Guy Harvey Magazine

WIN 2012

Guy Harvey Magazine is focused on fishing, boating, scuba diving, and marine conservation. Portfolios from the world's best fishing photographers, articles on gear, travel, tournaments, apparel, lifestyle, seafood recipes, sustainable fisheries.

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Page 46 of 83

Understanding the big picture of how species integrate and migrate along the Pacific coast is critical to maintaining healthy fisheries. places where things are happening, not just swirling around in an eddy." Virtually all of the tags, varying from $1,500 to more than $8,000, included a sensor for depth and temperature; many had sensors for light to help locate the animal when satellite connections were not possible. Because of the detailed data, TOPP team members were able to link north/ south seasonal migration of tunas, sharks, and blue whales along the southern U.S. coast with seasonal changes in water temperature and chlorophyll concentrations. (High chlorophyll levels indicate a high level of plankton in the water, which in turn correlates to concentrations of fish that are a food source for larger predators.) The correlation is so strong that, now that scientists are aware of the pattern, they can predict a species' location using satellite observations of temperature and chlorophyll changes. "This is fundamental to the concept of ecosystem-based management," says Dr. Costa. The data also revealed that animals and species are extremely loyal to favorite spots, with scientists often tagging the same animal at almost the same location where it was first tagged. Individuals exhibit an uncanny ability to hone into favorite feeding spots, even if the particular animal is too young to have visited the location previously. "How or why a young bluefin tuna less than two years of age wakes up in the light of the Sea of Japan and decides to swim to Baja remains completely unknown," says Dr. Block. "Once they get here, tagging data indicate they reside for years, taking advantage of the rich forage off North American coastlines." Fishermen have used those predictable patterns for years. With the increased efficiency of modern fishing methods, this predictability of migratory habits has huge implications, making the need for sound management practices all the more pressing. Fishermen have used those predictable patterns for years, but this new research is allowing a better understanding of migration and feeding behaviors. It's painting a clearer picture of the state of the Pacific and will shed light on the best way forward for developing more effective management practices. The unique scope of the TOPP project data will help fishery managers by detailing where predators are concentrated in the North Pacific and which environmental parameters can be used to predict their occurrence. Both are invaluable in accurately assessing stock conditions while formulating fishing policies. The new data should also aid the recovery of endangered blue whales and other cetacean populations, since electronic tracking data can be used to identify high-use areas where risks such as ship strikes can be minimized. In a similar way, improved understanding of the distribution of leatherback sea turtles and North Pacific albatrosses in relation to pelagic fisheries can lead to smarter policies that help reduce bycatch. "We have a really rich ecosystem off the coast of North America," says Kochevar. And, he notes, "This is intact, from the apex predators down to the plants. That is important." It's important, because there's the implication that with good management practices, all the pieces are in place for the entire ecosystem to thrive for long into the future.

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