| | Fish did not fare well in some farm ponds during last winter. Winterkill was prevalent across the province. The ice formed on ponds at the usual time but the snow fell early and melted late. Where aeration was not provided many fish died.
So far, this winter looks good for fish in ponds and dugouts. Although the water has cooled down normally, ice cover came late. Fall winds kept the pond water well mixed and aerated. Lots of oxygen was available for the decay of algae and other organisms that died and fell to the bottom over the summer. Not everything has decayed but there was a good start while oxygen from the air was still available.
Now that ponds have frozen over, watch the amount of snow on your fish pond. The depth of snow cover will play an important role in determining how well your fish survive the winter. When there is little or no snow on the ice, sunlight can pass through the ice and into the water where it stimulates photosynthesis by the microscopic algae. Through photosynthesis the plants release oxygen into the water.
With little snow, photosynthesis continues and oxygen levels remain high. However, once the snow gets more than a few inches thick, light penetration is blocked and oxygen levels start to drop. When oxygen levels drop to below 4 milligrams per liter, some fish die.
One thing you can do to keep photosynthesis going, and to help your fish through the winter is to clear the snow off a strip of ice 5 to 6 meters wide along the north side of your pond. The strip you clear should be about 6 meters from the shore so that the sunlight penetrates the water. For more information on aeration, contact Eric Hutchings, Provincial Aquaclture Specialist, AAFRD, Lethbridge at (403) 381-5574 |
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