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Balancing prey availability and predator consumption: A multispecies stock assessment for Lake Ontario

March 30, 2022
Trophic interactions are drivers of ecosystem change and stability, yet are often excluded from fishery assessment models, despite their potential capacity to improve estimates of species dynamics and future fishery sustainability. In Lake Ontario, recreational salmonine fisheries, including Chinook salmon (Oncorhynchus tshawytscha) and lake trout (Salvelinus namaycush), depend on a single prey species, alewife (Alosa pseudoharengus). To accommodate strong trophic interactions among species, we developed a multispecies statistical catch-at-age assessment (MSCAA) model that links the dynamics of the salmonine fisheries and alewife via prey consumption and predator growth. We found that prey availability had declined since 2015 due to decreased alewife recruitment and increased Chinook salmon biomass, leading to higher alewife mortality rates and lower predator growth rates. Forward projections of predator–prey dynamics suggest that Chinook salmon stocking reductions may improve the probability for alewife population growth, but could be counteracted by increased natural Chinook salmon recruitment. Combined with predator- and prey-monitoring efforts, multispecies assessments show promise as models of intermediate complexity to support a transition to ecosystem-based approaches to fisheries management.
Publication Year 2022
Title Balancing prey availability and predator consumption: A multispecies stock assessment for Lake Ontario
DOI 10.1139/cjfas-2021-0126
Authors Kimberly B. Fitzpatrick, Brian C. Weidel, Michael J. Connerton, Jana R. Lantry, Jeremy P. Holden, Michael J. Yuille, Brian F. Lantry, Steven R. LaPan, Lars G. Rudstam, Patrick J. Sullivan, Travis O. Brenden, Suresh Sethi
Publication Type Article
Publication Subtype Journal Article
Series Title Canadian Journal Fisheries and Aquatic Sciences
Index ID 70240487
Record Source USGS Publications Warehouse
USGS Organization Coop Res Unit Leetown; Great Lakes Science Center