Home site fidelity in Black Rockfish, <em>Sebastes melanops</em>, reintroduced into a fjord environment

Abstract

Between December 2004 and January 2007, we studied the movements of six Black Rockfish (Sebastes melanops) that had been fitted with acoustic transmitters and reintroduced into a fjord environment at the edge of Vancouver Harbour, British Columbia. The Black Rockfish were released in December 2004 and April 2005 at a reef characterized by complex rocky structures and steep slopes; bottom depths at the site dropped from 10 to 55 m within a horizontal distance of only 30 m. The reef, however, is small (approximately 4500 m2) and is surrounded by soft bottom habitats used infrequently by Black Rockfish. VEMCO VR2 receivers were deployed at the release site and at outlying reefs located 1 and 4 km away. Acoustic data suggest that one individual emigrated from the reef after 11 months of residency and a second individual disappeared abruptly after 6 weeks on the reef, possibly due to fishing mortality or emigration. The four remaining individuals appear to have confined their movements to the release site, using an area 6 to 10 times smaller than the home ranges reported for populations in low-gradient coastlines in California and Oregon.