genetic and ecological differentiation across their distribution that forms the basis of management stocks for traditional Inuit hunts. Using oxygen and stable carbon isotope ratios in dentine phosphate (δ<sup>18</sup>O<sub>P</sub>) and structural carbonate (δ<sup>13</sup>C<sub>SC</sub>), respectively, we evaluated the spatial structure of 3 of these beluga stocks: Western Hudson Bay (WHB, n = 30), Cumberland Sound (CS, n = 44), and Eastern High Arctic-Baffin Bay (EHA-BB, n = 29). Pairwise comparisons revealed significant differences in δ<sup>18</sup>O<sub>P</sub> and Suess-adjusted δ<sup>13</sup>C<sub>SC</sub> among all stocks, with the exception of similar δ<sup>18</sup>O<sub>P</sub> between the WHB and CS stocks. A linear discriminant analysis (LDA) model fit to 60% of the data set (training data) successfully classified 84% of the remaining belugas (test data) to their respective stocks based on hunt location. Isotopic overlap among stocks could reflect (1) homogeneous baseline stable isotope (SI) composition between geographically adjacent stocks, (2) some degree of marginal geographic overlap in ranges or individual movements among stocks, perhaps during late spring, or (3) confounding dietary influences that increased within-stock SI variation. Some misclassifications consistent with individual movements among stocks were supported by limited genetic data, with a small number of belugas hunted from the CS stock exhibiting both isotopic and genetic similarity to WHB belugas. Geographic stock differentiation inferred from oxygen and carbon isotope proxies largely corroborates current eastern Canadian Arctic beluga stock definitions, which is relevant not only for management purposes but also for monitoring changing beluga distributions in response to ongoing climate-driven changes in Arctic marine ecosystems.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197575","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: Leatherback turtles Dermochelys coriacea are a pelagic species, globally endangered due to multiple anthropogenic impacts. Although protected under Australian legislation, species-specific practical protection has been hampered by sparse information about leatherback distribution in Australian waters. To fill this gap, we obtained records of leatherback interactions with fisheries gear, opportunistic sightings at sea, beach stranding events and non-target capture in shark control programs. We evaluated the temporal and geographic distribution of records and assessed potential bias in observation opportunity based on human population density and fishery activity. Based on 1073 leatherback observations from 1990 to 2022, we found that sightings were unevenly distributed right around Australia, encompassing longitudes from 105.4°E to 165.1°E and latitudes from 43.7°S to 10°S. In the extreme southeast of Australia, hotspots were apparent during December to March (austral summer). In temperate and subtropical latitudes to the west and east of Australia, hotspots appeared predominantly during June, July and August (austral winter), but were also apparent, albeit weaker, to the east in all other months. Our results confirm that the species is present around Australia in all months of the year and has a much wider geographic and offshore distribution around Australia than previously reported. Hence, we inferred that Australian waters are highly important for migrating and foraging leatherbacks from subpopulations breeding in the Pacific and Indian Oceans, all of which are at high risk of extinction, and we suggest that Australian management agencies have crucial roles in protecting these endangered animals.
{"title":"Occurrence of leatherback turtles around Australia","authors":"Julia Hazel, Mark Hamann, Ian Bell, Rachel Groom","doi":"10.3354/esr01331","DOIUrl":"https://doi.org/10.3354/esr01331","url":null,"abstract":"ABSTRACT: Leatherback turtles <i>Dermochelys coriacea</i> are a pelagic species, globally endangered due to multiple anthropogenic impacts. Although protected under Australian legislation, species-specific practical protection has been hampered by sparse information about leatherback distribution in Australian waters. To fill this gap, we obtained records of leatherback interactions with fisheries gear, opportunistic sightings at sea, beach stranding events and non-target capture in shark control programs. We evaluated the temporal and geographic distribution of records and assessed potential bias in observation opportunity based on human population density and fishery activity. Based on 1073 leatherback observations from 1990 to 2022, we found that sightings were unevenly distributed right around Australia, encompassing longitudes from 105.4°E to 165.1°E and latitudes from 43.7°S to 10°S. In the extreme southeast of Australia, hotspots were apparent during December to March (austral summer). In temperate and subtropical latitudes to the west and east of Australia, hotspots appeared predominantly during June, July and August (austral winter), but were also apparent, albeit weaker, to the east in all other months. Our results confirm that the species is present around Australia in all months of the year and has a much wider geographic and offshore distribution around Australia than previously reported. Hence, we inferred that Australian waters are highly important for migrating and foraging leatherbacks from subpopulations breeding in the Pacific and Indian Oceans, all of which are at high risk of extinction, and we suggest that Australian management agencies have crucial roles in protecting these endangered animals.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197683","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}
