Marcos D. Calle-Morán, Héctor M. Erazo-Garcés, Ana R. Hernández-Téllez, Felipe Galván-Magaña, Colombo Estupiñán-Montaño
{"title":"Feeding ecology of the shortfin mako shark, Isurus oxyrinchus, in the Ecuadorian Pacific Ocean","authors":"Marcos D. Calle-Morán, Héctor M. Erazo-Garcés, Ana R. Hernández-Téllez, Felipe Galván-Magaña, Colombo Estupiñán-Montaño","doi":"10.1017/s0025315423000863","DOIUrl":null,"url":null,"abstract":"<p>Shortfin mako shark, <span>Isurus oxyrinchus</span>, is listed as an endangered species with declining global population. Thus, studies regarding its biology and ecology are important to recommend fishery management and conservation measures. This study aimed to determine the diet composition and feeding habits of <span>I. oxyrinchus</span> in Ecuadorian waters. Samples were obtained from Santa Rosa fishing port (Ecuador). The total length (L<span>T</span>), sex and sexual characteristics were recorded, and stomach contents were collected. A total of 142 individuals were recorded, comprising 81 females (104–295 cm L<span>T</span>) and 61 males (127–245 cm L<span>T</span>). A total of 24 prey species were identified, including crustaceans, cephalopods, teleosts and cetaceans. According to the Prey-Specific Index of Relative Importance (PSIRI), the main prey taxa were the ommastrephid squid, <span>Dosidicus gigas</span> (42.57%) and <span>Sthenoteuthis oualaniensis</span> (21.04%), followed by fish from the family Hemiramphidae (11.85%). <span>Isurus oxyrinchus</span> is a specialist predator that preferred a low number of prey (<span>Bi</span> = 0.25), both by sex (<span>Bi</span>; females = 0.29 and males = 0.34) and life stages (<span>Bi</span>; juveniles = 0.27 and adults = 0.37). The trophic overlap was medium for sexes (<span>J</span> = 0.54) and biological cycle phases (<span>J</span> = 0.42). Trophic level (<span>TL<span>k</span></span>) was 4.47, indicating that <span>I. oxyrinchus</span> is a tertiary predator. This information will help in fisheries management based on an ecosystem approach, where this species fulfils an ecological role, and its interactions with other species allow us to understand how the flow of nutrients and energy occurs within an ecosystem.</p>","PeriodicalId":17477,"journal":{"name":"Journal of the Marine Biological Association of the United Kingdom","volume":"1 1","pages":""},"PeriodicalIF":1.1000,"publicationDate":"2023-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the Marine Biological Association of the United Kingdom","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1017/s0025315423000863","RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MARINE & FRESHWATER BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Shortfin mako shark, Isurus oxyrinchus, is listed as an endangered species with declining global population. Thus, studies regarding its biology and ecology are important to recommend fishery management and conservation measures. This study aimed to determine the diet composition and feeding habits of I. oxyrinchus in Ecuadorian waters. Samples were obtained from Santa Rosa fishing port (Ecuador). The total length (LT), sex and sexual characteristics were recorded, and stomach contents were collected. A total of 142 individuals were recorded, comprising 81 females (104–295 cm LT) and 61 males (127–245 cm LT). A total of 24 prey species were identified, including crustaceans, cephalopods, teleosts and cetaceans. According to the Prey-Specific Index of Relative Importance (PSIRI), the main prey taxa were the ommastrephid squid, Dosidicus gigas (42.57%) and Sthenoteuthis oualaniensis (21.04%), followed by fish from the family Hemiramphidae (11.85%). Isurus oxyrinchus is a specialist predator that preferred a low number of prey (Bi = 0.25), both by sex (Bi; females = 0.29 and males = 0.34) and life stages (Bi; juveniles = 0.27 and adults = 0.37). The trophic overlap was medium for sexes (J = 0.54) and biological cycle phases (J = 0.42). Trophic level (TLk) was 4.47, indicating that I. oxyrinchus is a tertiary predator. This information will help in fisheries management based on an ecosystem approach, where this species fulfils an ecological role, and its interactions with other species allow us to understand how the flow of nutrients and energy occurs within an ecosystem.
期刊介绍:
JMBA is an international journal, publishing original research on all aspects of marine biology. It includes pioneering work taking place today on major issues concerning marine organisms and their environment. Subjects covered include: ecological surveys and population studies of marine communities; physiology and experimental biology; taxonomy, morphology and life history of marine animals and plants; and chemical and physical oceanographic work. Included with 2010 online subscriptions: Marine Biodiversity Records.