September 9th 2007
Posted under Wish I Shot That
September 6th 2007
Posted under News
Going on a road trip to the islands for a scuba expedition. Will be back on Monday!
It will be a well-earned break. You may have noticed that for the past week and a bit more, this website has been getting some really cool stories that other marine news sites never get. Or has been getting stories a lot earlier than other marine news sites.
It’s thanks to a new and highly refined news search pattern.
So you’re always sure of finding more cool stories and more unique stories right here. See you next week!
September 6th 2007
Posted under Science
Moray eels have a unique way of feeding reminiscent of a science fiction thriller, researchers at UC Davis have discovered. After seizing prey in its jaws, a second set of jaws located in the moray’s throat reaches forward into the mouth, grabs the food and carries it back to the esophagus for swallowing.
Rita Mehta, a postdoctoral researcher in the Section of Evolution and Ecology at UC Davis used a high-speed digital camera to film eels feeding in the laboratory, and was able to capture the rapid movement of these secondary pharyngeal jaws. She also used X-ray and other imaging equipment at the UC Davis School of Veterinary Medicine to work out how the jaws could move.
More than 200 species of moray eels are found in tropical waters worldwide, often living in holes in rocks and coral reefs. In the wild, they can reach 10 feet in length.
Most fish feed by suction. When it comes upon food or prey, the fish rapidly expands its mouth cavity, sucking in water and the food with it. Some fish feed by overtaking prey with their mouth open or grabbing it in their jaws, but most of those fish then use suction to move the food from the mouth to the esophagus.
But moray eels have little ability to generate suction through their mouths, Mehta found. Instead, they first grasp food with their powerful, toothsome outer jaws. Then the pharyngeal jaws, armed with large, curved teeth, reach forward and seize it. At the same time, the outer jaws release the prey and the pharyngeal jaws bring it back for swallowing. The whole process takes just fractions of a second.
Other fish are known to have pharyngeal jaws that can grind or crush food, but “nothing this spectacular,” said Peter Wainwright, professor of evolution and ecology at UC Davis and co-author with Mehta on the paper. Only the moray eel seems to have a second, mobile set of jaws that can reach forward and grab prey.
At rest, the pharyngeal jaws sit behind the eel’s skull. When they reach forward, they move almost the length of the animal’s skull, but do not protrude beyond the powerful outer jaws. The arrangement means that if the eel can sink in a few teeth to hold its prey, it can secure its meal with the pharyngeal jaws, the researchers note.
September 6th 2007
Posted under Conservation
A new study led by the University of Colorado at Boulder indicates biologists trying to save Colorado’s native greenback cutthroat trout from extinction over the past several decades through hatchery propagation and restocking efforts have, in most cases, inadvertently restored the wrong fish.
According to a sophisticated DNA analysis, five of nine “relic” populations of what biologists believed to be greenback cutthroat trout living in isolated pockets of the state actually are Colorado River cutthroat trout, a closely related subspecies, said lead author Jessica Metcalf, a researcher in CU-Boulder’s ecology and evolutionary biology department.
The new study, which included sequencing and analyzing mitochondrial and nuclear DNA, showed the majority of the greenback populations had been misidentified, and that the greenback cutthroat trout range is now restricted to just 11 miles of streams in several remote areas of Colorado.
The misidentification likely was caused by the stocking of fish in the late 1800s and early 1900s when railroads delivered hundreds of thousands of baby trout around the state of various species and subspecies for people to stock in local waters, said Metcalf.
Although greenback cutthroats were declared extinct in 1937 — victims of mining pollution, fishing pressure and competition from other trout species — several small populations were discovered in tributaries to the Arkansas River and South Platte River drainages in the 1950s, she said. Greenback cutthroats were added to the federal list of endangered species in 1978.
State and federal fish managers began taking eggs and sperm from what were believed to be surviving populations of pure greenback cutthroats in the 1970s, rearing them in hatcheries and returning them to native cutthroat habitat. The habitat — small streams and lakes — had been cleared of non-native fish species to heighten survivability of the greenbacks, said Metcalf.
September 6th 2007
Posted under Science
Now, two evolutionary biologists at the University of California, Berkeley, claim that, just as bats developed sonar to chase flying insects through the darkness, dolphins and other toothed whales also developed sonar to chase schools of squid swimming at night at the surface.
Because squid migrate to deeper, darker waters during the day, however, toothed whales eventually perfected an exquisite echolocation system that allows them to follow the squid down to that “refrigerator in the deep, where food is available day or night, 24/7,” said evolutionary biologist David Lindberg, UC Berkeley professor of integrative biology and coauthor of a new paper on the evolution of echolocation in toothed whales published online July 23 in advance of its publication in the European journal Lethaia.
