Science activity

Recent review efforts of fish surveys within the San Francisco Estuary (SFE) have acknowledged concerns about catchability bias because catch data plays a significant role in decision-making about water operations. Catchability is a source of bias defined as the proportion of the available population captured and retained by surveying gear. Numerous factors could be responsible for catchability bias, potentially leading to inaccurate conclusions about mechanisms responsible for trends in fish communities observed from monitoring surveys. For example, decreasing catch with increasing submerged aquatic vegetation (SAV) could either reflect that fewer fish use SAV or that catchability decreases with increasing SAV. This project will use generalized additive models to create relative catchability estimates among the major SFE fish monitoring surveys and use this information to address issues of catchability bias when inferring fish population and community dynamics from catch data collected within the SFE.