Hypoxia augments edge effects of water column stratification on fish distribution

Fisheries Research
By: , and 



Hypoxic conditions in both freshwater and marine habitats have a significant effect on the distribution of fish in the water column, resulting in some fishes aggregating near the edges of the hypoxic zone. These aggregations may increase fish susceptibility to fishing gears, with attendant effects on stock assessment inferences. We investigated how hypoxic conditions influenced catch rates of yellow perch (Perca flavescens) in both fishery independent bottom trawls and stationary commercial trap nets. Specifically, we examined how the presence of hypoxia affected trap net catch rates and how hypoxia interacted with hypolimnion thickness to modify trawl catch rates. Bottom trawl catch rates were significantly higher in hypoxic conditions than in normoxic conditions, and in each of these scenarios catch rates declined as hypolimnion thickness increased. By comparison, trap net catch rates had a dome-shaped response to the duration of hypoxia with the highest catch rates occurring at intermediate levels. Increased catch rates in hypoxic conditions potentially causes yellow perch population models, which rely on both trap net and trawl indices, to overestimate abundance and could result in overfishing.

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Publication type Article
Publication Subtype Journal Article
Title Hypoxia augments edge effects of water column stratification on fish distribution
Series title Fisheries Research
DOI 10.1016/j.fishres.2020.105684
Volume 231
Year Published 2020
Language English
Publisher Elsevier
Contributing office(s) Great Lakes Science Center
Description 105684, 8 p.
Country United States, Canada
Other Geospatial Lake Erie
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