Last Sunday my friend and I took a fly fishing trip down the Cowichan river in our pontoon boats. We each caught and released several fine trout, both rainbow and browns, and we marveled at the largely undisturbed beauty of the river.
We had intended to use his aluminum drift boat, but the river is now running at 15 cubic meters per second and it is too low for the larger drift boats. We had to navigate through rocks in some of the rapids that become more challenging and more fun as the river drops. This is one of the best times of the year for trout fishing in our river as many of the rainbows from the lake enter the river to spawn and the insect hatches are very strong for all the fish to fatten up before the doldrums of our warm water summers.
The lake is now below full storage, which is the top of the weir, and dropping every day. The snowpack is now almost completely gone, two weeks earlier than last year, so our only source of inflows to the lake will be from the spring rains, if they come. We will maintain the river flow at 15 cubic meters per second until June 15 to provide adequate habitat for late emerging steelhead fry and to ensure remaining chinook and coho fry can find wetted areas near the riverbanks to find the food that is essential for their survival. It is critical that emerging fry can find shelter and adequate food for growth during their first days and weeks of life. Studies have shown that gaining weight early gives them a much better chance of returning as adults to spawn.
We are taking a risk to maintain the river flows we need for fish at this time of year. We know how important it is for fry survival so we willingly allow the lake to go below full storage to protect our fish stocks. Climatologists are predicting an El Nino event for this summer and that means it will be warm and dry again this year. Starting the spring with the lake below full storage is not the ideal situation when another dry summer is probably coming. On June 15 we will be halving the river flow to 7 cubic meters per second as we try to hold as much water as possible behind the weir and hope we get the rain we need to recharge our lake and make it through the dry season. By that time most of the Chinook fry will be in the estuary and the coho and steelhead fry will have had a good start to life and we hope they will adapt to the decreased flows and rising temperatures in the river.
This dramatic decrease in river flow is carefully managed by very slowly closing the weir gates over several days. This is done to allow the fry that are in pools near the river’s edge have time to adapt and hope that they will move out of the drying pools before they get isolated and cut off from the river. On our recent float trip we found a small pool near the river with about 50 coho fry stranded in it. We were able to use a fine meshed fish net to move them back into the river where they have a chance to survive. In the coming weeks many of the fry will become stranded in spite of our weir management efforts and people like Joe Saysell will be out on the river, rescuing fry and returning them to the main flow. Joe is a retired river guide who has lived on the river all of his life and he knows all the places that trap fry as the river drops. Every year he rescues thousands of fish that would otherwise perish.
Joe is one of many citizens who are actively engaged in protecting and preserving our river. By sharing information and working together we are doing everything we can to ensure we leave a healthy river and lake for future generations to enjoy.