Resilient trout going with the flow
Heavy spring rains and lack of snow to melt this year may not make for the best fishing conditions for trout in rivers and streams, but it’s not bad for the species, says a provincial biologist.
Other effects of climate change, though, like the drought conditions experienced in some of the past few years, can be problematic.
“A few years ago we were having extreme drought, which would be harder on fish than the extreme opposite with heavy rains and cooler temperatures,” says Andrew Lowles, the manager of resource management for the inland fisheries division of the province’s department of fisheries and aquaculture.
“They’re resilient in that they’ve dealt with floods forever, we’re just seeing increased frequency,” Lowles said. “Typically what will happen, in a river system particularly, is trout will just move to the outside and weather the storm in the areas where the current isn’t as strong. As the water subsides, they can move back into their seasonal lies and hiding spots.”
He said high water events are naturally better for the fish than low water events and high temperatures.
Spring droughts can be caused by lack of rain or lack of snow to melt off and replenish the aquifers that gradually release water back into rivers. With the lack of snowfall in recent years, there aren’t the groundwater reserves that come with a slow melt of the snow like years past.
“The lack of snow brings summer forward earlier in the year, and if that goes on, the (river temperature) becomes a little more extreme if there’s not the precipitation to cool them off or refresh the rivers,” Lowles said.
Cool water holds more oxygen, which trout need. When the temperatures get up above 20C fish survival, especially when a trout has fought an angler, can decrease in the warmer water.
The temperatures and drought issues are just two more things native fish have to deal with.
“Over the years, they are continually threatened by changing temperatures, periods of drought and extreme heat … but generally speaking our trout populations are remaining relatively stable,” Lowles said. “Our salmon fishery in areas where it’s open … populations are healthy.”