|
Natal Homing and Connectivity in Atlantic Bluefin Tuna Populations |
 |
 |
 |
|
Meeresbiologie -
Science
|
|
Geschrieben von: Vincent
|
 Originally published in Science Express on 2 October 2008
Science 31 October 2008:
Vol. 322. no. 5902, pp. 742 - 744
DOI: 10.1126/science.1161473
Reports
Natal Homing and Connectivity in Atlantic Bluefin Tuna Populations
Jay R. Rooker,1*{dagger} 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.
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, 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:
Diese E-Mail-Adresse ist gegen Spambots geschützt! JavaScript muss aktiviert werden, damit sie angezeigt werden kann.
Tuna Mix
Bluefin Tuna are split into two populations. The western population spawns in the Gulf of Mexico and the eastern population spawns in the Mediterranean Sea. The western population is in a particularly vulnerable state, and conservation management zones that are currently arbitrarily demarked by 45°W longitude do not seem to be alleviating the population decline. In an attempt to find out why tuna management is ineffective, Rooker et al. (p. 742, published online 2 October) have taken cores from otoliths in the fishes' ears and measured carbon and oxygen isotope ratios to obtain a chemical signature characteristic of the fishes' birthplace. Adolescent fish from both populations, oblivious to the 45°W management boundary, mix on their extensive migrations to feed in the Atlantic Ocean. As the tuna mature they exhibit a strong tendency to return, like salmon, to their birthplace to spawn. Unexpectedly, the waters around the Gulf of Maine and St. Lawrence were refugia for mature adults from the western population, which may have implications for revising tuna management across international boundaries.
|
|
|
wer ist Online
Wir haben 18 Gäste online
|
