California Wild Summer 2002 - Letters to the Editor

The Magazine of the CALIFORNIA ACADEMY OF SCIENCES

Letters to the Editor

Good and Bad Shellfish

I was pleased to see that John McCosker’s reference guide (Winter 2002) recognizes that “bad fish” and “good fish” may be determined by the type of aquaculture practice. For example, oysters may be a sustainable industry in some places, but they are decidedly a problem in Humboldt Bay, California, where they are responsible for the destruction of eelgrass beds. Eelgrass provides an important nursery for groundfish, herring, crabs, and many other commercially important species. When oysters are dredged, the eelgrass is removed. Oysters grown on longlines also impact the eelgrass beds by increasing the sediment deposition, which raises the bed elevation until eelgrass can no longer grow. While oysters may help keep waters clean, farming practices of oyster companies are important in determining whether or not oysters are a sustainable fishery.

Christine Ambrose
Arcata, California

Good and Bad Fish Farms

The article “The Catch to the Catch of the Day” is making the rounds of fly fishing boards. Before repeating or commenting on your noting of damage being done by the farming of Atlantic salmon, I am wondering if the author has a bibliography of peer-reviewed articles documenting the cases of disease causation to local, non-penned stocks by this practice. I am especially interested in data of any actual genetic exchange with local stocks.

I am just a retired scientist who likes to see strong comments documented.

Fred Rickson
Tucson, Arizona

John McCosker responds: I too am trained in science and appreciate the difference between peer-reviewed journals and the vast amount of gray literature that exists, particularly as concerns such contentious and ecologically sensitive issues as salmon farming. You, as a scientist, are also able to appreciate the time between data collection and analysis, submission, and final publication in journals—a lot of this is happening very quickly around the world. Having said that, I have been working on salmon in the North Pacific for more than a decade and have visited and fished in Kamchatka, Alaska, British Columbia, Cascadia, California, Iceland, and Siberia for many years, and have seen dramatic changes in salmon populations in many of those areas. This is due to a variety of insults, including, in many cases, the practice of pen-rearing salmon. I have not personally observed the causes of the salmon collapse in eastern Norway but suggest that you contact the Atlantic Salmon Federation. The following are some references from peer-reviewed journals. I have a longer list for anyone who wishes it.

Devlin, R. H. 2001. “Growth of domesticated transgenic fish.” Nature 409: 781-782.

Fleming, I. A. and S. Einum. 1997. “Experimental tests of genetic divergence of farmed from wild Atlantic salmon due to domestication.” ICES J. Mar. Sci. 54: 1051-1063.

Hedrick, P. W. 2001. “Invasion of transgenes from salmon or other genetically modified organisms into natural populations.” Can. J. Fish. Aquatic Sci. 58: 841-844.

Kapuscinski, A. R. and D. J. Brister. 2001. Genetic impacts of aquaculture. In Environ. Impacts of Aquaculture. UK, Sheffield, Academic Press.

McGinnity, P. et al. 1997. “Genetic impact of escaped farmed Atlantic salmon on native populations.” ICES J. Mar. Sci. 54: 998-1008.

Muir, W. M. and R. D. Howard. 1999. “Possible ecological risks of transgenic organism release when transgenes affect mating success: sexual selection and the Trojan gene hypothesis” Proc. Nat. Acad. Sci. 96: 13853-13856.

Utter, F. 1998. “Genetic problems of hatchery-reared progeny released into the wild, and how to deal with them.” Bull. Mar. Sci. 62: 623-640.

Volpe, J. P. et al. 2000. “Evidence of natural reproduction of aquaculture-escaped Atlantic salmon in a coastal British Columbia river.” Conserv. Bio. 14: 899-903.