By Jordanna N. Bergman, PhD Student, Carleton University and Steven J. Cooke, Professor, Carleton University
The Rideau Canal Waterway is a 202 km route of picturesque lakes, rivers, and artificial canals connected by 23 active lockstations and 45 locks. Originally constructed in the mid 1800s to facilitate commercial and military transport between Lake Ontario and the Ottawa River, today the Rideau Canal is almost entirely operated to support recreational, cultural, and economic activities. In fact, the system is so iconic and unique that it received World Heritage Site designation from the United Nations. Managed by Parks Canada, the lock system is used by recreational boaters, canoeists, and kayakers during the navigation season (mid-May to mid-October) to travel throughout the waterway. With pristine aquatic habitats and one of the most diverse fish communities in Canada, the Rideau Canal is home to firstclass fishing and supports an important tourismbased industry for eastern Ontario. Trophy gamefish can be found in the waterway, including Largemouth and Smallmouth Bass (Micropterus salmoides and M. dolomieu), Muskellunge (Esox masquinongy), and northern pike (Esox lucius).
Have you ever wondered what else might be passing through locks with you beneath the surface? There’s a chance as you travel through a lockstation, fish are travelling right alongside you. Although lockmasters, anglers, and boaters have reported seeing fish inside locks, little is known about fish movement and behaviour related to lock-and-dam infrastructure. Do fish purposefully move through locks, or is it accidental? If they do move through locks, to what extent?
Are movements species-specific and/or seasonally driven? Students in the Fish Ecology and Conservation Physiology Lab at Carleton University are using acoustic telemetry equipment and generous help from anglers to investigate fish movements and the ecological connectivity of the Rideau Canal Waterway.
Biotelemetry, the tracking of animals using electronic tags, provides information on movement patterns of wild fish necessary to conservation and management efforts. Acoustic transmitters (i.e. tags) are surgically implanted into focal fish species and emit an underwater sound signal that sends unique identification information about that specific fish to acoustic receivers. Receivers, which are strategically placed beneath the water surface throughout the waterway prior to tagging, receive the sound signals and convert them to digital data that can be used to determine tag positions.
In the summer of 2019, we acoustically tagged 245 fish; these include two gamefish species, largemouth bass and northern pike, and two invasive species, common carp (Cyprinus carpio) and round goby (Neogobius melanostomus) Additional efforts and experimental projects were focused on northern pike given that they are known to travel relatively long distances (up to 8km daily). The team deployed 90 acoustic receivers throughout the waterway in the spring and in November they will be braving the cold to retrieve them to download data and analyze fish movement patterns.
Another interesting aspect of our acoustic telemetry research involves the inclusion of invasive species. We acoustically tagged both common carp and the recently discovered round goby this past summer. Round Goby are of special concern as they are a newly introduced invasive species to the Rideau Canal. We are hopeful that we may be able to prevent their further spread by understanding, and exploiting, their spatial ecology (when and where a species distributes themselves over time to reside, avoid predation, forage, and for sexually mature individuals, reproduce). Round Goby were first documented in the canal during a scheduled water drawdown in Edmonds Lockstation in Smiths Falls in 2018. The round goby is a small (25cm max), highly aggressive, bottomdwellingfish that has been observed to predate on the eggs and young of nesting gamefish, appears to contribute to increased incidences of avian botulism, and as a result of competitive exclusion, often displaces native species to suboptimal habitat. Although our team struggled to capture round goby for weeks (a bittersweet sign, as we interpret this to mean population densities are still low) we finally identified a successful capture method using a backpack electrofishing unit. We implanted acoustic tags into 45 Round Goby. Upon retrieval of our acoustic receivers in November, round goby movements will be at the top of the list for analysis.
In addition to the aforementioned electronic tagging studies, we are also conducting an extensive external tagging study to investigate broadscale fish movements in the Rideau Canal. We are striving to tag and release 10,000 fish with external identification tags, also known as anchor tags. Besides a unique ID number, the tag also has contact information (email: email@example.com and phone number: (613) 520-2600 x4377) for anglers to report their catches. By partnering with anglers who report their catches of tagged fish, we can compare the original location the fish was tagged to the recapture location, and importantly, determine if that fish passed through any barriers (e.g. locks, dams) to adjacent water bodies. To date, we have tagged approximately 4,500 fish and will continue to tag fish until we reach our goal. Tagged fish species include Black Crappie (Pomoxis nigromaculatus), Bluegill (Lepomis macrochirus), Bullhead (Ictalurus spp.), Largemouth and Smallmouth Bass, Northern Pike, Pumpkinseed (Lepomis gibbosus), Rock Bass (Ambloplites rupestris), Yellow Perch (Perca flavescens), Walleye (Stizostedium vitreum), Lake Trout (Salvelinus namaycush), White Sucker (Catastomus commersoni), Common Carp (Cyprinus carpio), and Muskellunge. To date, 171 fish have been recaptured as of October 2019, none of which were recaptured in canal reaches other than where they were initially tagged.
Over the next three years our team will continue working towards meeting the objective of tagging 10,000 fish and acoustically tagging a variety of fish species. By analyzing acoustic telemetry data in conjunction with anglerrecapture data, we hope to better understand fish connectivity in the Rideau Canal Waterway and use that information to support economically important gamefish and simultaneously minimize invasive species impacts. If you are curious to learn more about our research, or see a video of how fish are tagged, you can check out our Facebook page: https://www.facebook.com/Cook eFECPL/ or visit our lab website at http://www.fecpl.ca/