The core fish program at IISD-ELA monitors the general condition of fish in our lakes. Fish do not always respond immediately to external influences, so our sampling activities are designed to assess long-term responses to whole-ecosystem experiments and broad regional shifts (such as climate change). We monitor all fish species present in our lakes, including sport fish such as lake trout, lake whitefish, northern pike, and yellow perch; benthic feeding fish, such as white sucker; and forage species, such as fathead minnow, dace, and shiners.
We use consistent sampling methods in both reference and experimental lakes. The backbone of our program involves trap-netting to capture a range of fish species, sizes, and sexes for mark-recapture and catch-per-unit effort analyses. We estimate abundance and population structure and assess the growth, survival, and body condition of fish. Together, these data illustrate the variability and trends in our fish communities, whether due to natural fluctuations or experimental manipulations.
To augment our population data, we conduct additional sampling activities for the many experimental manipulations that occur at IISD-ELA. As our lakes and their resident fish populations are small, it is essential that we remove as few animals from the systems as possible. To do this, we use non-lethal sampling methods, such as fin clips (stable isotopes of carbon and nitrogen), fin rays (age determination), gastric lavage (diet composition), muscle biopsies (contaminant concentrations), and mucus swabs (stress biomarkers), among others, with an emphasis on developing new non-lethal sampling procedures.
While much of our work involves directly handling fish, for more than two decades, researchers at IISD-ELA have also employed a more hands-off approach by tracking fish remotely using acoustic telemetry systems. Acoustic transmitters are implanted in the gut cavities of fish with a minimally invasive surgical procedure (see a video here). These transmitters allow us to continuously monitor individual fish locations in several IISD-ELA lakes, providing answers to important questions like habitat requirements, space use, activity levels, and winter behaviour.
Types of data/samples collected in this program:
Note that some fish data are available directly by request, but requests for data that require additional processing (such as population estimates) must be discussed with fish crew researchers.