Through ingenious use of technology, biologists are checking out the mystery of coaster brook trout—literally. They are collecting data using bar codes, in a system similar to those used by supermarkets.
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| Passive Integrated Transponders or PIT tags. Photo: Barry Wojciechowski |
The mystery is why certain young brook trout — called coaster brook trout or coasters — suddenly head down tributaries to the big waters of Lake Superior to become adult lake-dwellers. Hundreds of juvenile fish in study streams will be caught and small electronic tags will be surgically implanted in their body cavities. Bar code readers will be set up along the banks of streams flowing into Nipigon Bay. As the fish move, the readers will record the data imprinted on their electronic tags.
Those recordings will enable biologists to learn what fish are passing through, in what direction, and also what percentage of tagged fish are leaving the stream; whether or not they are re-entering; and when, and under what conditions, they are migrating. Another benefit: the tags will record information about a fish’s lifetime.
The data collection in this multi-year partnership program with the federal department of Fisheries and Oceans Canada will not answer all questions as to why some streams continually produce wandering brook trout, but it should provide crucial pieces in the puzzle.
Most importantly, the collected data will become invaluable in creating a larger, comprehensive plan for the future protection of coaster brook trout in Nipigon Bay and Lake Superior.
Click here to view a map of the project area
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About the Brook Trout Tags
• The tag’s technical name is passive integrated transponder, and its nickname is PIT tag. A PIT tag is a sliver of glass containing a computer chip and coil of wire; the PIT tag is used to identify individual fish.
• Because a PIT tag is just slightly larger than a grain of rice (about 23 mm long), surgically implanting one in a fish’s body cavity does not change its external appearance and has little or no influence on its growth rate, behaviour, health or predator susceptibility.
• PIT tag technology has been used in North America, beginning in the U.S., for about 20 years to permanently identify individual animals. Tag monitoring and identification was first used in fisheries studies, but then expanded for use with mammals, reptiles, amphibians and birds. The use of external reading systems also means animals do not need to be recaptured, which reduces handling time and stress.
Project Partners:
- Thunder Bay Fly Fishers
- North Shore Steelhead Association
- Fisheries and Oceans Canada
For more information, contact:
- Marilee Chase, COA Lake Superior Basin Coordinator, Upper Great Lakes Management Unit – Lake Superior, Ministry of Natural Resources, Thunder Bay (807) 475-1371