Educational Video January 29, 2015
How We Do Things at IISD-ELA is a series of videos that highlight research conducted by scientists at the IISD Experimental Lakes Area (IISD-ELA), a unique freshwater science research facility in northwest Ontario, Canada.
Have you ever wondered what a fish does during the day? How about at night? Since fish live under the water, it is difficult to know what they do and where they go without going under the water yourself. Fortunately, IISD–ELA scientists have a remote method of figuring out where fish spend their time: acoustic telemetry. They implant large-bodied fish such as lake trout and northern pike with specialized tags that send out signals called “pings” every few minutes. An array of data loggers suspended in the lake records these pings, which are downloaded by IISD-ELA researchers. After the information is processed in specialized software, researchers can see exactly where the tagged fish are in the lake 24 hours a day. This is a great method of observing fish in their natural habitat, and one that has been used at the Experimental Lakes Area for more than 10 years.
Scientists implant these tags into the gut cavity of the fish by performing a quick surgery while the fish is under anesthesia. This video shows IISD–ELA biologist Lee Hrenchuk conducting surgery on a lake trout from Lake 373, one of IISD–ELA’s Long Term Ecological Monitoring (LTER) lakes. The fish was captured by angling and immediately brought to shore for surgery. After the surgery and a brief period of recovery, the fish was released back into the lake and will be tracked for the next three and a half years (the approximate tag life). Fish with implanted tags have a great survival record and are consistently recaptured in good health many years after the tags have run out of battery power. IISD–ELA scientists are currently tracking lake trout in five lakes as part of the Water Diversion study, LTER program, Freshwater Aquaculture study, and Mysis Reintroduction experiment.