Presentation Title
From bycatch to center stage: using incidental catch of forage fish in bottom trawls to inform survey design
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 Name
J. Ellen Marsden
Graduate Student Mentors
Amelia McReynolds
Faculty/Staff Collaborators
Amelia McReynolds (Graduate Student Mentor), Jason D. Stockwell, J. Ellen Marsden
Status
Undergraduate
Student College
Rubenstein School of Environmental and Natural Resources
Program/Major
Wildlife and Fisheries Biology
Primary Research Category
Biological Sciences
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.