Lake trout spawning studies: Updates, new survey, and comparison to standard September gillnet survey

New York State Department of Environmental Conservation Report of Investigations -11
By: , and 

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Abstract

In Lake Ontario, lake trout restoration efforts have not established a self-sustaining population. Herein we describe efforts to evaluate standard and new surveys, and to estimate dispersal from stocking locations, to better understand impediments to natural reproduction. In 2019, lake trout egg deposition was sampled at two locations, Stony Island Reef, and Ford Shoals. No eggs were collected at either site. Egg deposition rates at Stony Island Reef, expressed in eggs/net/day, were lower in 2019 (0) and 2017 (0.0004) than in 1987 and 1989 (1.27 and 0.27, respectively). Spawning lake trout were indexed using standard gillnets set at six locations along the southern shore. Sites were fished overnight with two nets, except Youngstown where only one net was set. When comparing the standard September gillnet survey to the spawning survey, the spawning survey caught more and older fish, but had a similar representation of strains. Both gillnet surveys revealed that, during the early to late fall, most lake trout (>72%) are caught as adults near where they were stocked as juveniles. This spawning survey demonstrated that lake trout in spawning condition are aggregating near possible spawning habitat, but the presence of adults alone cannot identify the specific spawning habitat. Egg deposition results suggest lake trout may be depositing eggs in different habitats then they have in the past. Alternatively, our egg collection methods may not be effective when egg abundance is low. Lake Ontario lake trout restoration would benefit from survey approaches that identify specific spawning habitat.

Study Area

Publication type Report
Publication Subtype State or Local Government Series
Title Lake trout spawning studies: Updates, new survey, and comparison to standard September gillnet survey
Series title New York State Department of Environmental Conservation Report of Investigations
Chapter 11
Year Published 2020
Language English
Publisher New York State Department of Environmental Conservation
Contributing office(s) Great Lakes Science Center
Description 12 p.
Larger Work Type Report
Larger Work Subtype State or Local Government Series
Larger Work Title 2019 Lake Ontario Unit Annual Report
First page 11-1
Last page 11-12
Country Canada, United States
Other Geospatial Lake Ontario
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