Monitoring and evaluating rockfish conservation areas in British Columbia

Abstract

Baseline data for rockfish abundance and substrate associations were documented for newly established rockfish conservation areas (RCAs) in Howe Sound using a multilevel occupancy model, which is new to fisheries science. In 2005, a series of roaming video dives was conducted. Videotapes were scored, minute by minute, according to substrate type, revealing a strong association of rockfish with piled boulders as preferred habitat. Paired divers sighted about twice as many rockfish as were documented on videotape in the same areas (same dates). In 2006, 69 dives were conducted at 11 randomly selected RCA sites and 12 random control sites (three dives per site). Of the factors investigated, only the percentage of boulder coverage predicted rockfish abundance. In 2007–2008, side-scan sonar was deployed for locating boulder piles to streamline efficiency of dive surveys. A combination of telemetry and underwater surveys in randomly selected areas should enable unbiased, noninvasive evaluation of the effectiveness of RCAs in rebuilding populations of inshore rockfish species on the Pacific coast of Canada.