Fed. court rejects Asian carp lawsuit

Dr. Gerald Smith, fish biologist from University of Michigan explained why there is NOT an immediate risk from the Asian Carp on this podcast: http://www.miskeptics.org/2010/10/carpe-carpem-episode-two-of-the-drunken-skeptics-podcast/

The four points that Dr. Smith raised regarding the actual science behind the Asian Carp threat that resonated with me were the following:

1) Asian Carp (like its already here cousins, the Common Carp) can only survive in warmer waters (about 1% of the total Great Lakes). The commercial fishing industry won’t be affected by the Asian Carp because it utilizes the deeper, colder waters. Another point that Dr. Smith raised that may not have been emphasized enough were that studies suggesting Asian Carp would be acclimated to the Great Lakes utilize air temperatures, not water temperatures. Although, I’ve not been able to get my hands on these studies, which is why we didn’t emphasize it in the post-interview discussion.

2) The diet of Asian Carp is phytoplankton, which its numbers are way down already because of the zebra and quagga mussels. Therefore, they will have strong competition for the same food as two other already-thriving organisms.

3) In the areas that Asian Carp would flourish (again, about 1% of the Great Lakes), they would experience heavy predation. And many of its predators are already desperate for food – so its possible that Asian Carp would help rejuvenate other fish stock as its eggs and young would be another food source for hungry predators.

4) If Asian Carp get into rivers, they would need long stretches of water that have no dams – for spawning. However, most rivers in Michigan have dams which would make reproductive success very challenging.

Sounds like Dr. Smith is lost in space and has forgotten that many warm-water species have adapted to Great Lakes related waters. Carp, bass, suckers and others are all species that thrive in warm waters but are doing well throughout the Great Lakes system. Check out west bay of Traverse City. Great carp pops there. If these species are experiencing “heavy predation” why are they doing so well? If they aren’t experiencing “heavy predation” why not? What makes them different from Asian Carp? Further, asian carp grow much more rapidly than the predators and in a short time reach a size that make it impossible for the predators to eat them. As for the phytoplankton, it may be a limiting factor in the big lakes but not the rivers and streams. The dam argument fails because the dams are not at the mouth of the river but many miles inland. Thus, what he is saying is that it is okay to let asian carp take control of that section of the river. (Check out the Muskegon). That would produce two harmful results: (1) crowding out of trout species in those areas and, (2) it would create a disincentive to removing the dams. Many dams in Michigan are aging and will be removed in the future to establish a connection between the two habitats and open up entire river systems to spawning for trout and salmond species. Dams cannot be figured into the equation.