Thursday, January 31, 2013

River dams: good for generating electricity but bad for fish. In the Northeast US, many ocean fish species swim into rivers and upstream into small tributaries to spawn -- and complete their life cycle. Dams are a major barrier to these migratory fish and so people have come up with a variety of ways to help get fish around the dams -- from trapping and trucking to structures called fish ladders and elevators. 

For ScienceNOW, I wrote about a new report that looked at the numbers of fish using fish passages on three major river systems: the Merrimack, the Connecticut, and the Susquehanna.  Although stated targets at these dams call for hundreds of thousands of fish to pass through, the actual numbers were in the hundreds, the tens, and in the case of river herring on the Susquehanna, single digits. 

The report's authors make their case for dam removal, saying that other dams -- farther upstream or on less ecologically important waterways -- could make up the power loss. Further they point to Maine, where such radical action has been taken on the Penobscot River. 
photo credit: Wildcat Dunny on flickr

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