Presentation Title

From bycatch to center stage: using incidental catch of forage fish in bottom trawls to inform survey design

Project Collaborators

Amelia McReynolds (Graduate Student Mentor), Jason D. Stockwell, J. Ellen Marsden

Abstract

Forage fish populations provide an important link in food webs between lower trophic levels and predators. Declines in forage fish abundance can limit production of ecologically and economically important piscivores. The Rubenstein Ecosystem Science Laboratory at the University of Vermont is designing a survey to assess forage fish in Lake Champlain. The survey will continue and improve long-term monitoring efforts (1995-2015) by the Vermont Fish & Wildlife Department (VTFWD). We explored trends in forage fish “bycatch” data from a 5-year juvenile lake trout bottom trawl survey to examine the status of the forage fish community after the VTFWD survey ended. Cluster analysis using flexible beta linkage on abundance estimates of common species identified four clusters that were not distinctly separated. Sampling region in the Main Lake (north, central, south) and year interacted to shape relative abundance estimates of each species, indicating variable patterns in forage fish distribution. For dominant species, we estimated sampling effort required to assess relative abundance based on inter-trawl variability. Our analysis of these data will guide future assessments by providing estimates of sampling effort required to sufficiently sample important forage species and describing how trends in forage fish distribution and habitat use may influence abundance estimates.

Primary Faculty Mentor Name

Jason Stockwell

Secondary Mentor NetID

jmarsden

Secondary Mentor Name

J. Ellen Marsden

Graduate Student Mentors

Amelia McReynolds

Status

Undergraduate

Student College

Rubenstein School of Environmental and Natural Resources

Program/Major

Wildlife and Fisheries Biology

Primary Research Category

Biological Sciences

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From bycatch to center stage: using incidental catch of forage fish in bottom trawls to inform survey design

Forage fish populations provide an important link in food webs between lower trophic levels and predators. Declines in forage fish abundance can limit production of ecologically and economically important piscivores. The Rubenstein Ecosystem Science Laboratory at the University of Vermont is designing a survey to assess forage fish in Lake Champlain. The survey will continue and improve long-term monitoring efforts (1995-2015) by the Vermont Fish & Wildlife Department (VTFWD). We explored trends in forage fish “bycatch” data from a 5-year juvenile lake trout bottom trawl survey to examine the status of the forage fish community after the VTFWD survey ended. Cluster analysis using flexible beta linkage on abundance estimates of common species identified four clusters that were not distinctly separated. Sampling region in the Main Lake (north, central, south) and year interacted to shape relative abundance estimates of each species, indicating variable patterns in forage fish distribution. For dominant species, we estimated sampling effort required to assess relative abundance based on inter-trawl variability. Our analysis of these data will guide future assessments by providing estimates of sampling effort required to sufficiently sample important forage species and describing how trends in forage fish distribution and habitat use may influence abundance estimates.