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Status of Lake Ontario Alewife and 2020 DEC Stocking Plans

Lake Ontario's sportfisheries are world renowned, providing opportunities to catch trophy size fish from a diversity of trout and salmon species. Lake Ontario and its tributaries receive the highest angler effort of all New York's fresh waters, generating over $112 million in angler expenditures annually. In 2019, Lake Ontario anglers continued to experience near-record high fishing quality, particularly for Chinook salmon. Alewife are the primary food for Chinook salmon, and due to concerns with a declining alewife population the New York State Department of Environmental Conservation (DEC) is further reducing Chinook salmon and lake trout stocking levels in 2020. The DEC remains committed to responsible, science-based management of this critical resource to protect the long-term sustainability of the world class trout and salmon fishery and its associated economic benefits.

2020 Lake Ontario Chinook Salmon Stocking

Information about 2020 Lake Ontario Chinook salmon stocking (PDF)

2020 Stocking Plans

  • In response to concerns over ongoing declines in Lake Ontario's adult alewife population, DEC must reduce Chinook salmon and lake trout stocking further to provide adult alewife additional relief from predation.
  • For 2020 Chinook salmon and lake trout stocking will be reduced by an additional 20% from 2019 levels. Naturally reproduced or "wild" fish also contribute significantly to sportfisheries, comprising approximately 50% of Lake Ontario's adult Chinook salmon population.
  • Most Chinook salmon stocked by DEC and the Ontario Ministry of Natural Resources and Forestry (OMNRF) are reared by cooperating sportsmen in net pens, a practice that, on average, doubles fish survival.
  • Lakewide salmon and trout stocking by DEC and OMNRF in Lake Ontario in 2020 will still exceed 3.6 million fish (Table 1). Given favorable wind and water temperature patterns, anglers should expect continued, excellent fishing in 2020.
  • Failure to reduce stocking levels would serve to extend the severity and duration of low adult alewife abundance, with greater potential impacts to the sportfishery.

Table 1. Anticipated lakewide (DEC and OMNRF) 2020 stocking for Lake Ontario.
Species Life Stage Stocking 2020
Chinook Salmon* Spring Yearlings 1,161,568
Lake Trout Yearling equivalents 601,600
Rainbow Trout Spring Yearlings 755,700
Brown Trout Spring Yearlings 556,755
Atlantic Salmon Spring Yearlings 240,000
Coho Salmon Fall Fingerlings 235,000
Spring Yearlings 90,000
3,640,623

* The majority of Chinook salmon will be raised by sportsmen in "net pens," which increases their survival by approximately 2X.

Background:

  • Lake Ontario supports a world class fishery for salmon and trout and in years of good growth produces the largest Chinook salmon in the Great Lakes, with many individuals exceeding 30 pounds.
  • The primary prey fish in Lake Ontario is the alewife, a type of herring native to the Atlantic Ocean that invaded the Great Lakes over 100 years ago.
Different year classes of alewife ages 0, 2 and 4, arranged on a measuring board to show size differences
  • Lake Ontario Chinook salmon feed almost exclusively on adult alewife, requiring large numbers of alewife to support a voracious appetite that allows a salmon to grow to over 30 pounds in four years.
  • In 2016, Lake Ontario fisheries management agencies were concerned about declining numbers of adult alewife in future years due to consecutive, poor alewife reproduction in 2013 and 2014 (2013 and 2014 "year classes"). These poor year classes will continue to affect the overall stability of Lake Ontario's alewife population for several more years.
  • In 2016, the Lake Ontario Committee (DEC and OMNRF) announced that stocking levels for Chinook salmon and lake trout would be adjusted down 20% in 2017 to reduce predator demand on adult alewife in order to protect the valuable fishery.
  • Chinook salmon and lake trout stocking targets remained at the 20% reduced level in 2018.
  • Chinook salmon stocking was reduced by an additional 20% in 2019.

The 2019 Alewife Bottom Trawl Survey

  • The alewife population is monitored by the U.S. Geological Survey, DEC and OMNRF with bottom trawls in early spring, and the 2019 survey was the most extensive fish survey ever conducted on Lake Ontario with 252 bottom trawls. Please see B.C. Weidel et al. 2019 "Preliminary status of Lake Ontario Alewife based on the 2019 spring trawl survey (2019)" (leaves DEC website) for detailed results of the 2019 survey, and alewife biomass projections for 2020.
  • The 2019 lakewide adult alewife (age 2 and older) biomass index declined 29% relative to 2018.
  • The lake-wide age-1 alewife biomass index in 2019 declined relative to 2018 and was the lowest value observed since whole-lake sampling began in 2016.
  • Managers were pleased to see strong alewife reproduction in 2016. Those fish now appear to be under intense predation pressure.
  • The current biomass, size structure, and age structure of the adult alewife population reflect the relatively poor alewife reproductive success observed in the 2013- and 2014-year classes.
  • Alewife reproductive success was also below average in 2017 and 2018, suggesting adult alewife biomass will decline further in 2020.

Additional information for anglers

Additional information for anglers (PDF)

Reference

Weidel, B.C., J.P. Holden and M.J. Connerton. 2019. Preliminary status of Lake Ontario Alewife based on the 2019 spring trawl survey. A report from the Lake Ontario Prey Fish Working Group to the Lake Ontario Committee. Great Lakes Fishery Commission's Lake Ontario Committee. Ann Arbor, MI.

Read the reference (leaves DEC's website).