Great White Sharks tagged for first time off Massachusetts

Massachusetts officials are using high-tech tags to track the movements of two great white sharks near Cape Cod — the first time the fearsome fish have ever been tagged in the Atlantic Ocean.The electronic tag uses satellite technology to record the travels of the sharks, allowing scientists to better understand their migratory patterns.The sharks were spotted Saturday by scientists investigating sightings off Monomoy Island in Chatham. Officials say a harpooner tagged them with help from a state shark expert.Sharks are common in Cape waters during summer, though great white sharks are relatively rare around New England.State officials have warned area swimmers to be on the lookout for sharks this weekend, and state environmental police are patrolling the area as a precaution.

Millions of fish shoal in seconds

A 'critical threshold' causes the fish to form shoals covering many kilometres Researchers in the US have recorded the point at which hundreds of millions of herring coalesce into a vast shoal. The team used equipment, which they also invented, that uses sound waves to remotely monitor movement of the fish. They found that, when the herring numbers reach a tipping point, or "critical threshold", this triggers a chain reaction whereby the shoal forms within seconds. The findings are reported in the journal Science. Herring form shoals to migrate during the autumn spawning season. The shoal moves in a "highly organised fashion" and hundreds of millions of herring travel together to shallower waters to spawn. The very ordered movement of the fish has reinforced an earlier theory that very large groups of migrating animals - swarms or shoals - act as one. Fibre optic ocean The technology the researchers used is called Ocean Acoustic Waveguide Remote Sensing. This produces an image of the whole shoal by bouncing sound waves off the bodies of the fish. With this equipment, measurements could be taken at such a high speed that the team was able to create a moving image of the forming shoal. Using sound waves to monitor animals in the darkness of the ocean is not new. But traditionally, a single survey vessel sends high-frequency sound beams into the ocean - taking a snapshot of a relatively small area. The new system uses much lower frequency sound that can travel much farther. The fish form a shoal covering tens of kilometres within tens of minutes Nicholas Makris MIT "It's like using the ocean as a fibre optic cable," explained Nicholas Makris, the Massachusetts Institute of Technology (MIT) professor who led the research. "The low frequency beams stay trapped in the water column and can cover a 100km area in a minute and a half." This, says Professor Makris, is a vast improvement over conventional techniques, which Makris compared to "watching one pixel on a movie screen" while the new technology allows you to "see the entire movie." 'Cities of fish' The herring's initial movement seems to be triggered by the reduction in light as the sun sets. "When the light fades, it's safer for the fish to move away from the seabed," says Professor Makris. "Once they have a certain number of other fish in their sphere of perception, they suddenly come together - forming a shoal covering tens of kilometres within tens of minutes." The herring gather in such huge numbers, and under cover of darkness, for "synchronised spawning". This helps protect them from predators. The ordered movement of the shoal means the fish can reach their spawning ground more quickly and more safely. "This is truly a commute," says Professor Makris. "And there are truly cities of fish down there." BBC News

