Scientists were startled to see two key migratory paths emerge as they laid down data points for each tagged animal as they tracked it over time. The map reveals interspecies' attraction to key ecosystems rich in food and natural resources. Source: Dr. Randy Kochevar, Stanford University.
group of animals simultaneously, they would be able to gain new insights into how various species of wildlife live together in the open ocean.
Rich Discovery Deployments of 4,306 electronic tags over a decade yielded 1,791 individual animal tracks from 23 species. This mass of data is still being analyzed, but it reveals overlapping patterns for marine wildlife migrations and habitats and shows that ocean life is not evenly scattered throughout the seas. Instead, species appear to follow distinct pathways. Two "hotspots" run perpendicular to each other. The California Current stretches south along the U.S. West Coast, while the North Pacific Transition Zone flows east/west where Alaska's cold, subarctic water abuts the subtropical waters of Hawaii. The Channel Islands are part of a massive interspecies annual migration pathway that scientists compare to a watery Serengeti. "These are the oceanic areas where food is most
abundant…these areas are the savanna grasslands of the sea," Block said. "Knowing where and when species overlap is valuable information for efforts to manage and protect critical species and ecosystems." The data gathered wasn't just about migratory
paths. For the first time, scientists could observe how often a particular animal dove, how far it dove, how long it stayed at certain depths, and how diving affected its own blood and temperature. "When elephant seals are swimming through the
ocean, they dive 50 to 60 times per day to depths of 500 to 600 meters," explains Kochevar. "Every dive, the tag takes measurements of the temperature with the depth so we are creating a profile of the water column. We get similar profiles from tags on tuna. (When someone harvests a tuna, he could get a $1,000 reward for returning the tag.) Essentially, we have a fleet of animal oceanographers going to really cool
Whales, like this humpback (above), and dolphins (below) have been increasingly visible in the Channel Islands in recent years.