squalus acanthias
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2021 ◽  
Vol 8 ◽  
Author(s):  
Krista van der Linde ◽  
Ingrid N. Visser ◽  
Rick Bout ◽  
Chris Lalas ◽  
Lara Shepherd ◽  
...  

Leopard seals (Hydrurga leptonyx) are top-order predators that prey on a wide variety of species including crustaceans, cephalopods, fishes, birds, and pinnipeds. While multiple diet studies have been conducted worldwide, there are no previous accounts of leopard seals predating on chondrichthyans. As part of a wider study on the diet of leopard seals in New Zealand (NZ) waters, researchers and citizen scientists recorded 39 observations of predation and collected 127 scats (166 total records) between 1942 and 2019. Predation on chondrichthyans was detected in 23.1% (n = 9) of observations of predation and 7.1% (n = 9) of scats (the latter via morphological examination and DNA sequencing). From both observations of predations and scats, three chondrichthyan species or genus were identified; elephantfish (Callorhinchus milii), ghost sharks (Hydrolagus spp.) and spiny dogfish (Squalus acanthias). While this is the first published record of leopard seals feeding on chondrichthyans, the relatively high frequency of occurrence within our NZ records, and that certain individuals appeared to target this type of prey, indicates that these species could constitute a substantial, or important, part of the diet for some leopard seals in this region. As chondrichthyans form an important part of the NZ marine ecosystems, our recognition of an additional top-order predator of these species contributes to understanding the overall health of, and future impacts of predators on, the wider NZ marine ecosystem.


2021 ◽  
Vol 1 (4) ◽  
pp. 131-143
Author(s):  
Edris Queiroz Lopes ◽  
Tais Elena Caneloi ◽  
Tatiane Gonçalves De Lima ◽  
Drielly Stefany Queiroz de Lucca

Connatural alterations can be deformations or malformations discovered in the embryonic development phase of the animal, which can disguise structures or roles of the systems. Congenital disorders can range from small changes, slight changes, serious adulterations and also genetic inconsistencies. There are no apparent defined reasons, and these changes may be caused by environmental and genetic factors. Pigopagus twins are joined at the back, have a coccyx, the gastrointestinal tract may have a single or separate rectum, a single bladder in some cases and obligatorily separate spinal cord and always with sharing of the pelvic bones. The ischiopagus are united by the ventral region from the navel to the pelvis, two sacrum and two pubic symphysis, in addition to a single gastrointestinal tract and a varied number of limbs. Reporting and discussing the morphological and anatomical deformities presented in a species of Squalus acanthias, recorded by LOPES in 2020, is a big step to better understand the anatomy and physiology of animals, which are considered the top of the food chain in the oceans and are in serious trouble. risk of extinction. RESUMO Alterações conaturais podem ser deformações ou más-formações descobertas na fase de desenvolvimento embrionário do animal, podendo disfarçar estruturas ou papéis dos sistemas. Os distúrbios congênitos podem ocorrer desde pequenas mudanças, alterações leves, adulterações sérias e também incoerências genéticas. Não existem motivos aparentes definidos, podendo estas alterações serem causados por fatores ambientais e genéticos. Os gêmeos Pigopagus são unidos pelo dorso, apresentam um coccix, o trato gastrointestinal pode apresentar reto único ou separado, bexiga única em alguns casos e obrigatoriamente medula espinhal separada e sempre com compartilhamento dos ossos pélvicos. Os isquiópagos apresentam-se unidos pela região ventral do umbigo à pelve, dois sacros e duas sínfises púpicas além de tratos gastrointestinal único e número de membros variados. Relatar e discutir as deformidades morfológicas e anatômicas apresentadas em uma especie de Squalus acanthias, registrada por LOPES em 2020, é um grande passo para entender melhor a anatomia e fisiologia de animais, que são considerados o topo da cadeia alimentar nos oceanos e correm um sério risco de extinção.  


Author(s):  
С. А. Царин

После длительного периода отсутствия ихтиологических исследований на научноисследовательских судах Института биологии южных морей имени А.О. Ковалевского в Чёрном море (за исключением ихтиопланктонных съемок и прибрежных ловов на фелюге) они были проведены в 68-м рейсе НИС «Профессор Водяницкий» осенью 2010 г. Особый интерес представляют ихтиологические наблюдения в районе ботанического заказника Филлофорного поля Зернова, где аналогичные работы не проводились уже несколько десятков лет. В исследованиях были использованы удебные ловы, визуальные наблюдения и случайные поимки рыб. Впервые в этом Филлофорном поле поймана присоска пятнистая Diplecogaster bimaculata (Bonnaterre, 1788) на столь далеком расстоянии от берега, но при этом на глубине обычной для обитания вида. По современном видовому составу рыб Филлофорное поле Зернова можно охарактеризовать как относительно бедный район северо-западной части Чёрного моря. Трофическая цепь рыб представлена следующим образом: шпрот Sprattus sprattus (Linnaeus, 1758)→мерланг Merlangius merlangus (Linnaeus, 1758)→катран Squalus acanthias Linnaeus, 1758. В ихтиоцен поля Зернова входят как стайные пелагические виды – ставрида Trachurus mediterraneus (Steindachner, 1868), шпрот, так и придонные – мерланг, присоска. По сборам в этом районе уточнены максимальные размеры самцов черноморского мерланга – 18,8 см в эконом зонах бывшего СССР. В районе Батилимана отмечена самая глубоководная поимка морского конька Hippocampus hippocampus (Linnaeus, 1758) в Чёрном море.


2021 ◽  
Vol 119 (1) ◽  
pp. 41-49
Author(s):  
Kelsey C. James ◽  
Lisa J. Natanson ◽  
Christopher Flight ◽  
Cindy Tribuzio ◽  
John Hoey ◽  
...  

2021 ◽  
Vol 72 (1) ◽  
pp. 131
Author(s):  
Romana Gracan ◽  
Bojan Lazar ◽  
Sara Zupan ◽  
Elena Bužan

Spiny dogfish Squalus acanthias is a widely distributed, highly migratory mesopredatory shark that is extremely sensitive to overexploitation. Because of unregulated targeted and incidental capture and a lack of enforceable management in the Mediterranean Sea, the spiny dogfish subpopulation has declined by at least 50% in the Mediterranean Sea over the past 75–105 years, and is regionally classified as endangered. In this study we sampled 124 spiny dogfish in the northern-most part of the Mediterranean (i.e. the Adriatic Sea) to: (1) assess levels of genetic diversity using 13 microsatellite loci and mitochondrial (mt)DNA (NADH dehydrogenase subunit 2 (ND2) gene); and (2) infer its evolutionary placement while assessing further possible genetic divergence across the Atlantic and Pacific Ocean basins based on ND2. Analysis of mtDNA revealed 12 unique haplotypes and a high level of genetic variation in the Mediterranean region, whereas results from microsatellite markers showed significant genetic heterogeneity and a fine-scale stock structuring involving both sexes. The findings support an Atlantic–South Pacific origin for the spiny dogfish in the Adriatic Sea, with little or no present-day connectivity with the Atlantic population. Consequently, this commercially exploited and regionally endangered coastal shark in the Adriatic Sea should be considered as a separate management unit, with implementation of regional protective management plans.


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