Animals in Marine Sanctuaries Not Immune to Human Impact

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http://www.livescience.com/40887-national-marine-sanctuaries-stress-top-predators.html

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Now, a team of scientists based at the University of California, Santa Cruz have conducted the first study that maps the potential cumulative impacts of human activities on marine predators along the West Coast. They focused on animals at the top of the food chain — such as blue whales, California sea lions, leatherback sea turtles and black-footed albatrosses — because these animals play a crucial role in maintaining healthy ecosystems by preying on invasive species and helping to keep biodiversity high.

"What we wanted to do was not just understand where the animals were going, but also where they were likely to be most affected," said study co-author Sara Maxwell, a researcher at Stanford University's Hopkins Marine Station. "We wanted to get the most bang for our buck."The team used existing maps of the travel routes of eight top predators — collected through the Tagging of Pacific Predators (TOPPS) program that has been tracking thousands of marine predators using satellite and light-based geolocator devices since 2000 — and compared these tracks with maps representing the cumulative effect of 24 different human-made stressors to determine where high-stress areas overlap with regions of elevated animal traffic. [Gallery: Ocean Creature Census]

The researchers found that many of the areas with the greatest cumulative negative impacts on the predators fell within National Marine Sanctuaries. This finding was not entirely unexpected, they said, because many of these sanctuaries occur close to shore and, therefore, are more vulnerable to human activity than areas farther from the coast are.

But this does not necessarily mean that the 13 sanctuaries — which span more than 150,000 square miles (390,000 square kilometers) of the U.S. Pacific, Atlantic and Gulf coasts — are not serving their designated purpose, Maxwell said. The sanctuaries were originally created in 1972 to protect marine animals from oil and gas activity, in response to the 1969 Santa Barbara oil spill (the largest oil spill in U.S. waters at the time, but since surpassed in size by the 1989 Exxon Valdez and 2010 Deepwater Horizon spills), Maxwell said. In that sense, they are doing their jobs by limiting oil traffic.