CATOS: Champlain Acoustic Telemetry Observation System
Tracking Fish Movement in Lake Champlain
- By Jason Dana Stockwell
Drs. Ellen Marsden and Jason Stockwell at the University of Vermont’s Rubenstein Ecosystem Science Laboratory are building the Champlain Acoustic Telemetry Observation System (CATOS) to remotely track the movements of fish to answer a number of ecological and fisheries management related questions. CATOS, which is modeled after a similar system in the Great Lakes (GLATOS), uses acoustic telemetry technology to follow fish as they move around in Lake Champlain. The system works by surgically implanting a transmitter about the size of an AA battery into a fish. The transmitter periodically emits an acoustic signal (a ‘ping’) that is detected by receivers strategically placed in the lake. To date, 12 acoustic receivers have been deployed throughout Lake Champlain; the next 14 receivers will be added in 2014, with plans to continue expanding coverage. Receivers passively detect and record tagged fish that move within their range (~ 1.5 km radius). The CATOS infrastructure supports a diversity of projects involving fish movement. Accumulated data are downloaded 2-3 times per year, and each project is provided with detection data pertaining to its tagged fish.
Two current projects that use the CATOS array focus on lake trout behavior and impacts of habitat fragmentation on fish movements. Lake trout disappeared from Lake Champlain by 1900, though the causes of this disappearance are poorly understood. Lake Champlain has been stocked with lake trout since the 1970s but, to date, natural reproduction has been unsuccessful. A better understanding of lake trout spawning behavior will improve restoration efforts. To address this problem, 30 lake trout were tagged in 2013 to investigate movements and spawning site fidelity. Male lake trout were predicted to remain at spawning sites to attract roaming females. Tori Pinheiro, a graduate student working on the project, has already found some interesting patterns. "Our preliminary data suggest male and female lake trout are on the move during spawning season. We had one lake trout travel from near Grand Isle on South Hero Island to Arnold Bay in only 8 days", says Pinheiro.
The second project will examine the effect of habitat fragmentation resulting from the causeways on Lake Champlain. Lake whitefish are abundant in the Main Lake but scarce in Missisquoi Bay where they were historically commercially fished. Coldwater species such as whitefish would likely be limited in their movement through the shallow causeway openings in summer, due to thermal lake stratification. The CATOS array will be used to monitor whitefish movement between the Main Lake, Missisquoi Bay, and the Northeast Arm to determine whether they are, in fact, swimming through these openings.
CATOS will foster greater collaboration among institutions by facilitating data-sharing and encouraging communication among agencies and research institutions about ongoing projects and potential research avenues. The unified system will also allow researchers and managers to collaborate on receiver placement, surgical techniques, study design, etc. Discussions with partner institutions on future projects are already underway and include studies on movement of walleye, lake sturgeon, and Atlantic salmon.