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. The DEC is conducting a diet study in collaboration with the U.S. Geological Survey to compare 2020 results with previous work conducted in 1999, 2006, 2008, and 2013.
The study will be based upon using stomach samples of the 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, the study will see 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.
A network of freezers have been set up around the lake where anglers can drop off samples. The freezers will also contain data cards and zip lock bags.
One may ask what exactly does a study like this entail, especially from an angler perspective? Well here are the procedures to follow and hopefully clear up any questions.
The study is seeking 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.
The DEC will provide anglers with “stomach data cards”and Ziploc bags. Each stomach collected should be placed in its own bag with a completed “stomach data card”. Please use pencils only to fill out the card. Data cards and bags will be located in sample drop off freezers.
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.
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.
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).
If possible, keep the sample bag on ice and freeze as soon as possible.
The DEC plans to collect samples from freezers once per week. Please call Mike Connerton at 315-654-2147 if the freezer is nearly full or malfunctioning or you have any questions.
There are currently six freezer stations up and running for drop-off. The locations are as follows (general location followed by detailed longitude/latitude coordinates of the precise freezer location which may be typed directly into a mapping app or GPS device):
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 (43.462620-76.51709)