In reply to Dr. Muir [6 September]:
No, obviously we have not examined 2,995,730 fish, but I fail to see the point. If it is essential to confirm that every individual fish within a population is sterile, then it is a simple matter of testing every individual fish within that population before it leaves a secure facility. This is not without precedent: there was a time when every individual grass carp released for aquatic weed control in some US States had to be confirmed triploid before its release.
Tillmann J. Benfey, PhD
Professor and Director of Graduate Studies
Department of Biology, University of New Brunswick
Fredericton, New Brunswick E3B 6E1, Canada
tel (506) 453-4583; fax (506) 453-3583
http://www.unb.ca/web/biology/Faculty/Benfey.html
e-mail: benfey@unb.ca
[To contribute to this conference, send your message to biotech-room4@mailserv.fao.org For further information on the FAO Electronic Forum on Biotechnology in Food and Agriculture see http://www.fao.org/biotech/forum.asp ]
-----Original Message-----
From: Biotech-Mod4
Sent: Thursday, September 07, 2000 4:55 PM
To: 'biotech-room4@mailserv.fao.org'
Subject: Re: Sterility techniques
I totally agree with Dr. Benfey's suggestion [7 September] that every transgenic salmon be tested for sterility before rearing in net pens. This potentially reduced [reduces ?..Moderator] the risk to below that of commercially raised domesticated salmon. The need for this precaution and potential failure is emphasized by his reference to grass carp. Grass carp are a prime example of what can go wrong.
See Loch and Bonar, Transactions of the American Fisheries Society 128: (2) 374-379 1999 who observed forty-nine adult grass carp migrating upriver past lower Columbia and Snake river hydroelectric dams between August I, 1996, and September 30, 1997. They conclude that "although the source of these fish is unknown, their appearance in the Columbia and Snake rivers might have been related to extensive flooding that occurred in western Washington and Oregon in February 1996. The unintentional escape of grass carp into this large river system re-emphasizes the need for the current requirement that all grass carp stocked in Pacific Northwest lakes be sterile triploids. It also suggests that increased attention to effective barrier construction and maintenance is important to prevent grass carp impacts in nontarget areas."
Also see Elder and Murphy, Journal of Freshwater Ecology 12: (2) 281-289 1997 who confirmed grass carp spawning in the river systems entering Galveston Bay and conclude this is a serious concern to many fisheries ecologists. "Researchers suspect a portion of recent losses in submersed vegetation and marsh habitat in Galveston Bay may be due to the presence of grass carp. Grass carp captured in the Trinity River were examined to determine population structure, ploidy, fecundity, and diet. Fish captured were primarily diploids and represented a broad range of cohorts, providing strong evidence that naturally spawned grass carp are being recruited to adult sizes in the Trinity River."
Everywhere grass carp have been observed in non-native ecosystems, they have caused ecological damage and elimination of some competing and non-competing species, even causing problems for migrating birds. How is it that a known environmental hazard has invaded our ecosystems given the precautions that were taken? Is this a page from history that may also apply to "triploid" Atlantic Salmon?
Bill Muir
Professor of Genetics
Department of Animal Sciences
Purdue University
W. Lafayette, IN 47907-1151, USA
Phone 765-494-8032
FAX 765-494-9346
E-mail Bmuir@purdue.edu
http://www.ansc.purdue.edu/faculty/muir.htm
[To contribute to this conference, send your message to biotech-room4@mailserv.fao.org For further information on the FAO Electronic Forum on Biotechnology in Food and Agriculture see http://www.fao.org/biotech/forum.asp ]