SAVING SHARKS WITH MAGNETS
Michael Herrmann, a research associate at the US-based company Shark Defense, has won the 2006 World Wildlife Fund-sponsored Smart Gear competition for an innovation that addresses the problem of shark bycatch. Knowing that sharks can detect magnetic fields, Herrmann found that placing strong magnets just above the hooks on longline fishing gear can repel certain shark species. Every year thousands of sharks die after becoming snared on hooks set by commercial fisheries to catch fish such as tuna and swordfish. The problem has pushed some shark species to the brink of extinction, with some populations down by 90 per cent. Herrmann will receive the US$25,000 grand prize to further develop and test his winning idea.

Source: World Wildlife Fund, 11 May 2006
http://www.panda.org/news_facts/newsroom/index.cfm?uNewsID=68540

DOLPHINS NAME THEMSELVES WITH SIGNATURE WHISTLES
Some bottlenose dolphin whistles appear to communicate the caller's individual "name" information, which other dolphins can recognize even when the caller's voice features are electronically removed, Scottish and U.S. researchers report. As infants, bottlenose dolphins develop their own signature whistles to use throughout their lifetimes. Signature whistles are individually distinctive signals given by the dolphins. Members of dolphin groups repeat these whistles back during vocal interactions, and researchers have found that the whistles form a system similar to that of human naming. The study's lead author, Dr. Vincent Janik from the University of St. Andrews and his colleagues, studied a group of bottlenose dolphins in Sarasota Bay, Florida, to investigate whether individual discrimination through signature whistles is independent of voice features, as it is in human naming. This study will be reported in an upcoming issue of Proceedings of the National Academy of Sciences

Source: Environmental New Service 9 May 2006
http://www.ens-newswire.com/ens/may2006/2006-05-09-02.asp

Scientists Uncover New Clues to Limb Formation (and Loss) in Some Sea Mammals

Findings help solve mystery of whales' missing legs

Researchers from the Northeastern Ohio Universities College of Medicine have revealed the genetic basis behind one of the best-documented examples of evolutionary change in the fossil record: how whales lost their hind limbs.

Small blue bars beneath the tails indicate a pelvis that once supported hind legs.

Writing in this week's Proceedings of the National Academy of Sciences (PNAS), Hans Thewissen and his colleagues report that ancient whales--four-footed land animals not unlike large modern dogs--evolved into graceful, streamlined swimmers through a series of small genetic changes during the whales' embryonic development.

"Their research has implications for how evolution acts to create dramatic changes in an organism's body," said Richard Lane, program director in the National Science Foundation (NSF)'s Division of Earth Sciences, which funded the research.

"The findings emphasize the synergistic role traditional paleontology and evolutionary and developmental biology play at the frontiers of the evolutionary sciences," said Lane.

Thewissen and his colleagues began by exploring the embryonic development of whales' cousins, the dolphins. These creatures are intriguing because for a brief time during development they do sprout hind limbs, which quickly vanish again as the embryos reach the second month in a gestation period that lasts about 12 months.

Why? In most mammals, explains Thewissen, "a series of genes is at work at different times, delicately interacting to form a limb with muscles, bones, and skin. The genes are similar to the runners in a complex relay race, where a new runner cannot start without receiving a sign from a previous runner."

In dolphins, however, at least one of the genes drops out early in the race, disrupting the genes that were about to follow it. That causes the entire relay to collapse, ultimately leading to the regression of the animals' hind limbs. By analyzing dolphin embryos, Thewissen showed that the dropout is a gene called "Sonic Hedgehog," which is important at several stages of limb formation.

"That's why dolphins lose their 'legs,'" he says.

In whales, however, the story is more complex. Between 41 million and 50 million years ago, whales' hind limbs did shrink greatly as the former land animals began a return to the sea. But their legs showed no change in the basic arrangement and number of bones, which proved that Sonic Hedgehog was still functioning. Its loss must have come later.

In short, "the dramatic loss of Sonic Hedgehog expression was not the genetic change that drove hind limb loss in whales," Lane said.

Instead, Thewissen and his colleagues conclude, whales' hind limbs regressed over millions of years via "Darwinian microevolution": a step-by-step process occurring through small changes in a number of genes relatively late in development.

-NSF-

Swimming Robot Tests Theories About Locomotion in Existing and Extinct Animals

May explain why four-flippered swimmers now use only two

An underwater robot is helping scientists understand why four-flippered animals such as penguins, sea turtles and seals use only two of their limbs for propulsion, whereas their long-extinct ancestors seemed to have used all four.

Madeleine is helping scientists and engineers better understand how flippered animals swim.

When researchers put a joystick-controlled robot named Madeleine through her paces, they found that her top cruising speed did not increase when she used four flippers instead of two--apparently because the front flippers created turbulence that interfered with the rear flippers' ability to generate forward propulsion. Maintaining the same speed with four flippers also took significantly more energy. But Madeleine was able to make quicker starts and stops with all four.

Results from experiments such as these aid engineers in designing underwater autonomous vehicles and help scientists understand why certain traits survived over others during the process of evolution.

Scientists who study fossils of four-limbed aquatic dinosaurs, such as plesiosaurs, say the shape and musculature of their appendages suggests they used all of their flippers for locomotion. But over time, the benefits of two-flippered swimming won out. Extrapolating from experiments with Madeleine, scientists hypothesize that plesiosaurs benefited from using all fours to ambush prey.

