Assess the ecotoxicological risk associated with the round goby in the St. Lawrence River: Impact of an invasive species on the trophic transfer of contaminants

Context and project description

A small ground fish of European origin that currently abounds in the fluvial portion of the St. Lawrence, the round goby is on its way to creating a new means of spreading contaminating substances: passing them to predator fish, then on to fish-eating birds and possibly then to humans. Very resistant to pollution, the goby colonizes all aquatic areas, including those with low-quality water, such as in plumes of municipal effluent. It feeds on benthic invertebrates and filtering organisms known to concentrate toxins, notably the zebra mussel, which do not consume other fish. Since it has become the main prey of many indigenous predators (walleye, bass, pike etc.), it risks spreading more contaminants to these fish than do other prey. As well, since many of these predators are sport fish, fishers are at greater risk of finding contaminated fish on their plate.

The SLAP partners have judged it crucial to quantify the ecotoxological risk represented by the round goby in order to assess the degree to which it contributes to the transfer of contaminants in the food chain. To carry out their project, the researchers will assess the concentrations of contaminants (classic and emerging interest) found in the sediments of some ten sampling stations along Montréal’s effluent plume. They will then compare the contaminant levels in bodies of gobies with other indigenous prey fish before establishing a link between goby contamination and that of their predators, particularly sport fish.


This project involved measuring the accumulation of a number of conventional and emerging contaminants in prey fish populations in the St. Lawrence, along with the trophic transfer (i.e., transfer up the food chain) of flame retardants. Two articles are currently being drafted: one concerns the trophic transfer of flame retardants (polybrominated diphenyl ethers (PBDE)), and the other compares contaminant levels in the round goby, the yellow perch and the white sucker. A fact sheet on trophic transfer of flame retardants will be published soon.

Participating departments

Government of Canada

  • Environment and Climate Change Canada

Government of Quebec

  • Ministère du Développement durable, de l’Environnement et de la Lutte contre les changements climatiques