Tuesday, January 24, 2006

The Right Fisher Model?

Alewife, good or bad, invasive or not? As reported by the Chicago Tribune, it may depend on how you look at it. Turns out the alewife (Alosa pseudoharengus) has been sustaining stocked populations of salmon in Lake Michigan, and those stocked populations have been sustaining a thriving sport fishery. The coho and chinook salmon (Oncorhynchus kisutch and O. tshawytscha, respectively) were first stocked in the lake in the 1960s as a way of controlling the non-native alewife, whose populations had grown out of control. Now the salmon have developed a taste for the alewife, and they've practically eaten their invasive food supply out of existence in the lake. The Michigan Department of Natural Resources is responding by cutting back on the number of salmon that will be stocked in the spring, in order to give the alewife a chance to recover.

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