Submitted on June 6, 2008
Accepted on September 17, 2008
Natal Homing and Connectivity in Atlantic Bluefin Tuna Populations
Jay R. Rooker 1
*, David H. Secor 2, Gregorio DeMetrio 3, Ryan Schloesser 1, Barbara A. Block 4, John D. Neilson 5
1 Department of Marine Biology, Texas A&M University, 5007 Avenue U, Galveston, TX 77551, USA.
2 Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, P.O. Box 38, Solomons, MD 20688, USA.
3 Department of Animal Health and Well-Being, University of Bari, 70010 Valenzano (Bari), Italy.
4 Stanford University, Hopkins Marine Station, Oceanview Boulevard, Pacific Grove, CA 93950, USA.
5 Department of Fisheries and Oceans, Population Ecology Section, St. Andrews Biological Station, St. Andrews, NB Canada.
* To whom correspondence should be addressed.
Jay R. Rooker , E-mail: rookerj{at}tamug.edu
These authors contributed equally to this work.
Atlantic bluefin tuna populations are in steep decline, and an improved understanding of connectivity between individuals from eastern (Mediterranean Sea) and western (Gulf of Mexico) spawning areas is needed to manage remaining fisheries. Chemical signatures in the otoliths of yearlings from regional nurseries were distinct and served as natural tags to assess natal homing and mixing. Adults showed high rates of natal homing to both eastern and western spawning areas. Trans-Atlantic movement (east to west) was significant and size-dependent, with individuals of Mediterranean origin mixing with the western population in the U.S. Atlantic. The largest (oldest) bluefin tuna collected near the northern extent of their range in North American waters were almost exclusively of western origin, indicating that this region represents critical habitat for the western population.
