Rockfish biology

Rockfish (Sebastes sp.) are a clade of finfish that includes over 65 species in the Northeast Pacific, with 30 to 36 found commonly off the coast of BC (Love et al., 2002). Considered mid-level predators and important prey source, rockfish are an essential species to the Salish Sea food-webs (Obaza et al., 2023). Rockfish are sedentary, long-lived, and slow growing, with life expectancies often exceeding 50 years.

Rockfish experience delayed age of reproductive maturity ranging between five and seven years, and can be as old as 20 years or 50 cm before first reproduction (Leaman, 1991). Rockfish also tend to experience low first-year survival. Females are oviviparous (eggs are brooded inside the female then expelled as free-swimming larvae) and can produce between 10,000 to nearly three million larvae, depending on the species, size, or age (Love et al., 2002). These life-history traits, resulting in long generation times, make rockfish highly susceptible to fisheries mismanagement and stock declines.

Rockfish have complex courtship rituals that occur in the fall followed by a delayed internal fertilization. giving birth to larvae four to eight weeks later. Larvae are pelagic, with movement subject to ocean currents, until they eventually settle on rocky reefs. Settlement typically occurs when fish are about 3 cm to 9 cm in length and between three to six months of age (Love et al., 2002). Habitat associations for larvae include structure and relief, for example kelp and other vegetation over rock outcrops, cobbles and/or boulders.

History of BC’s Rockfish fishery

The post-contact history of the rockfish fishery in British Columbia (BC) began as accidental bycatch from the Lingcod (Ophioden elongatus) fishery, beginning in the mid 1800’s and ramping up until the mid 1950’s (Cass et al., 1990). Directed fisheries pressure towards rockfish began in the 1970’s in response to a growing and lucrative demand locally and grew without restrictions until the early 1990’s (Yamanaka & Logan, 2010). Total Allowable Catch (TAC) quotas were implemented in the early 1990’s, and incrementally reduced over the years in response to declining catch rates.

Rockfish Conservation Areas (RCAs) where established between 2004 and 2007 to address growing conservation concerns for inshore species, which live in rocky nearshore areas at depths of 0 to 200 m. Key species inhabiting inshore habitats include quillback (S. maliger), yelloweye (S. ruberrimus), copper (S. caurinus), tiger (S. nigrocinctus), china (S. nebulosus), and black (S. melanops) rockfish.

Despite these measures, numerous studies have consistently shown minimal to no positive impact of RCAs compared to non-RCA sites for any fish species (Dunham et al., 2020; Haggarty et al., 2016; Marliave & Challenger, 2009). While the lack of effectiveness of RCAs is complicated, a few key issues have been highlighted by various investigations. One such factor is a lack of compliance from recreational fishers. Illegal fishing is commonly observed within RCAs in Átl’ka7tsem/Howe Sound and throughout the province of BC (Haggarty et al., 2016). Despite high compliance from commercial fisheries, fishing effort from recreational fishers has remained the same (or has even increased) in 86% of RCAs throughout BC, potentially masking any positive impacts RCAs to fish recovery. A recent comprehensive report also suggests that many RCAs are too small for them to be effective (Dunham et al., 2020) while other sites do not contain enough suitable habitat for rockfish and other demersal fish species (Dunham et al., 2020; Haggarty et al., 2016; Marliave & Challenger, 2009).

In order to address identified threats and to evaluate the effectiveness of RCAs, DFO conducted an in-depth analysis of current RCAs based on size, depth, connectivity, and habitat (Dunham et al., 2020). Based on these ecological attributes, current RCAs were scored and ranked in order to determine the conservation benefit of each area. While some RCAs scored high, many did not, including several sites within Átl’ka7tsem/Howe Sound (Dunham et al., 2020), suggesting that current management levels are having little to no impact in the recovery of rockfish species. As a result of this analysis, DFO has made several recommendations to improve the effectiveness of RCAs. Proposed changes include extending current boundaries, rescinding areas which are ranked as being ineffective (ex. minimal rockfish habitat), and combining glass sponge closures with nearby RCAs (Dunham et al., 2020). DFO is currently engaging in talks with various stakeholders regarding proposed changes and new management plans are not expected until later than 2025.

DFO has also noted that as of 2018, a monitoring program has not been established for rockfish despite it continually being identified as an effective tool in the management and recovery of rockfish species (Dunham et al., 2020; DFO, 2021). The lack of a coast wide monitoring program has also been identified as a key reason why current evaluation of the effectiveness of RCAs is extremely challenging (Dunham et al., 2020). The fact that rockfish populations are still in a state of slow recovery, the lack of a robust monitoring plan, and the issues identified with existing RCA effectiveness, highlights the need for ongoing monitoring to better inform and evaluate management measures.

Learn more about MLSS’ rockfish monitoring programs by clicking our links below or find additional resources here.