نتایج جستجو برای: sharks

تعداد نتایج: 2511  

Journal: :Journal of experimental marine biology and ecology 2000
Sims

Movements of six basking sharks (4.0-6.5 m total body length, L(T)) swimming at the surface were tracked and horizontal velocities determined. Sharks were tracked for between 1.8 and 55 min with between 4 and 21 mean speed determinations per shark track. The mean filter-feeding swimming speed was 0.85 m s(-1) (+/-0.05 S.E., n=49 determinations) compared to the non-feeding (cruising) mean speed ...

2017
Lucy A. Howey Bradley M. Wetherbee Emily R. Tolentino Mahmood S. Shivji

BACKGROUND Blue sharks (Prionace glauca) are among the most abundant and widely distributed of oceanic elasmobranchs. Millions are taken annually in pelagic longline fisheries and comprise the highest component of auctioned fin weight in the international shark fin trade. Though studies of blue sharks outnumber those of other large pelagic sharks, the species' complicated and sexually segregate...

2014
Candice Chi-Hang Cheung Richard K. Larson R. K. Larson

Psych verb constructions show peculiar properties. They appear to project the same θ -relations into inverse configurations (John fears sharks/Sharks frighten John). Furthermore, Experiencer Object psych verb constructions admit backward binding in apparent violation of familiar c-command conditions (Pictures of himself anger John). We offer a solution to both puzzles drawing crucially on data ...

2013
I.J.M. van Beek A. O. Debrot M. de Graaf

In the Dutch Caribbean EEZ, at least 27 elasmobranch species have been documented. Of these, nine are listed as “critically endangered” and eight as “near threatened” by the IUCN. Elasmobranchs are not a target fishery in the Dutch Caribbean, but do occur as bycatch in artisanal fisheries. Sharks are considered nuisance species by fishermen. Most sharks caught are not discarded, but consumed lo...

2015
John P. Tyminski Rafael de la Parra-Venegas Jaime González Cano Robert E. Hueter Shing Yip Lee

The whale shark (Rhincodon typus) is a wide-ranging, filter-feeding species typically observed at or near the surface. This shark's sub-surface habits and behaviors have only begun to be revealed in recent years through the use of archival and satellite tagging technology. We attached pop-up satellite archival transmitting tags to 35 whale sharks in the southeastern Gulf of Mexico off the Yucat...

2015
Itsumi Nakamura Carl G. Meyer Katsufumi Sato David Mark Bailey

We do not expect non air-breathing aquatic animals to exhibit positive buoyancy. Sharks, for example, rely on oil-filled livers instead of gas-filled swim bladders to increase their buoyancy, but are nonetheless ubiquitously regarded as either negatively or neutrally buoyant. Deep-sea sharks have particularly large, oil-filled livers, and are believed to be neutrally buoyant in their natural ha...

2016
Nicholas L. Payne Gil Iosilevskii Adam Barnett Chris Fischer Rachel T. Graham Adrian C. Gleiss Yuuki Y. Watanabe

Animals exhibit various physiological and behavioural strategies for minimizing travel costs. Fins of aquatic animals play key roles in efficient travel and, for sharks, the functions of dorsal and pectoral fins are considered well divided: the former assists propulsion and generates lateral hydrodynamic forces during turns and the latter generates vertical forces that offset sharks' negative b...

2008
David W. Sims

There is now a general agreement that sharks, and pelagic sharks in particular, are facing widespread declines in population level due to fishing activity (Pauly et al., 2003). Recent studies suggest dramatic reductions in relative abundance of up to 80% have occurred in as little as 15 years for some species (Baum et al., 2003; Myers et al., 2006), trends most likely linked to greater target c...

2016
Kazuhiro Nakaya Taketeru Tomita Kenta Suda Keiichi Sato Keisuke Ogimoto Anthony Chappell Toshihiko Sato Katsuhiko Takano Yoshio Yuki

Five striking and prey capture events of two goblin sharks were videotaped at sea for the first time, showing their extraordinary biting process. The goblin sharks swung their lower jaw downward and backward to attain a huge gape and then rapidly protruded the jaws forward a considerable distance. The jaws were projected at a maximum velocity of 3.1 m/s to 8.6-9.4% of the total length of the sh...

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