Cowcod Rebuilding Analysis 2005 Analysis of the Progress towards rebuilding in the Southern California Bight

Introduction Cowcod (Sebastes levis) population status was initially assessed by Butler et al (1999) and declared overfished in 2000. The original stock assessment was conducted using a Delay-Difference model that estimated recruitments as a random walk function. The model estimated that the spawning stock abundance was 7% of an unfished stock in 1999 and that resilience of the stock was low. The original cowcod rebuilding analysis was completed using a surplus production model because of the density dependent population growth inherent in the logistic equation. The surplus production rebuilding analysis was modeled using a log-normal distribution fitted to recruitment (1951-1998) estimated in the original delay difference model (Butler et al. 1999). A subsequent rebuilding analysis (Butler and Barnes 2000) estimated the following rebuilding parameters and quantities that were adopted by the PFMC in 2004 (PFMC 2004):