Natal Homing and Connectivity in Atlantic Bluefin Tuna Populations
Jay R. Rooker,1*
David H. Secor,2*
Gregorio De Metrio,3
Ryan Schloesser,1
Barbara A. Block,4
John D. Neilson5
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.
2 Chesapeake Biological Laboratory, University of Maryland Center for Environmental Science, Post Office 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.
* These authors contributed equally to this work.
To whom correspondence should be addressed. E-mail: rookerj{at}tamug.edu
