The Ovary Development Cycle in Adolescent Pacific Rockfish: A Potential Source of Bias in Estimating Length at 50% Maturity

A large number of histological studies of ovary development and female maturity in Pacific rockfishes have demonstrated a pattern in adolescent rockfish of abortive maturation via mass atresia of oocytes from a vitellogenic stage.  Macroscopic staging of developing ovaries is partly based on external visual detection of the presence of vitellogenin in oocytes, thus  adolescent rockfish might frequently be incorrectly classifed as functionally mature.  As a result, maturity curves based on macroscopic staging of samples from early in the seasonal cycle of ovary development should consistently underestimate the length or age at 50% maturity relative to samples collected later in the season, when most mature females have released their larvae.  I test this hypothesis using a large historical sample of macroscopic maturity data collected for synchronous, winter spawning rockfish collected from Oregon’s commercial trawl fishery.