Movement patterns of black rockfish (Sebastes melanops) in Oregon coastal waters

Movement patterns of black rockfish (Sebastes melanops) in Oregon coastal waters

S.J. Parker, P.S. Rankin, J. M. Olson, and R.W. Hannah

Movement patterns of black rockfish (Sebastes melanops) in Oregon coastal watersThis is part of Biology, Assessment, and Management of North Pacific Rockfishes
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Description

We studied the movement patterns of black rockfish (Sebastes melanops) in Oregon coastal waters to estimate home range over daily to annual time scales, determine if females relocate during the reproductive season, and evaluate the influence of environmental variation on movement. We moored 18 acoustic receivers in a 3 × 5 km array south of Newport, Oregon, at depths from 9 to 40 m. We then surgically implanted 42 black rockfish (34-48 cm total length [TL]) with coded, pressure transmitters having an approximate lifespan of 6 months. Fish were tagged in August (n = 6), September (n = 13), October (n = 7), and February (n = 8 depth and 8 non-depth). Fish were temporarily absent from the monitored area for short periods (usually <7 days) indicating limited travel outside the monitored area. Seven fish left the area permanently. During one full year of monitoring, home ranges were relatively small (55±9 ha) and did not vary seasonally. Absences of females >39 cm (likely mature) from the array were longer in duration than for mature males, especially during the reproductive season (November, January, and February), but both sexes had the longest absences during April through July. These data indicate that black rockfish in open coastal waters live in a very restricted area for long periods as adults, but may relocate periodically. A small home range could make them susceptible to local depletion from targeted fishing, but also make them good candidates for protection using marine reserves.

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