Lake Ontario benthic prey fish assessment, 2015

NYSDEC Lake Ontario Annual Report 2015-12b
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Benthic prey fishes are a critical component of the Lake Ontario food web, serving as energy vectors from benthic invertebrates to native and introduced piscivores. Since the late 1970’s, Lake Ontario benthic prey fish status was primarily assessed using bottom trawl observations confined to the lake’s south shore, in waters from 8 – 150 m (26 – 492 ft). In 2015, the Benthic Prey Fish Survey was cooperatively adjusted and expanded to address resource management information needs including lake-wide benthic prey fish population dynamics. Effort increased from 55 bottom trawl sites to 135 trawl sites collected in depths from 8 - 225m (26 – 738 ft). The spatial coverage of sampling was also expanded and occurred in all major lake basins. The resulting distribution of tow depths more closely matched the available lake depth distribution. The additional effort illustrated how previous surveys were underestimating lake-wide Deepwater Sculpin, Myoxocephalus thompsonii, abundance by not sampling in areas of highest density. We also found species richness was greater in the new sampling sites relative to the historic sites with 11 new fish species caught in the new sites including juvenile Round Whitefish, Prosopium cylindraceum, and Mottled sculpin, Cottus bairdii. Species-specific assessments found Slimy Sculpin, Cottus cognatus abundance increased slightly in 2015 relative to 2014, while Deepwater Sculpin and Round Goby, Neogobius melanostomus, dramatically increased in 2015, relative to 2014. The cooperative, lake-wide Benthic Prey Fish Survey expanded our understanding of benthic fish population dynamics and habitat use in Lake Ontario. This survey’s data and interpretations influence international resource management decision making, such as informing the Deepwater Sculpin conservation status and assessing the balance between sport fish consumption and prey fish populations. Additionally a significant Lake Ontario event occurred in May 2015 when a single juvenile Bloater Coregonus hoyi, was captured during the spring bottom trawl survey at 95m (312 ft) near Oswego, NY. This native, deep-water prey fish, last captured in Lake Ontario survey trawls in 1983, is part of an international, collaborative coregonid restoration effort in the Great Lakes.

Study Area

Publication type Report
Publication Subtype State or Local Government Series
Title Lake Ontario benthic prey fish assessment, 2015
Series title NYSDEC Lake Ontario Annual Report
Series number 2015
Chapter 12b
Year Published 2016
Language English
Publisher New York State Department of Environmental Conservation Division of Fish, Wildlife and Marine Resources
Publisher location Albany, NY
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 2015 Annual Report Bureau of Fisheries Lake Ontario Unit and St. Lawrence River Unit to the Great Lakes Fishery Commission’s Lake Ontario Committee
First page 12b-12
Last page 12b-23
Conference Title Lake Ontario Committee Meeting
Conference Location Niagara Falls, ON
Conference Date March 31- April 1, 2016
Country Canada, United States
Other Geospatial Lake Ontario
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