Researchers Tag First-ever Free-swimming Leatherback Turtles In New England

University of New Hampshire researchers have tagged one male and two female leatherback turtles off Cape Cod. They are the first free-swimming leatherbacks ever tagged in New England.The 700 - 800-pound leatherback turtles, an endangered species, were tagged July 17, 26 and 29 with GPS-linked satellite tags that transmit nearly real-time tracking data, allowing scientists to better understand these elusive, highly migratory giants to enhance their survivability."We investigators spent 20 years attempting to learn about these animals on the high seas and temperate ocean waters, with only slow progress," says UNH research associate professor Molly Lutcavage, director of UNH's Large Pelagics Research Center. "This work will be useful for marine resource managers and others who want to understand how leatherbacks spend their days in the New England region and beyond." Lutcavage notes that this year's success is due to a convergence of people, know-how, and funding that allows researchers access to resources like spotter planes and commercial fishermen.And, says Kara Dodge, the UNH Ph.D. student leading the tagging effort, the turtles are cooperating. "It's leatherback craziness this year," she says, noting that warmer water temperatures have brought an abundance of jellyfish, the primary food source for leatherbacks.The $5,000 GPS-linked satellite tags Dodge and her colleagues, including Andy Myers, a postdoctoral researcher in the Large Pelagics Research Center (LPRC), are attaching to the leatherbacks aim to fill the knowledge gap on these elusive swimmers. The tags transmit depth, water temperature and location information daily via satellite, allowing researchers to gain much-needed insight into the movement patterns of the sea turtles. Dodge is also analyzing the data as it relates to oceanographic conditions and jellyfish distribution. The LPRC tagging team has been joined by investigators from the New England Aquarium's rescue rehab group and the Provincetown Center for Coastal Studies, who are profiling leatherback health and clinical information.Dodge has tracked the male, who was tagged July 17 about eight miles offshore in Nantucket Sound, to south of an area called the Canyons, off the continental shelf. He has traveled about 1100 kilometers in less than two weeks. "He just took off," she says. "I think it's a speed record." The females, tagged July 26 and 29 in Vineyard Sound just eight miles southwest of Woods Hole, are swimming at a more leisurely pace; the first female is about 250 kilometers from where she was tagged and the second female swam about 65 kilometers between Tuesday and Wednesday.Leatherback turtles, which can weigh up to 2000 pounds and are warm-bodied, like bluefin tuna, are the largest living reptiles in the world. The most migratory sea turtle species, they travel great distances through a wide range of water temperatures and to great depths. In the western Atlantic, leatherbacks travel from their nesting grounds in the Caribbean, northern South America, and southeast Florida to the productive foraging ground of Atlantic Canada. Leatherbacks typically come to the waters off Cape Cod from July through October although, says Dodge, "we've never known whether they're coming to forage or just passing through."Previous tagging efforts by Dodge, Myers and Lutcavage have focused on leatherbacks that have been entangled in buoy lines of fishing gear. This year, thanks to additional funding from the National Fish and Wildlife Foundation, the researchers have been able to take commercial lobster boats out to areas where leatherbacks have been spotted. This off-shore access allowed Dodge to put a tag on a male; because they never return to shore after they hatch, little is known about male leatherbacks.Off shore and away from their nesting areas, leatherback turtles have no natural predators except sharks and killer whales; entanglement in fishing gear, ingestion of marine debris and injuries from boat propellers are the major threats to their survival. "Understanding where they travel and how they use the water column will help us mitigate these human interactions," says Dodge. Emerging research indicates that climate change likely has a large impact on the leatherback population, as well.Lutcavage, who's been working to better understand New England leatherback turtles since 1993, is thrilled to see the years of planning come to fruition. "It's been a long wait," she says.The tagging effort will continue off Cape Cod through September; Dodge hopes to tag nine more leatherbacks. In addition to the National Fish and Wildlife Foundation, this work is supported by the National Marine Fisheries Service Northeast Regional Office and the Cape Cod Commercial Hook Fishermen's Association."Henry," the first free-swimming leatherback captured in New England waters, was tagged with a GPS-linked satellite tag by researchers from the University of New Hampshire's Large Pelagics Research Center. (Credit: Connie Merigo, New England Aquarium)Source: University of New Hampshire.

Fish tag flies from Oregon to New Zealand

A small electronic tag that was implanted in a Steelhead Salmon Oncorhynchus mykiss at the USFWS Columbia River Hatchery (USA) has been discovered in New Zealand. Because Steelhead Salmon do not migrate across the equator, the best theories about the [UTF-8?]tag’s travels involves Sooty Shearwaters Pufinus griseus.The tiny device was noticed by Maori hunter Dale Whaitiri on Mokonui Island, one of the Titi Islands (New Zealand). Shearwaters nest in burrows among tree roots on the island, and are known locally as Titi or Muttonbirds. The tag was recorded two years earlier as young steelhead smolts were passing the Bonneville Dam, on the Columbia River [UTF-8?]– 10,170 km from Mokonui!