Document Type

Report

Department/Program

Virginia Institute of Marine Science

Publication Date

3-2017

Abstract

In this study we estimated calibration factors necessary to maintain the long‐term integrity of the juvenile striped bass surveys in the Chesapeake Bay region. These surveys provide annual indices of recruitment (estimated as juvenile fish abundance in summer) and are used by fisheries managers in Virginia and Maryland to inform adjustments of annual harvest limits for striped bass from the commercial and recreational fisheries in Chesapeake Bay. During the multi‐decadal history of the survey, a potentially influential change occurred: VIMS deployed a net (the VA net) with a mesh material that differed from the standard net that MD DNR continued to deploy (the MD net). More recently, another change was necessitated when neither the standard net material nor the net material recently used by VIMS was available for construction of replacement nets. Hence, a net using new mesh material was constructed and experimentally deployed in 2015 (new net). Paired net hauls (n=144) were completed in Maryland and Virginia nursery areas during summer 2015 to permit estimation of calibration factors: 70 pairs with the VA‐MD nets, 42 pairs with the MD‐New nets, and 32 pairs with the VA‐new nets. Not all paired hauls captured a given target species, however. Three sets of calibration factors were estimated from using beta‐binomial models that accounted for differences in capture efficiencies and variation in the relative capture success of the nets. We considered the effects of several environmental covariates (e.g., temperature, salinity, and turbidity) as well as deployment characteristics (e.g., bottom type, calendar day, and maximum net extension) on the relative efficiency of nets and on the variation in the probability of capture among paired hauls. More...

DOI

https://doi.org/10.21220/V5D605

Keywords

Striped bass, Chesapeake Bay, fish stock assessment, fish populations

Creative Commons License

Creative Commons Attribution 3.0 License
This work is licensed under a Creative Commons Attribution 3.0 License.