Gourt > Science > Environment > Biodiversity > Conservation > Fish > Sharks (2)
Sharks are a group (superorder Selachimorpha) of fish, with a full cartilaginous skeleton and a streamlined body, with normally 5, but up to 7 (depending on species) gill slits along the side of, or beginning slightly behind, the head (in some species, a modified slit called a spiracle, is located just behind the eye), dermal denticles covering the body to protect from damage, parasites and improve fluid dynamics, and rows of replaceable teeth in the mouth.
Characteristics
Sharks have keen olfactory senses, with some species able to detect as little as one part per million of blood in seawater. They are even more attracted to the chemicals found in the gut of many species, and often linger near or in sewage outfalls. Some species, such as nurse sharks, have external barbels that greatly increase their ability to sense prey. The short duct between the anterior and posterior nasal openings are not fused like in bony fish.
Shark eyes are similar to the eyes of other vertebrates, including similar lenses, corneas and retinas, though their eyesight is well adapted to their marine environment with the help of a tissue called tapetum lucidum. This tissue is behind the retina and reflects light back to the retina, thereby increasing visibility in the dark waters. The effectiveness of the tissue varies, with some sharks having stronger nocturnal adaptations. Sharks have eyelids, but they do not blink because the surrounding water cleans their eyes. To protect their eyes some have nictitating membranes. This membrane covers the eyes during predation, and when it is being attacked. However, some species, including the great white shark, Carcharodon carcharias do not have this membrane, but instead roll their eyes backwards to protect them.
More on [ Shark ]
Sharks :: Wildlife
Cartilaginous :: Fish
RT @SCUBA_RSS SCUBA NEWS - Just Released: Sharks of the World (source: Scuba Travel): This is billed as the first field guide to all http..
scuba_gear (Scuba Gear) Mon, 14 Dec 2009 08:11:42 -0000
RT @SCUBA_RSS SCUBA NEWS - Just Released: Sharks of the World (source: Scuba Travel): This is billed as the first field guide to all http..
Photo: Dany Heatley Atlanta Trashers Rookie Card. Cons about being up in SF. Heatley was in the Sharks store... http://tumblr.com/xuk4ogjd8
LeapsHigh (Nicole Alipio) Mon, 14 Dec 2009 08:11:14 -0000
Photo: Dany Heatley Atlanta Trashers Rookie Card. Cons about being up in SF. Heatley was in the Sharks store... http://tumblr.com/xuk4ogjd8
SCUBA NEWS - Just Released: Sharks of the World (source: Scuba Travel): This is billed as the first field guide to all http://url4.eu/vaPz
SCUBA_RSS (Scuba RSS) Mon, 14 Dec 2009 08:09:56 -0000
SCUBA NEWS - Just Released: Sharks of the World (source: Scuba Travel): This is billed as the first field guide to all http://url4.eu/vaPz
SCUBA NEWS - Just Released: Sharks of the World (source: Scuba Travel): This is billed as the first field guide to all http://url4.eu/vaPv
SCUBA_FEED (Scuba Feed) Mon, 14 Dec 2009 08:09:55 -0000
SCUBA NEWS - Just Released: Sharks of the World (source: Scuba Travel): This is billed as the first field guide to all http://url4.eu/vaPv
SCUBA NEWS - Just Released: Sharks of the World (source: Scuba Travel): This is billed as the first field guide to all http://url4.eu/vaPn
divezing (dive zing) Mon, 14 Dec 2009 08:09:53 -0000
SCUBA NEWS - Just Released: Sharks of the World (source: Scuba Travel): This is billed as the first field guide to all http://url4.eu/vaPn
Oshie, McDonald score in shootout, lift Blues to 3-2 victory over Sharks SAN JOSE, Calif. - T.J. Oshie had a..... http://bit.ly/7VfWS2
jeffreyzerr (Jeff Zerr) Mon, 14 Dec 2009 07:58:37 -0000
Oshie, McDonald score in shootout, lift Blues to 3-2 victory over Sharks SAN JOSE, Calif. - T.J. Oshie had a..... http://bit.ly/7VfWS2
BBC News: Increase in Shark Sightings - Article provides information on research from the Marine Conservation Society suggesting that basking shark populations may be beginning to recover in British waters.