Madeleine was developed by Vassar College's John Long and his colleagues at Nekton Research, LLC (Durham, N.C.) through support provided by the National Science Foundation's (NSF) Collaborative Research at Undergraduate Institutions program and the Major Research Instrumentation program.

--Randy Vines

Investigators
John Long

Georgetown Blue Marlin tournament hosts second leg of billfishing series

Forty-eight boats braved the weather during the second tournament in the 18th season of the South Carolina Governor’s Cup Billfishing Series, the Georgetown Blue Marlin Tournament, when it was held May 17-20 at the Georgetown Landing Marina.

The Governor’s Cup Billfishing Series features five tournaments along the coast that began May 3 at Edisto Island and ends July 1 at the Charleston City Marina’s HMY/Viking MegaDock Billfishing Tournament.

"The weather was dicey at best," said Tom DuPré, Billfishing Series coordinator with the S.C. Department of Natural Resources (DNR). "Reports concerning the height of the seas were directly proportional to the size of the boat. The wind and rain did their best to dampen the festivities, but were not up to the task for this crowd in Georgetown."

Over the course of the weekend, a total of six blue marlin were released, one blue marlin was tagged, three white marlin were released, one sailfish was tagged and one sailfish was released. Forty-eight boats entered the 39th Annual Georgetown Blue Marlin Tournament.

"Thanks to a great staff at the Georgetown Landing Marina, the tournament went as smoothly as in any memory," said DuPré. "Marina manager Rick Ferdon was presented a plaque by co-workers and friends as a token of appreciation for his 20 years of service to the tournament. Next year will be the 40th year for this Georgetown tournament, and they say it will be the best yet."

Points for Governor's Cup tournaments are awarded as follows: 300 points for a tagged or released blue marlin, 150 points for a tagged or released white marlin, and 100 points for a tagged or released sailfish. In addition, boats are awarded 25 participation points for each Series tournament entered up to a maximum of three events.

"Blue Boy," owned by Douglas Heaton of Charleston, won the Best Billfish Boat and raked in 600 points for catching and releasing two blue marlin.Finishing in second place at the Georgetown Blue Marlin Tournament was "Syked Out," owned by David Sykes of Isle of Palms. He amassed 500 points for a blue marlin released and two sailfish released. "Syked Out" also won the Conservation Award for their release of three billfish during the tournament weekend.

Third-place honors for Best Billfish Boat went to "Sportin’ Life," owned by Manly Eubank of Charleston. "Sportin’ Life" earned 450 points for catching and releasing a blue marlin and a white marlin.

Ed Renken of Mt. Pleasant caught a 49.9-pound wahoo to earn the Largest Wahoo Award aboard his boat "Sea Fox."

The Largest Dolphin Award went to Chris Tucker of Blythewood, on "Bakbar," owned by Bakbar Marine Group of Mt.Pleasant. He reeled in a 59.6-pound dolphin.

A 54.7-pound yellowfin tuna caught aboard "Hattitude" earned owner and angler Steve Chryst of Myrtle Beach the Largest Tuna Award.

The Outstanding Female Angler Award went to Holly McAlhany of Wando, on "Syked Out," owned by David Sykes of Isle of Palms, for catching and releasing a blue marlin.

Quinn Johnson from Beaufort, won second-place honors for the Outstanding Female Angler Award for landing a 35.9-pound wahoo, a 24.3-pound dolphin, and a 9.4-pound skipjack tuna onboard "My Time Out," owned by Frank Gibson of Beaufort.

Third-place honors for the Outstanding Female Angler Award went to Libby Kosnik of Columbus, Ohio, for landing a 30.2-pound dolphin on "Special Lady," owned by Ed Kosnik.

Jacob Henderson, 13, of Spartanburg won the first place Youth Angler Award for landing a 49.9-pound yellowfin tuna and an 8.3-pound dolphin on "Pace Maker," owned by Last Hurrah LLC of Wilmington, Del.

Brandon Mitchell, 15, of Stanley, N.C., landed a 22.9-pound wahoo and a 22.3-pound dolphin to win the second place Youth Angler Award on "Trophy Hunter," owned by Mark Mitchell of Charlotte.

Al DeLeon, 14, of Mt.Pleasant landed a 20.9-pound dolphin on "Emotional Rescue," owned by Michael DeLeon, also of Mt.Pleasant, to win third place honors for the Youth Angler Award.

Only one blue marlin was landed during the 39th Annual Georgetown Blue Marlin Tournament. Angler and owner Greg Smith of Anderson, onboard his "Blue Sky" landed a 420.6-pound blue marlin.

Overall standings for the 18th Annual South Carolina Governor’s Cup Billfishing Series after the second tournament and with three remaining tournaments are as follows: "Blue Boy," 625 points; "Syked Out," 525 points; "Sportin’ Life," 500 points; "Blue Sky," 470.6 points; and "Cookie Monster," 350 points.

Remaining tournament dates and contacts for the upcoming 2006 18th Annual South Carolina Governor's Cup Billfishing Series are:

Boats participating in the Governor’s Cup Billfishing Series amass points for billfish either landed, tagged, or released. Anglers compete for four major awards: Outstanding Billfish (single heaviest billfish), Outstanding Billfish Boat (most accumulated points) and Outstanding Billfish Conservationist (most points for tagged or released fish), and the Blue Water Conservation Award (most accumulated tag and release points for dolphin, wahoo, and yellowfin tuna).

By encouraging live tag and release, the Billfishing Series has focused attention on the sharp decline of Atlantic billfish and encouraged conservation of all marine resources.