Fisheries Bycatch, Vessel Strikes and Other Sources of Human-Caused Mortality

Background

Quantifying human-caused mortality and serious injury (M/SI) is integral to producing marine mammal stock assessments. Sources of human-caused M/SI include fishery bycatch, marine debris entanglements, shootings, acoustic trauma, and vessel strikes.

  1. We use fishery observer data to provide annual estimates of marine mammal bycatch in fisheries along the U.S. West Coast (Carretta 2024), and to identify environmental factors and fishing gear improvements to reduce bycatch risk. We work with the Pacific Offshore Take Reduction Team that includes fishermen, conservation organizations, and scientists, to evaluate bycatch trends in the U.S. West Coast swordfish gillnet fishery and implement strategies for bycatch reduction (Barlow and Cameron 2003). Our involvement in bycatch reduction and assessment led to the introduction of acoustic pingers into the swordfish gillnet fishery in the 1990s, which resulted in the elimination of beaked whale bycatch and large reductions in the bycatch of other marine mammal species.

  2. Other sources of human-caused mortality and serious injury include vessel strikes, shootings, marine debris entanglements Carretta et al. 2024, and acoustic trauma (St.Leger and Danil 2011)

Annual MMPA SAR requirements to enumerate human-caused M/SI

Annually, accounting for human-caused M/SI is required to 1) produce an annual human-caused M/SI Technical Memorandum and 2) update SARS.

The annual human-caused M/SI is produced in the format of Carretta et al. (2024), based on R-Markdown code (“CARRETTA/Github/HCM_SI/HCM_SI_Report.RMD”) and the R-Script ‘SeriousInjuryExtract.R’. This is located in the “CARRETTA/Github/HCM_SI” folder = R-Studio Project (not a package).

The annual report is based on data-mining an Excel file “Anthropogenic_Mortality_Serious_Injury_Carretta.xls” that is updated annually. The annual human-caused M/SI report includes the most-recent 5 years of data to inform SARS.
Many contacts exist for acquiring human-caused M/SI data that inform Pacific SARS, including individual states (CA sea lion removals under Sec. 120 of the MMPA robert.c.anderson@noaa.gov ), regional offices (AK, WCR), with a roster including Justin.Greenman@noaa.gov, Lauren.Saez@noaa.gov, Nancy.Young@noaa.gov, Amelia.Brower@noaa.gov, Amanda.Bradford@noaa.gov, Kayleigh.Somers@noaa.gov .

Bycatch Estimation in CA Swordfish gillnet fishery

This fishery is scheduled for phase-out in 2027, stay tuned. Only a handful of vessels participating. Data is housed at PacFin and requires a login and a data confidentiality agreement. The files used for data manipulation and analysis are in the directory “C:/CARRETTA/Github/DGNBycatch” (R-Studio project, not a package). The entire workflow including data download, variable selection, and bycatch estimation is found in the HTML file: “C:/Carretta/GitHub/DGNBycatch/R/DGN_Bycatch_Workflow.html”, Which is generated via “C:/Carretta/GitHub/DGNBycatch/R/DGN_Bycatch_Workflow.RMD”

People to know: charles.villafana@noaa.gov (Observer program). He knows all the PacFin folks housing the data, including: Ryann Turcotte RTurcotte@psmfc.org , and Robert Ryznar RRyznar@psmfc.org

SeriousInjury R-Package and Shiny App

A Shiny Tool and R-Package used to assess the probability of death for large whale injuries. It is under consideration for use as a NMFS National Policy for assessing large whale injuries. Based on the Carretta and Henry (2022) publication. Two identical Github repositories exist for the SeriousInjury package: https://github.com/SWFSC/SeriousInjury https://github.com/JimCarretta/SeriousInjury

Once installed, the function SeriousInjuryTutorial( ) opens an HTML window. You can also run the Shiny App, based on instructions in the tutorial.

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