in Lake Michigan (Long, 2001). These crustacea, are half made up of fat, and are an important link in the food chain, being consumed by many fish at some stage in their life, and as late as the 1980s they swarmed as dense as 10,000 per square yard of lake bottom. These quarter-inch creatures are an important food energy source for many kinds of fish, including bloater, alefish and sculpin, which, in turn, are eaten by trout and salmon. Whitefish are also suffering the loss of the diporeia. For a given length, fishermen report, they don't weigh as much as they should. With the decrease in prey fish, it is feared that the loss of trout and salmon, which are big money fish, may have serious economic effects. Although the link is not yet proven, the disappearance of the diporeia began in the 1980s, around the time of the appearance of the zebra mussels. Zebra mussels take in water to eat, filtering out all the tiny particles and eating what is suitable. The rest they spit out as pseudofeces. Scientists
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