Wednesday, March 2, 2011

Lansing High Brook Trout

The growth of the brook trout popoulation and their interactions are an interesting topic to study. When the eggs first hatched, there was more than a hundred of the young trout. However, as they grew, their population went down.
When counting the population of the fish in the tank, we ran into some trouble. Although it sounds strange to have trouble counting fish, we found that the fish blend in to the rocks used at the bottom. At first we tried to count from left to right as fast as we could. It was a practical method, but wasn't working because the trout would swim around, making us unsure of what fish we had counted and what fish had not been counted. To try and counteract this, we put food in the water to try and get the fish to swim to the top and eat while we counted. This technique didn't have very much success as the fish would swim to the top one or two at a time, seeing as how all the fish didn't realize that food had been put into the tank. This method of counting was also unsuccesful because the fish became more agitated when food was put in and they moved around more, making it more difficult to count them. One method that we may try in the future is to take a picture of the fish and then count them all.
About two weeks ago Mr. Foster came into our school to feed our fish daphnia. About six kids came after school and we watched a very interesting powerpoint about daphnia. Before we watched it we isolated three fish into 3 seperate beakers and put blue paper around each beaker to soothe them. After we watched the powerpoint, we took the blue paper off and inserted some daphnia. Our fish shied away form the daphnia and did not eat many of them. The fish that I was watching only ate one Daphnia. The fish actually appeared to be marking its territory at one point. It swum around half of the beaker repetitively. We believe it is a possibility that the fish would have eaten more if we had put a rock or something to shelter them inside their cage because it would provide a more natural and safe feeling habitat.

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