Meta Description: [ A South West-based sailing boat helps with a database revealing an increase in sightings of basking sharks. ]
Bite-Back - Information about the species and the threats to their survival imposed by consumer demands. Discover news, information and links.
Meta Description: [ Shark Conservation campaign from Bite-Back - learn about endangered sharks and threatened fish species. Cutting-edge shark conservation and marine conservation projects to save sharks from overfishing and protect the oceans. ]
Conservation Pays Off - Article by Greg C. Bruno describes a commercial venture where tourists participate in a tag and release program off the coast of Cedar Key, Florida that has received praise from scientists.
European Basking Shark Identification Project (EBSPIP) - Project creating a catalog of digital identification images and their associated data. Features background, history, news, and contacts.
Meta Description: [ Information on Sharks, great white sharks, how to adopt a shark, the various types of sharks ]
Pelagic Shark Research Foundation - To help address the lack of data, and contribute to public awareness of the issues involved in shark conservation, the Pelagic Shark Research Foundation (PSRF) was formed as a nonprofit research and education group in 1990.
Meta Description: [ The Pelagic Shark Research Foundation (PSRF) Shark research, images, information. Since 1990. ]
Shark Conservation and Ecology Research - Information on DNA forensics and monitoring the fin trade from a project being conducted at the Guy Harvey Research Institute in Florida. Find information on current activities and how to participate in the research effort.
Meta Description: [ The Guy Harvey Research Institute conducts high quality, solution-oriented basic and applied
scientific research needed for effective conservation, restoration, enhancement, biodiversity maintenance and understanding of
the world's wild fish resources. GHRI also provides advanced training to US a... ]
Shark Foundation - International organization dedicated to the protection and preservation of endangered species. Find mission statement, information on lectures, tours and current research projects.
Meta Description: [ Shark Foundation - Foundation for research and the preservation of sharks ]
Shark Friends - Dedicated to dispelling myths about the species. Offers articles on finning, attacks and prevention, photos, and guestbook.
Meta Description: [ Sharks are fascinating creatures and this site hopes to dispel the myths and highlight the truths about them. Everything you ever wanted to know about sharks and info on other ocean animals too. ]
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Shark Specialist Group - Part of the Species Survival Commission of the IUCN. Article features group profile and photos.
Sharks - Details on the status, conservation, and management of sharks, in particular grey nurse and great white sharks, in Australian waters.
Meta Description: [ Sharks (elasmobranchs) comprise about 1% of all living fishes, and share nearly all the major features of their finned relatives. Like all fishes sharks use gills to extract oxygen from the water in which they live. ]
Sharktagger.com - Find information on the California Pelagic Shark Tagging Program. Features mission statement, message boards, image gallery, and studies.
Meta Description: [ This site is dedicated to Mako shark fishermen, shark tagging and shark conservation issues . ]
The IUCN/SSC Shark Specialist Group - Information about the species and the threats to shark populations. Features mission statement, newsletter, publications and contact details.
Meta Description: [ Florida Museum of Natural History Ichthyology Department homepage. This page contains, educational sections about the biology, ecology and conservation of fishes and sharks. A rich photo gallery features the work of world-renowned underwater photographers. Host for International Shark Attack File... ]
The Shark Trust - Organization dedicated to the conservation of species in general, including rays and skates. Find news, photos, information on joining and making donations.
Meta Description: [ Sharks, Information on Sharks, great white sharks, adopt a shark, types of sharks,shark finning ]
Watching Out for Sharks - Article describes the research and conservation efforts of the California Pelagic Shark Tagging Program. Includes a discussion of population status in California waters.
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