Presentation Abstract
Yelloweye Rockfish in the Puget Sound/Georgia Basin were listed under the Endangered Species Act (ESA) in 2010, and a formal recovery plan for these species was published by NOAA Fisheries in 2017. Under this recovery plan, the criteria for delisting or downlisting are specified as certain levels of spawning potential ratio (SPR), which compares the reproductive capacity of a stock in its current condition relative to an unfished condition. SPR is a proxy for relative stock biomass, a commonly used metric of stock status. Although these metrics can be estimated without catch histories, catch histories improve our understanding of population dynamics over time, a useful addition to monitoring ESA recovery, but historical removal histories were not available for these distinct population segments (DPSs). We therefore reconstructed the catch history from fisheries records and collated length data from contemporary and historical hook-and-line surveys to fit a data-limited version of a statistical catch-at-age model. Small sample sizes and low confidence in the historical catch data translated into large uncertainty intervals in the population dynamics of the species. Despite this uncertainty, the stock assessment model estimated Yelloweye Rockfish is above 25% of unfished biomass (the limit biomass reference for federally managed rockfishes on the Pacific coast) under the assumption of deterministic recruitment. However, in line with recent genetic evidence, the DPS of Yelloweye Rockfish listed under the ESA extends from south Puget Sound to Queen Charlotte Strait in British Columbia. The Canadian portion of this population is currently estimated to be at 32% of unfished biomass (95% quantiles: 15 to 68%). Thus, the disjunction between the biological boundaries of the population and the jurisdictional boundaries between Canada and the U.S. present an additional source of uncertainty in assessing recovery.
Session Title
Data Science 2
Conference Track
SSE1: Science for the Future
Conference Name
Salish Sea Ecosystem Conference (2022 : Online)
Document Type
Event
SSEC Identifier
SSE-traditionals-112
Start Date
28-4-2022 8:30 AM
End Date
28-4-2022 10:00 AM
Rights
Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this document for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.
Type
Text
Language
English
Data-limited fisheries methods shed light on the exploitation history and population dynamics of ESA-listed Yelloweye Rockfish in Puget Sound, Washington
Yelloweye Rockfish in the Puget Sound/Georgia Basin were listed under the Endangered Species Act (ESA) in 2010, and a formal recovery plan for these species was published by NOAA Fisheries in 2017. Under this recovery plan, the criteria for delisting or downlisting are specified as certain levels of spawning potential ratio (SPR), which compares the reproductive capacity of a stock in its current condition relative to an unfished condition. SPR is a proxy for relative stock biomass, a commonly used metric of stock status. Although these metrics can be estimated without catch histories, catch histories improve our understanding of population dynamics over time, a useful addition to monitoring ESA recovery, but historical removal histories were not available for these distinct population segments (DPSs). We therefore reconstructed the catch history from fisheries records and collated length data from contemporary and historical hook-and-line surveys to fit a data-limited version of a statistical catch-at-age model. Small sample sizes and low confidence in the historical catch data translated into large uncertainty intervals in the population dynamics of the species. Despite this uncertainty, the stock assessment model estimated Yelloweye Rockfish is above 25% of unfished biomass (the limit biomass reference for federally managed rockfishes on the Pacific coast) under the assumption of deterministic recruitment. However, in line with recent genetic evidence, the DPS of Yelloweye Rockfish listed under the ESA extends from south Puget Sound to Queen Charlotte Strait in British Columbia. The Canadian portion of this population is currently estimated to be at 32% of unfished biomass (95% quantiles: 15 to 68%). Thus, the disjunction between the biological boundaries of the population and the jurisdictional boundaries between Canada and the U.S. present an additional source of uncertainty in assessing recovery.
