By Derek Kim | Published 06/16/13 9:08pm
That tuna you ate for lunch is causing a significant environmental shift thousands of miles away.
A new study conducted by MSU scientists, along with help from the Smithsonian Institution and eight other organizations, has found evidence that the effects of open-ocean fishing is changing the foraging habits of the endangered Hawaiian Petrel.
“The fact that the Hawaiian Petrel has moved almost a whole trophic level down means that what they are eating now is estimated to be … around one-seventieth of what they ate before,” said Anne Wiley, MSU alumna and current Smithsonian postdoctoral researcher. “It’s a huge reduction in the average size of their prey.”
The Hawaiian Petrel is a dark gray-brown and white seabird that is known for its strong flying ability. Petrels can be found from the Equator to the most northern latitudes of the Western Hemisphere.
During her study, she examined isotope data from modern Hawaiian Petrels and bones from subfossils as old as 4,000 years to see how feeding habits have changed throughout the centuries. Older samples had consistently high nitrogen isotope ratios, which indicated a diet of large prey high on the food chain. In contrast, samples from less than a century ago — which is when industrial fishing began — had low ratios, indicating that they fed on smaller prey such as fish and squid.