نتایج جستجو برای: sharks

تعداد نتایج: 2511  

Journal: :Environmental pollution 2014
Zhe Lu Aaron T Fisk Kit M Kovacs Christian Lydersen Melissa A McKinney Gregg T Tomy Bruno Rosenburg Bailey C McMeans Derek C G Muir Charles S Wong

Polychlorinated biphenyls (PCBs) chiral signatures were measured in Greenland sharks (Somniosus microcephalus) and their potential prey in arctic marine food webs from Canada (Cumberland Sound) and Europe (Svalbard) to assess temporal and spatial variation in PCB contamination at the stereoisomer level. Marine mammals had species-specific enantiomer fractions (EFs), likely due to a combination ...

2015
Anna Schleimer Gonzalo Araujo Luke Penketh Anna Heath Emer McCoy Jessica Labaja Anna Lucey Alessandro Ponzo Donald Kramer

While shark-based tourism is a rapidly growing global industry, there is ongoing controversy about the effects of provisioning on the target species. This study investigated the effect of feeding on whale sharks (Rhincodon typus) at a provisioning site in Oslob, Cebu, in terms of arrival time, avoidance and feeding behaviour using photo-identification and focal follows. Additionally, compliance...

2014
Carl G. Meyer Joseph M. O'Malley Yannis P. Papastamatiou Jonathan J. Dale Melanie R. Hutchinson James M. Anderson Mark A. Royer Kim N. Holland

Tiger sharks (Galecerdo cuvier) are apex predators characterized by their broad diet, large size and rapid growth. Tiger shark maximum size is typically between 380 & 450 cm Total Length (TL), with a few individuals reaching 550 cm TL, but the maximum size of tiger sharks in Hawaii waters remains uncertain. A previous study suggested tiger sharks grow rather slowly in Hawaii compared to other r...

2016
Stephen M. Kajiura Shari L. Tellman

Southeast Florida witnesses an enormous seasonal influx of upper trophic level marine predators each year as massive aggregations of migrating blacktip sharks (Carcharhinus limbatus) overwinter in nearshore waters. The narrow shelf and close proximity of the Gulf Stream current to the Palm Beach County shoreline drive tens of thousands of sharks to the shallow, coastal environment. This natural...

Journal: :PLoS ONE 2008
Sébastien Trape

BACKGROUND The International Shark Attack File mentions only four unprovoked shark attacks on the coast of West Africa during the period 1828-2004, an area where high concentrations of sharks and 17 species potentially dangerous to man have been observed. To investigate if the frequency of shark attacks could be really low and not just under-reported and whether there are potentially sharks tha...

2015
Robert P. French Jeremy Lyle Sean Tracey Suzanne Currie Jayson M. Semmens

The shortfin mako shark (Isurus oxyrinchus) is a species commonly targeted by commercial and recreational anglers in many parts of the developed world. In Australia, the species is targeted by recreational anglers only, under the assumption that most of the sharks are released and populations remain minimally impacted. If released sharks do not survive, the current management strategy will need...

Journal: :Science 1912

Journal: :Marine environmental research 2013
Kady Lyons Aaron Carlisle Antonella Preti Christopher Mull Mary Blasius John O'Sullivan Chuck Winkler Christopher G Lowe

Organic contaminant and total mercury concentrations were compared in four species of lamniform sharks over several age classes to examine bioaccumulation patterns and gain insights into trophic ecology. Contaminants found in young of the year (YOY) sharks were assumed to be derived from maternal sources and used as a proxy to investigate factors that influence maternal offloading processes. YO...

Journal: :Marine pollution bulletin 2015
Kady Lyons Christopher G Lowe

Pacific angel sharks (Squatina californica) are a benthic elasmobranch that occupy intermediate trophic level positions in coastal food webs. Angel sharks' life history characteristics make them susceptible to accumulating high amounts of contaminants. Four angel sharks were opportunistically captured in southern California and their liver and uterine contents were analyzed for PCBs, DDTs and o...

Journal: :Marine pollution bulletin 2017
Adam G Matulik David W Kerstetter Neil Hammerschlag Timothy Divoll Chad R Hammerschmidt David C Evers

Mercury bioaccumulation is frequently observed in marine ecosystems, often with stronger effects at higher trophic levels. We compared total mercury (THg) and methylmercury (MeHg) from muscle with length, comparative isotopic niche, and diet (via δ13C and δ15N) among four sympatric coastal sharks in Florida Bay (USA): blacknose, blacktip, bull, and lemon. Mercury in blacknose and blacktip shark...

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