“When the early toothed whales began to cross the open ocean, they found this incredibly rich source of food surfacing around them every night, bumping into them,” said Lindberg, former director and now a curator in UC Berkeley’s Museum of Paleontology. “This set the stage for the evolution of the more sophisticated biosonar system that their descendents use today to hunt squids at depth.”
Lindberg and coauthor Nick Pyenson, a graduate student in the UC Berkeley Department of Integrative Biology and at the Museum of Paleontology, reconstructed this scenario after looking at both whale evolution and the evolution of cephalopods like squid and nautiloids - relatives of today’s chambered nautilus - and relating this to the biology of living whales and cephalopods.
All toothed whales, or odontocetes, echolocate. The baleen whales, which sieve krill from the ocean and have no teeth, do not. The largest of the toothed whales, the sperm whale, grows up to 60 feet long and dives to 3,000 meters - nearly two miles - in search of squid. Though poorly known because they live entirely in the deep ocean, the many species of the beaked whale dive nearly as deep. Belugas and narwhals descend beyond 1,000 meters, while members of the dolphin family - porpoises, killer whales and pilot whales, for example - all can dive below the 200-meter mark where sunlight is reduced to darkness.
According to Pyenson, who focuses on the evolution of whales, the first whales entered the ocean from land about 45 million years ago, and apparently did not echolocate. Their fossil skeletons do not have the scooped forehead of today’s echolocating whales, which cups a fatty melon-shaped ball that is thought to act as a lens to focus clicking noises.
Skulls with the first hints of a concave forehead and potential sound-generating bone structures arose about 32 million years ago, Pyenson said, by which time whales presumably had spread throughout the oceans. Whales had developed underwater hearing by about 40 million years ago.
September 6th 2007
Posted under Wish I Shot That
Vidar.a caught this jellyfish with a Canon Powershot G7, 1/60@f4. Wish I shot that!
September 5th 2007
Posted under Conservation
When a Coney Island lifeguard spied a shark near an upset group of swimmers, he did what he thought was right: He rescued the fish.Marisu Mironescu, 39, said he was prompted to action Monday after seeing about 75 to 100 people circling the 2-foot sand shark off the beach and “bugging out.” “They were holding onto it and some people were actually hitting him, smacking his face,” said Mironescu. “Well, I wasn’t going to let them hurt the poor thing.”
He grabbed the largely harmless shark in his arms and carried it, backstroking out to sea, where he let it go. “He was making believe like he’s dead, then he wriggled his whole body and tried to bite me,” Mironescu said.
“We had a little bit of a punctuation mark at the end of summer with ‘Jaws’ junior showing up and frightening people,” said Adrian Benepe, the city Parks Commissioner.
The rescue ended a holiday weekend that began with another city shark scare Saturday, when a 5-foot thresher shark washed up on Rockaway Beach, sending hundreds of swimmers out of the water. About 10 blocks of the beach were also closed down for hours on Labor Day weekend.
September 5th 2007
Posted under Science
The shark’s ability to inflict killer damage on anything it grabs, however, probably is due to saw-like teeth and not the amount of bite force, researchers say. Once a great white clamps down on a prey with its razor-sharp teeth, the shark often shakes the catch from side to side to initiate a sawing action.
Daniel Huber, a biologist at the University of Tampa in Florida, examined an eight-foot (2.4-meter) great white shark that had died after becoming entangled in nets off the coast of Australia. Huber and his colleagues dissected the shark’s head and took several measurements, including the size and placement of the jaw muscles.
“We are figuring out in three dimensions the leverage of all of these jaw muscles,” Huber told LiveScience. The jaws work like a set of pliers, where pliers with long handles would let you grab an item with more force than pliers with short handles.
From this data, the researchers are developing a 3-D digital recreation of the shark and a computer simulation of a full-force bite. They will compare the final force estimate with those from tiger and bull sharks, which, along with the great white, are responsible for most shark attacks on humans.
“The white has the narrowest head of the three, so it has less space for jaw muscles,” Huber said. “Consequently, we’re expecting that it will have a lower bite force on a pound-for-pound basis.”
But great whites would still top the charts as savviest hunters and most adept at capturing prey. “Much of the damage inflicted by white sharks is due to their teeth, and not necessarily to the force,” Huber said.
September 5th 2007
Posted under News
The Fiji Fisheries Department has allowed turtle meat to be part of the delicacies offered during the Methodist Church of Fiji’s annual conference beginning on Tuesday. The Fijilive website reports that this is despite turtles being on a list of protected species.
The Director of Fisheries Sainaila Nagali says his office has received three separate requests from some members of the Methodist Church in the province seeking to harvest about several turtles for feasting during the 3-day conference.
Mr Nagali says he has taken the protected status of the turtles into account and has recommended to the Fisheries Permanent Secretary to allow the fishing for just one turtle for each application.
September 5th 2007
Posted under Wish I Shot That
Tukhar caught these jellyfish in motion with a Canon Powershot G3 and without a flash using 1/50@f2.2. Wish I shot that!
