With warming temperatures and melting of the ice, we are seeing a considerable amount of fish winterkill in Wascana Lake. Due to the cold winter and increased ice cover on the lake, there's less oxygen that's being accessible to the fish which is fairly typical to the longer winter like we have had.
Maintenance staff will collect deceased fish along the shorelines and dispose of them properly to allow for full, enjoyable use of the Centre. We will not be retrieving deceased fish in the middle of the lake as it poses a safety risk for staff. The fish are also an important part of the cycle of nature serving as food for its predators.
With regards to the lake, we have been monitoring the water levels and quality throughout the year, especially over the winter. Dissolved oxygen refers to the level of free, non-compound oxygen in the water and is necessary to aquatic organisms including invertebrates, fish, plants and bacteria. We will continue to monitor the overall quality of the lake and the fish population, as best as possible, in order to assess the severity of the winterkill on populations.
Over the winter the levels of dissolved oxygen in Wascana Lake were really low and therefore could possibly have led to a winterkill. Common Carp are one of the main fish species in our lake and are a hardy invasive species. These fish can endure dissolved oxygen levels above 5 mg/L or even levels below 2 mg/L, generally staying within our usual dissolved oxygen range. However, this winter the levels dropped to levels that could be fatal for some fish species which is why we are presently witnessing the winterkill. This does not mean that all fish in Wascana Lake have perished and we will continue to monitor the lake to determine the severity.