LSM4261 MARINE BIOLOGY : nekton

"Sharks are masters of seven senses"

N. Sivasothi — Wed, 06 Feb 2008 15:18:24 GMT

"Sharks are masters of seven senses" (Shark Foundation webpage).

Sharks "see in the dark better than cats, they smell 10,000 times better than humans and have a highly developed sense of taste. They have excellent hearing, receive and sense even the slightest differences in pressure, feel currents and can detect the electrical fields of their prey."

For a quick overview read on...

TED Talks: Tierney Thys: Swim with giant sunfish in the open ocean

N. Sivasothi — Wed, 06 Feb 2008 14:47:46 GMT

An excellent lecture that the class watched today. See also oceansunfish.org.

Fish swimming modes

N. Sivasothi — Wed, 06 Feb 2008 14:35:34 GMT

An overview of the swimming mechanisms employed by fish is provide by Sfakiotakis, M., D. M. Lane, J. Bruce & C. Davies, 1999. Review of Fish Swimming Modes for Aquatic Locomotion. IEEE J. Oceanic Engineering, 24(2): 237 - 252.

'Fish swim either by body and/or caudal fin (BCF) movements (for greater thrust and acceleration) or by using median and/or paired fin (MPF) propulsion; the latter generally employed at slow speeds, offering greater maneuverability and better propulsive efficiency.'

First video of a live giant squid (Architeuthis dux) (2006)

N. Sivasothi — Wed, 06 Feb 2008 14:22:43 GMT

Nippon TV News clip on You Tube

National Geographic News, 22 Dec 2006 — Like pulling a shadow from the darkness, researchers in Japan have captured and filmed a live giant squid—likely for the first time—shedding new light on the famously elusive creatures.

Tsunemi Kubodera, a scientist with Japan's National Science Museum, caught the 24-foot (7-meter) animal earlier this month near the island of Chichijima, some 600 miles (960 kilometers) southeast of Tokyo. His team snared the animal using a line baited with small squid and shot video of the russet-colored giant as it was hauled to the surface.

The squid, a young female, "put up quite a fight" as the team attempted to bring it aboard, Kudobera told the Associated Press, and the animal died from injuries sustained during the capture.

Giant squid, the world's largest invertebrates, are thought to reach sizes up to 60 feet (18 meters), but because they live at such great ocean depths they have never been studied in the wild. Kubodera has spent three years searching for the creatures, and his team scored a coup in 2004 when it used a remote underwater camera to take the first-ever photographs of a live giant squid.

The capture may be a sign that giant squid are more plentiful than had been thought, Kubodera said, and the event could help open up more fruitful research into the poorly understood animal. "Now that we know where to find them, we think we can be more successful at studying them in the future," he said. —Blake de Pastino

See also National Geographic Fast Facts: Giant Squid (Architeuthis dux).

The skeletal material of choice for the ocean's giant fishes

N. Sivasothi — Wed, 06 Feb 2008 09:14:00 GMT

In "No Bones About ’Em," Adam Summers asks "why did the ancestors of today’s sharks and other cartilaginous fishes abandon bone in favor of a skeletal material that other large animals use only sparingly? I have recently come to think that cartilage gives sharks at least one important selective advantage: they can grow much bigger than bony fishes."

See "No Bones About ’Em," by Adam Summers with illustrations by Tom Moore. Natural History Magazine, March 2007.