Fish Migration: Channel Catfish and a Freshwater Mussel

By Tys Theijsmeijer, Sr. Director Ecosystem Stewardship, Royal Botanical Gardens

Removing barriers in migration routes is a global initiative and this weekend, May 25 is World Fish Migration Day. World Fish Migration Day is a one-day global celebration to raise awareness for the importance of free-flowing waterways and their relevance to fish populations. In support of this global awareness day the Cootes Paradise Fishway will be open for public visitation on Sunday, May 26.  Some of the largest fish of the season migrate into spawn at this time, including the Channel Catfish (a native species) and the Common Carp (invasive species). Barriers and fish passageways are intensive area of activity on the Great Lakes. 

The Channel Catfish is a remarkable example of ecological linkages and the importance of fish migrations, including the recent appearance of the Mapleleaf Mussel in local waterways. The Channel Catfish ranges over very large regions and is overall one of the largest freshwater fish in North American. During the spring it travels into inlets such as Cootes Paradise Marsh to spawn. At the Cootes Paradise Fishway it is in the top three species for size with the largest recorded measuring 79 cm long and weighing 9.2kg (passing through in 2018). Freshwater mussels take advantage of migrating fish as hitchhikers. Mussel species develop quite fish species specific hitchhiking relationships. The Mapleleaf mussel, during its larval phase attaches to the gills of a channel catfish and rides along to a new habitat location. However, a barrier such as an old dam in the travel corridor prevents fish travel and subsequent mussel recolonization of habitat. For the recovering local habitat maintaining migration has been a success. For the Mapleleaf mussel the closest next area where the are found is the Niagara Region, and Jordan Harbour specifically, a substantial trip for a Channel Catfish!

Illuminating the movements of fish has become a focal project of research. For the Great Lakes we have GLATOS (Great Lakes Telemetry Observation System Observation System). For several years now Cootes Paradise Marsh hosts fish telemetry monitoring devices recording the presents and movements of tagged fish for the Lake Ontario System – the local project is lead by the Great Lakes Lab for Fisheries and Aquatic Sciences, although no Channel Catfish are tagged currently as part of the program. 

Overall dam removals or creation of fish passageways to restore fish populations and migrations routes is an ongoing global initiative ranging from massive hydro dams to small scale old mill dams. Work to recover the American Eel in Lake Ontario is the most substantial area initiative with the Hydro Dam on the St. Lawrence River the main challenge. Restoring fish migration routes is a top priority for the fishery and is found in initiatives of all levels of government, and in the Great Lakes Agreement between Canada and the United States, and with many small local groups taking initiative in their areas.  The ability to complete a dam removal project requires years of work and public support so take a minute to consider what old, abandoned dams are blocking fish migrations near you. To learn more, visit the Fish Migration Foundation.