MEPS 327:157-170 (2006)  -  doi:10.3354/meps327157

Limited movement in blue rockfish Sebastes mystinus: internal structure of home range

Salvador J. Jorgensen1,3,*, David M. Kaplan1, A. Peter Klimley1, Steven G. Morgan2, Michael R. O’Farrell1, Louis W. Botsford1

1Department of Wildlife, Fish and Conservation Biology, University of California, Davis, California 95616, USA
2Bodega Marine Laboratory, PO Box 247, Bodega Bay, California 94923, USA
3Present address: Tuna Research and Conservation Center, Hopkins Marine Station of Stanford University and Monterey Bay Aquarium, 120 Oceanview Boulevard, Pacific Grove, Callifornia 93950, USA

ABSTRACT: Home range has been estimated for a limited number of marine fishes; however, the use of space and timing of activities within the home range has rarely been studied. In addition, understanding movement patterns of exploited fish species has been identified as a crucial science gap, impeding informed marine reserve design. We used a radio-acoustic positioning telemetry (VRAP) system to monitor detailed movements of 10 blue rockfish Sebastes mystinus around shallow rock pinnacles and stands of bull kelp Nereocystis leutkeana in central California in September 2002. The mean home range was 8783 m2 ± 1137 SE; however, activity was highly concentrated in 1 to 3 core areas within each home range. Mean core areas measured 1350 m2 ± 286 SE, but accounted for ~83% of activity. All core areas were centered over rock pinnacles where rockfish were highly aggregated. Individuals exhibited high site fidelity and made only brief radial excursions away from these centers or moved directly from one pinnacle to the next along defined corridors. Patterns of diel activity and nocturnal sheltering corresponded closely with nautical twilight. Cores overlapped, but estimated locations of nocturnal shelters differed significantly among individuals. Movement patterns were correlated with wind velocity, upwelling index, water temperature and habitat structure.

KEY WORDS: Sebastes mystinus · Rockfish · Movement · Home range · Tagging · Core areas

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