Adriana Gonzalez-Pestana, Joanna Alfaro-Shigueto, Ximena Velez-Zuazo, Jeffrey C. Mangel
ABSTRACT: This review examines—with a focus on Peru—the distribution, life-history, ecology, fisheries, historic and contemporary cultural importance, commerce, and management of the Pacific guitarfish Pseudobatos planiceps. In the eastern Pacific, Peru represents its most important habitats. The only 2 identified Important Shark and Ray Areas for this species are in Peru for feeding purposes. Other critical habitats are unidentified (e.g. reproductive). Most demographic parameters are unknown, since only length-at-maturity and fecundity have been determined. This species is a mesopredator that feeds on benthic invertebrates but also on Peruvian anchoveta. This trophic plasticity is unique among species within this genus. Globally, Peru has one of the longest species-specific landing datasets (56 yr) and one of the largest catches among countries that report guitarfish landings. This dataset shows a 98% decrease in landings from a peak in 1981 to a low in 2004, while fishing effort increased during this period, suggesting that depletion occurred in the early 1980s. The Pacific guitarfish is the third most landed ray species by artisanal fisheries in Peru, mainly between the central and northern regions. Adults are mainly caught using gillnets and as bycatch in trawling fisheries. Mid-northern Peru has a millennia-old tradition in Pacific guitarfish capture and consumption, and catch is not regulated. Along its distributional range, fisheries in Peru are the main cause of population decline; therefore, there is an urgency to halt this trend to protect the Pacific guitarfish. This review establishes a baseline, identifies information gaps, and provides recommendations to guide research and management for the species.
{"title":"Natural history, fisheries, and conservation of the Pacific guitarfish: signs of trouble in Peruvian waters","authors":"Adriana Gonzalez-Pestana, Joanna Alfaro-Shigueto, Ximena Velez-Zuazo, Jeffrey C. Mangel","doi":"10.3354/esr01329","DOIUrl":"https://doi.org/10.3354/esr01329","url":null,"abstract":"ABSTRACT: This review examines—with a focus on Peru—the distribution, life-history, ecology, fisheries, historic and contemporary cultural importance, commerce, and management of the Pacific guitarfish <i>Pseudobatos planiceps</i>. In the eastern Pacific, Peru represents its most important habitats. The only 2 identified Important Shark and Ray Areas for this species are in Peru for feeding purposes. Other critical habitats are unidentified (e.g. reproductive). Most demographic parameters are unknown, since only length-at-maturity and fecundity have been determined. This species is a mesopredator that feeds on benthic invertebrates but also on Peruvian anchoveta. This trophic plasticity is unique among species within this genus. Globally, Peru has one of the longest species-specific landing datasets (56 yr) and one of the largest catches among countries that report guitarfish landings. This dataset shows a 98% decrease in landings from a peak in 1981 to a low in 2004, while fishing effort increased during this period, suggesting that depletion occurred in the early 1980s. The Pacific guitarfish is the third most landed ray species by artisanal fisheries in Peru, mainly between the central and northern regions. Adults are mainly caught using gillnets and as bycatch in trawling fisheries. Mid-northern Peru has a millennia-old tradition in Pacific guitarfish capture and consumption, and catch is not regulated. Along its distributional range, fisheries in Peru are the main cause of population decline; therefore, there is an urgency to halt this trend to protect the Pacific guitarfish. This review establishes a baseline, identifies information gaps, and provides recommendations to guide research and management for the species.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141197578","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}
Lance P. Garrison, Melissa S. Soldevilla, Anthony Martinez, Keith D. Mullin
ABSTRACT: The newly recognized Rice’s whale Balaenoptera ricei is among the most endangered large whale species in the world and primarily occupies a region near the continental shelf break in the northeastern Gulf of Mexico (GoMex). We analyzed visual line-transect survey data collected throughout the northern GoMex from 2003-2019 and developed spatially explicit density maps using a density surface modeling approach to examine relationships between Rice’s whale density and bathymetric and oceanographic features. We identified water depth, surface chl a concentration, bottom temperature, and bottom salinity as key parameters that define the Rice’s whale habitat. This is consistent with upwelling of cold, high-salinity water along the continental shelf break and seasonal input of high-productivity surface water originating from coastal sources. The dominant circulation patterns in the GoMex, including the presence of Loop Current eddies, lead to increased productivity and likely play a role in maintaining high densities of forage species needed to support Rice’s whales. Extrapolation of the model suggests additional regions in Mexican waters of GoMex that may be suitable for Rice’s whales. This study informs the designation of critical habitat as defined by the US Endangered Species Act and will assist in marine spatial planning activities to avoid additional anthropogenic impacts to Rice’s whales associated with the development of wind energy and aquaculture.
