New Research Published on Climate Change Impacts on Marine Predators
shark, photographed at the Farallon Islands off Northern California and
tagged with an acoustic tag (front) and a pop-up satellite tag (rear) as
part of the TOPP research program.
bluefin tuna are the super-athletes of the ocean. TOPP researchers followed
several of them to migrate all the way across the Pacific basin, from
California to Japan and back in a matter of months. Credit: TOPP. Copyright
Randy Wilder, Monterey Bay Aquarium.
lions tagged as part of the TOPP project. Credit: Dan Costa, UC Santa Cruz.
September 24, 2012
Unlike human habitat, temperatures in the marine environment cannot be
controlled by a thermostat. So what do marine animals do when the heat
cranks up? NOAA Fisheries scientist Elliott Hazen (AFS member, '11) led a
research team with 11 U.S. and Canadian scientists to find out exactly how
climate change impacts apex predators-animals at the top of the food chain.
The results of their work are now published in Nature Climate Change in this
Based out of the Southwest Fisheries Science Center in Pacific Grove,
California, Dr. Hazen combined information from the 4,300 apex predators
tagged through the Tagging of Pacific Predators (TOPP) Program
> and climate
change scenarios based on predictions by the Intergovernmental Panel on
Climate Change. By the year 2100, Hazen and his colleagues found some
predators could be facing up to a 35 percent loss of habitat as the ocean
water with their preferred temperature moves northward.
Dr. Hazen predicted different responses from different predator "guilds"
like seabirds, sharks, tunas, turtles, whales, seals, and sea lions. Those
that have a very specialized diet and limited range of temperatures they can
tolerate, such as salmon sharks, blue sharks, and mako sharks face the
biggest challenges. Others, like seabirds and tunas, might actually see
their habitat grow.
Two of the most important habitats in the Pacific Ocean are known as the
North Pacific Transition Zone and the California Current and they fared very
differently. Migratory species that head to the North Pacific Transition
Zone for the cooler temperatures might find their route a bit longer as the
zone moves as much as 600 miles northward. Those who stay within the
California Current-right along the coast of California-may do better, as the
massive upwelling of nutrients helps protect the zone from major changes
even as the temperature warms.
Dr. Hazen chose to study apex predators because they help control and
structure food webs in the ocean. His study is the first to use not only sea
surface temperature predictions, but also models of chlorophyll-a, the green
pigment found in phytoplankton, the microscopic plant-like plankton that are
at the bottom of the food web. Where phytoplankton are abundant,
zooplankton, small fish, larger fish, and apex predators are sure to follow.
This study leverages the resources of NOAA, NASA, National Science
Foundation, and a number of international partners engaged in characterizing
the marine environment by using direct and remotely-sensed measurements and
integrating numerical simulations.
Dr. Hazen hopes his findings can identify which species are the most
vulnerable to new threats so we can focus conservation efforts on those who
need it most. Read Dr. Hazen's 6-page paper here
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