Monday, January 10, 2011

Saginaw Bay Watershed blocked by dams

Fish Passage

The Saginaw Bay watershed is fragmented by nearly 300 dams or spillways . Improving fish passage at existing dams, either by ladders or by dam removal is the single surest means with which to increase natural reproduction. River spawning walleyes are already abundant in the bay, and are the only proven source of natural recruitment.  Establishment of fish passage and/or removal of unnecessary dams, while no small undertaking, can pay great dividends in terms of enhancing walleye recruitment. Enhancement of fish passage will also benefit lake sturgeon, white bass, and a variety of other warm water species. 

Figure 1. Saginaw Bay watershed. Dots indicate the location of a dam or spillway obstacle.

Dam removal is the preferred option for maximizing the benefits of natural reproduction. Dam removal eliminates the problem of safe and effective downstream transport of walleye fry which may otherwise be retained above dams or killed in hydroelectric turbines. Removal of dams also facilitates recovery of high gradient river reaches which are often necessary for successful natural reproduction.

Saginaw Bay's fishery is already valued at well over $18,000,000 in the 1990's 
and accounts for 58% of the total sport fishing effort on the Michigan waters of Lake Huron.

Excerpt taken from :
Strategy and Options for Completing the Recovery of Walleye in Saginaw Bay
David G. Fielder
Michigan Department of Natural Resources
Fisheries Division
Lake Huron Basin Team
August 2002

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