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Request for Assistance with Lake Ontario Fish Diet Study

Why we are doing a predator diet study in 2020

Over the last 20 years the food web in Lake Ontario has changed in response to invasive species and reduced nutrient input. Prey fish like rainbow smelt have declined while new species like round goby have invaded and increased in predator diets. We are conducting this diet study in collaboration with the U.S. Geological Survey to compare 2020 results with previous work conducted in 1999, 2006, 2008, and 2013.

We are using stomach samples (entire digestive tract) from angler-collected salmon, trout, walleye, and bass to determine the current species and size composition of predator fish diets in Lake Ontario, and to see if they have changed relative to previous studies. For example, we are wondering if salmonids are consuming fewer alewife, more gizzard shad and round goby, or whether predators are consuming different sized prey than they have in the past. Angler-collected stomachs from salmon, trout, walleye, and bass provide critical data that link important sport fish to the food web. We will have a network of freezers located around the lake where anglers can drop off samples. The freezers will also contain data cards and zip lock bags.

What information anglers will collect

  1. Stomachs (digestive tracts) from all sizes and species of salmon and trout, walleye and smallmouth bass. Collections must be limited to legal sized fish and volunteers must not exceed daily creel limits.
  2. We will provide anglers with "stomach data cards" (example on next page) and zip-lock bags. Each stomach collected should be placed in its own bag with a completed "stomach data card". Please use only pencil to fill out the card. Data cards and bags will be located in sample drop off freezers.
  3. Save stomachs from all fish you harvest in a day - regardless of how "full" or "empty" they appear. Empty stomachs are important data and may actually contain preyfish bones. Please place only one sample and tag in each bag.
  4. Save the entire digestive tract. Cut the digestive tract as close to the gills as possible and as close to the vent as possible. Place the digestive tract and the stomach data card in the bag. Make sure all food items get in the ziplock bag - even if the stomach is nicked during cleaning.
  5. Record the following information on the stomach data card: Angler name (optional), date, port you were fishing out of, species, and total length (measured if possible).
  6. If possible, keep the sample bag on ice and freeze as soon as possible.
  7. We plan to collect samples from freezers once per week. Please call Mike Connerton at 315-654-2147 if freezer is nearly full or malfunctioning or you have any questions.

Diet Study Data Card (PDF)

Thank you in advance for contributing to this important project!

Front of Lake Ontario Diet Study Card
Front of Lake Ontario Diet Study Data Card
Back of Lake Ontario Diet Study Card
Back of Lake Ontario Diet Study Card
Freezer Location for Lake Ontario Fish Diet Study
Location Latitude Longitude
Fort Niagara State Park Cleaning Station 43.260500 -79.058350
Wilson - Bootleggers Marina 43.313667 -78.841972
Olcott - Town of Newfane Marina Cleaning Station 43.336282 -78.717636
Rochester - Shumway Marina Gas Dock 43.251741 -77.608563
Fairhaven - Bayside Marina Cleaning Station 43.314825 -76.718921
Oswego - US Geological Survey, 17 Lake Street 43.462620 -76.517095

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  • Contact for this Page
  • NYSDEC-Lake Ontario Fisheries Unit
    541 East Broadway
    PO Box 292
    Cape Vincent, NY 13618
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