Bay-Delta Catchability Study Active
Addressing Catchability Bias in Fish Surveys
San Francisco Bay and the Sacramento-San Joaquin Delta collectively make up the "Bay-Delta." In the scientific study of fish, "catchability" refers to the probability that a fish will be captured by a particular fishing gear or method. Catchability is a measure of how effectively a fishing gear or method can capture fish. "Catch data" refer to information about the quantity and species composition of fish. Catch data are used by scientists to study the biology, ecology, and behavior of fish populations. Catchability bias is a term used to describe a situation where the catch rate of a fishery is not directly proportional to the abundance of fish in the water. In other words, the catchability of fish is not constant and can be influenced by a variety of factors. Catchability can lead to inaccurate assessments of fish populations and the effectiveness of management measures. Therefore, catchability bias can have important implications for fisheries management. To account for catchability bias, scientists and managers may use statistical models or other methods to adjust catch data and estimate the true abundance of fish in the water.
Problem Description
Fish surveys play a major role in decision-making about water operations within the San Francisco Estuary. However, no survey is 100% efficient at capturing all fish available to the survey gear. This lack of perfect catchability can potentially be a significant source of bias and lead to inaccurate conclusions because multiple surveys are often combined to assess the structure and functioning of the San Francisco Estuary ecosystem.
Study Objectives
The goal of this study is to develop analytical methods that can be used to determine the relative amounts of catchability bias among longterm fish surveys in the San Francisco Estuary.
Study Approach
We will use open science initiatives within the San Francisco Estuary that have made multiple longterm fish monitoring surveys publicly available to test for relative differences in catchability among surveys. We will fit statistical models to catch data for multiple fish species and size classes to explain spatial and temporal patterns in catch. We will also include a survey effect in the analysis to account for potential catchability effects on observed catch data. The survey effect on the catch can then be interpreted as relative differences in catchability among surveys because the spatial and temporal effects on catch have already been incorporated into the analysis.
Relative bias in catch among long-term fish monitoring surveys within the San Francisco Estuary
Addressing Catchability Bias in Fish Surveys
San Francisco Bay and the Sacramento-San Joaquin Delta collectively make up the "Bay-Delta." In the scientific study of fish, "catchability" refers to the probability that a fish will be captured by a particular fishing gear or method. Catchability is a measure of how effectively a fishing gear or method can capture fish. "Catch data" refer to information about the quantity and species composition of fish. Catch data are used by scientists to study the biology, ecology, and behavior of fish populations. Catchability bias is a term used to describe a situation where the catch rate of a fishery is not directly proportional to the abundance of fish in the water. In other words, the catchability of fish is not constant and can be influenced by a variety of factors. Catchability can lead to inaccurate assessments of fish populations and the effectiveness of management measures. Therefore, catchability bias can have important implications for fisheries management. To account for catchability bias, scientists and managers may use statistical models or other methods to adjust catch data and estimate the true abundance of fish in the water.
Problem Description
Fish surveys play a major role in decision-making about water operations within the San Francisco Estuary. However, no survey is 100% efficient at capturing all fish available to the survey gear. This lack of perfect catchability can potentially be a significant source of bias and lead to inaccurate conclusions because multiple surveys are often combined to assess the structure and functioning of the San Francisco Estuary ecosystem.
Study Objectives
The goal of this study is to develop analytical methods that can be used to determine the relative amounts of catchability bias among longterm fish surveys in the San Francisco Estuary.
Study Approach
We will use open science initiatives within the San Francisco Estuary that have made multiple longterm fish monitoring surveys publicly available to test for relative differences in catchability among surveys. We will fit statistical models to catch data for multiple fish species and size classes to explain spatial and temporal patterns in catch. We will also include a survey effect in the analysis to account for potential catchability effects on observed catch data. The survey effect on the catch can then be interpreted as relative differences in catchability among surveys because the spatial and temporal effects on catch have already been incorporated into the analysis.