Canary rockfishes Sebastes pinniger return from the brink: catch, distribution and life history along the US west coast (Washington to California)

ABSTRACT: A standardized bottom trawl survey monitored the recovery of canary rockfishes Sebastes pinniger along the US west coast. We examined catch-per-unit-effort (CPUE), distribution and life history parameters for canary rockfishes, an important groundfish that severely limited other US west coast fisheries from 2000 to 2015 due to their overfished status. Average catch varied among years, but CPUE, tows with positive catch and biomass significantly increased since 2007. Weight-length and size-at-age relationships varied by regions separated at key biogeographic breakpoints. Weight increased more rapidly as a function of length north of Point Conception, California, regardless of gender. Growth rates of females and maximum size of males increased with latitude, with the greatest increases north of Pt. Conception. Mature females most commonly occurred north of Cape Mendocino and at depths >115 m. Observed variations in spatial patterns (CPUE and distribution) and life history characteristics combined with reduced occurrence of large/old canary rockfishes south of Cape Mendocino suggest coast-wide differences that imply the existence of distinct biological stocks. However, since annual von Bertalanffy growth coefficients and slopes of weight-length regressions appear related to basin-wide (Pacific Decadal Oscillation) and regional (based on in situ data) climatic effects, environmental variation may also contribute to the differences observed here.