摘要：新发现的莱斯鲸（Balaenoptera ricei）是世界上最濒危的大型鲸鱼物种之一，主要栖息在墨西哥湾（GoMex）东北部大陆架断裂附近的区域。我们分析了 2003-2019 年期间在整个墨西哥湾北部收集到的目测线描调查数据，并利用密度面建模方法绘制了空间明确的密度图，以研究米氏鲸密度与水深和海洋学特征之间的关系。我们发现水深、表层 chl a 浓度、底层温度和底层盐度是界定大米鲸栖息地的关键参数。这与沿大陆架断裂上涌的高盐度冷水和来自沿海的高产表层水的季节性输入是一致的。墨西哥湾的主要环流模式，包括环流漩涡的存在，导致了生产力的提高，并可能在维持赖斯鲸所需的高密度觅食物种方面发挥作用。对模型的推断表明，墨西哥湾墨西哥水域还有更多区域可能适合大米鲸的生存。这项研究为指定美国《濒危物种法》规定的重要栖息地提供了信息，并将有助于海洋空间规划活动，以避免风能开发和水产养殖对大米鲸造成额外的人为影响。
{"title":"A density surface model describing the habitat of the Critically Endangered Rice’s whale Balaenoptera ricei in the Gulf of Mexico","authors":"Lance P. Garrison, Melissa S. Soldevilla, Anthony Martinez, Keith D. Mullin","doi":"10.3354/esr01324","DOIUrl":"https://doi.org/10.3354/esr01324","url":null,"abstract":"ABSTRACT: The newly recognized Rice’s whale <i>Balaenoptera ricei</i> is among the most endangered large whale species in the world and primarily occupies a region near the continental shelf break in the northeastern Gulf of Mexico (GoMex). We analyzed visual line-transect survey data collected throughout the northern GoMex from 2003-2019 and developed spatially explicit density maps using a density surface modeling approach to examine relationships between Rice’s whale density and bathymetric and oceanographic features. We identified water depth, surface chl <i>a</i> concentration, bottom temperature, and bottom salinity as key parameters that define the Rice’s whale habitat. This is consistent with upwelling of cold, high-salinity water along the continental shelf break and seasonal input of high-productivity surface water originating from coastal sources. The dominant circulation patterns in the GoMex, including the presence of Loop Current eddies, lead to increased productivity and likely play a role in maintaining high densities of forage species needed to support Rice’s whales. Extrapolation of the model suggests additional regions in Mexican waters of GoMex that may be suitable for Rice’s whales. This study informs the designation of critical habitat as defined by the US Endangered Species Act and will assist in marine spatial planning activities to avoid additional anthropogenic impacts to Rice’s whales associated with the development of wind energy and aquaculture.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881655","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 A. Richards, Christopher Cvitanovic, Michael Dunlop, Sabrina Fossette, Linda Thomas, Anton D. Tucker, E. Ingrid van Putten, Andrea U. Whiting, Scott D. Whiting, Alistair J. Hobday
ABSTRACT: Sea turtles worldwide face a range of threats including sea level rise and warming associated with climate change, predation by invasive species, plastic and light pollution, coastal development, and human interference. Conservation managers have a long history of aiding sea turtle populations, from protecting nests to head-starting hatchlings. Due to these challenges faced by turtles, there is a constant focus on assessing the likely success of proposed conservation interventions to help inform decision-making processes. We develop an age-based, spatially implicit population model for the north-west shelf stock of Australia’s endemic flatback turtle Natator depressus that estimates the long-term outcomes of a range of onshore and offshore conservation interventions. Analysis of the model shows that young adults contribute most to population growth (i.e. have highest expected future reproductive success); however, this is often the most difficult life stage to manipulate in the field. Observable outcomes of interventions are often delayed for many years, especially for on shore activities (e.g. protecting eggs and hatchlings), due to late age to maturity. The potential impact of warming-induced female bias on population dynamics was also investigated. Although such bias increases population growth rates in the short term, negative effects of the bias (e.g. reduced female mating success) and negative environmental effects (e.g. reduced survival rates, habitat loss) can lead to sustained declines. Population models can rapidly assess climate change and conservation impacts on turtle dynamics and can guide monitoring efforts for real-world application.
