A Simple Method for Estimating Survival Rate from Catch Rates from Multiple Years

—Survival rates can be estimated from annual surveys by tracking the abundance of one or more cohorts, as measured by catch per unit of sampling effort, from one year to the next. However, it can be difficult to attain reasonable precision unless sampling effort is extensive. Indeed, estimates of survival exceeding 100% are not infrequently obtained. We show that data from several years can be analyzed simultaneously to obtain a single estimate of survival under the assumption that survival is constant over the period analyzed. The method requires that only a single cohort be identified and separated from the other agegroups. Thus there are minimal data requirements. Estimates of the survival of goosefish Lophius americanus obtained by this method compare favorably with estimates obtained by analyzing changes in mean length over time. Annual survival rate, S, can be estimated from annual surveys in various ways. Most methods are based on the relationships