research

Surveying the Davidson Seamount: Where are the Humbolt Squid?

Submitted by eloury on Wed, 2010-08-04 09:17

by Julie Stewart, MARINE curriculum intern

The NOAA research vessel MacArthur II recently journeyed to the Davidson Seamount, an extinct underwater volcano about 80 miles offshore from the Monterey Peninsula. Our mission was to conduct surveys of the marine mammals and seabirds in the area. The seamount is about 26 miles long by 8 miles wide, and comes as shallow as 1.5 kilometers below the surface (the seafloor otherwise sits around 3.5 kilometers deep). This is a very productive area: as deep currents hit the seamount, they are redirected up towards the surface, so there are high concentrations of krill and other plankton that provide food for higher predators.

While remotely operated vehicles (ROVs) have documented some of the seafloor (discovering amazing soft corals, among other things), little was known about the marine mammal and seabird populations so far from shore. Read more...

Gulf oil spill overlaps critical bluefin tuna habitat during spawning season.

Submitted by eloury on Fri, 2010-06-25 14:12

This map shows the track (yellow line) and daily positions (dots) of an electronically tagged giant bluefin tuna, which spent March 23-May 24, 2009, in the Gulf of Mexico. The track is overlaid on the area of the Deepwater Horizon oil spill as of May 24, 2010 (black). (Credit: Tag-A-Giant Foundation and Stanford University)

by Erin Loury

Science Communication Intern/M.S. Candidate at Moss Landing Marine Labs

The Gulf of Mexico oil spill may spell big trouble for the Atlantic bluefin tuna, one of the most commercially valuable species that is already beleaguered by overfishing. The area of the Deepwater Horizon spill coincides with critical bluefin spawning grounds, which the fish return to with amazing fidelity, a new study finds.

Dr. Steven Teo of the University of California at Davis and Dr. Barbara Block of Stanford University recently published a paper in the journal PLoS ONE, which reveals pronounced differences in habitat use between bluefin and yellowfin tuna in the Gulf of Mexico. Using electronic tagging and fisheries catch data, Teo and Block discovered that bluefin are highly specific in their habitat use. These giant fish select cool, productive water masses in the slope waters of the northern Gulf of Mexico, with a site fidelity reminiscent of salmon returning to their natal streams. In contrast to yellowfin tuna, which are more widely distributed throughout the warm Gulf waters, "The bluefins' habitat requirements are relatively exact, so we can predict with reasonable accuracy where bluefin tuna are likely to be spawning at any given time based on oceanographic data,” Dr. Teo said.

Unfortunately, this predictive power leads to a troubling prognosis in the wake of the Deepwater Horizon oil spill. Read more...