{"title":"Identifying impactful sea turtle conservation strategies: a mismatch between most influential and most readily manageable life-stages","authors":"Shane A. Richards, Christopher Cvitanovic, Michael Dunlop, Sabrina Fossette, Linda Thomas, Anton D. Tucker, E. Ingrid van Putten, Andrea U. Whiting, Scott D. Whiting, Alistair J. Hobday","doi":"10.3354/esr01326","DOIUrl":"https://doi.org/10.3354/esr01326","url":null,"abstract":"ABSTRACT: Sea turtles worldwide face a range of threats including sea level rise and warming associated with climate change, predation by invasive species, plastic and light pollution, coastal development, and human interference. Conservation managers have a long history of aiding sea turtle populations, from protecting nests to head-starting hatchlings. Due to these challenges faced by turtles, there is a constant focus on assessing the likely success of proposed conservation interventions to help inform decision-making processes. We develop an age-based, spatially implicit population model for the north-west shelf stock of Australia’s endemic flatback turtle <i>Natator depressus</i> that estimates the long-term outcomes of a range of onshore and offshore conservation interventions. Analysis of the model shows that young adults contribute most to population growth (i.e. have highest expected future reproductive success); however, this is often the most difficult life stage to manipulate in the field. Observable outcomes of interventions are often delayed for many years, especially for on shore activities (e.g. protecting eggs and hatchlings), due to late age to maturity. The potential impact of warming-induced female bias on population dynamics was also investigated. Although such bias increases population growth rates in the short term, negative effects of the bias (e.g. reduced female mating success) and negative environmental effects (e.g. reduced survival rates, habitat loss) can lead to sustained declines. Population models can rapidly assess climate change and conservation impacts on turtle dynamics and can guide monitoring efforts for real-world application.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881557","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}
Alistair J. Hobday, E. Ingrid van Putten, Christopher Cvitanovic, Michael Dunlop, Sabrina Fossette, Sierra Ison, Shane A. Richards, Linda Thomas, Paris Tuohy, Ruby Annand-Jones, Tony Tucker, Scott Whiting
ABSTRACT: Australia’s endemic flatback turtle Natator depressus is the focus of a long-term conservation program aimed at securing the persistence of healthy populations in the northwest of Australia into the future. Primary threats to flatback turtles include (1) sea level rise, (2) predation from introduced species, (3) temperature increases, (4) onshore and nearshore light, (5) marine debris, and (6) modification to beaches. Population declines resulting from these threats have been reported or are anticipated, and a range of intervention options are possible that may limit their negative impact. Following methods previously developed and applied to iconic marine species and habitats, we generated a range of intervention options, and asked experts to prioritise those actions using an intervention prioritisation tool (IPT) and the public to prioritise based on social acceptability assessment (SAS). The IPT allows different conservation interventions to be assessed based on their economic cost, implementation feasibility, social acceptability, and perceived effectiveness in maintaining or increasing future turtle populations while simultaneously accounting for expert confidence in their assessment. Results generated by the IPT and SAS can be explored further to resolve uncertainty, a process that can help managers and experts alike in their decision-making process associated with flatback conservation. While this paper is focused on interventions relating to flatback turtles, we propose that our IPT can be applied in different settings to enable consideration of interventions for a range of threatened species and habitats to guide research and conservation investment decisions by managers.
{"title":"Flatback futures—evaluating conservation interventions to reduce threats to an endemic Australian turtle","authors":"Alistair J. Hobday, E. Ingrid van Putten, Christopher Cvitanovic, Michael Dunlop, Sabrina Fossette, Sierra Ison, Shane A. Richards, Linda Thomas, Paris Tuohy, Ruby Annand-Jones, Tony Tucker, Scott Whiting","doi":"10.3354/esr01321","DOIUrl":"https://doi.org/10.3354/esr01321","url":null,"abstract":"ABSTRACT: Australia’s endemic flatback turtle <i>Natator depressus</i> is the focus of a long-term conservation program aimed at securing the persistence of healthy populations in the northwest of Australia into the future. Primary threats to flatback turtles include (1) sea level rise, (2) predation from introduced species, (3) temperature increases, (4) onshore and nearshore light, (5) marine debris, and (6) modification to beaches. Population declines resulting from these threats have been reported or are anticipated, and a range of intervention options are possible that may limit their negative impact. Following methods previously developed and applied to iconic marine species and habitats, we generated a range of intervention options, and asked experts to prioritise those actions using an intervention prioritisation tool (IPT) and the public to prioritise based on social acceptability assessment (SAS). The IPT allows different conservation interventions to be assessed based on their economic cost, implementation feasibility, social acceptability, and perceived effectiveness in maintaining or increasing future turtle populations while simultaneously accounting for expert confidence in their assessment. Results generated by the IPT and SAS can be explored further to resolve uncertainty, a process that can help managers and experts alike in their decision-making process associated with flatback conservation. While this paper is focused on interventions relating to flatback turtles, we propose that our IPT can be applied in different settings to enable consideration of interventions for a range of threatened species and habitats to guide research and conservation investment decisions by managers.","PeriodicalId":48746,"journal":{"name":"Endangered Species Research","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881647","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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