Water transferred from Devils Lake poses a low risk to downstream fish and fisheries, the International Joint Commission announced today.
Results of a three-year study, Devils Lake-Red River Basin Fish Parasite and Pathogen Project, Qualitative Risk Assessment, indicate that three bacteria, one parasite, and several lesions identified in fish from Devils Lake are not found elsewhere in the basin.
An expert panel of pathologists determined that they could be transferred downstream through a number of pathways, including an existing outlet with gravel and rock filter, by birds, bait transfer by anglers or boats moved from one location to another.
However, the panel also concluded that the parasite and bacteria in question generally are widely distributed throughout much of North America, and that none are foreign species and that they could have an adverse effect on fish health only if it was already compromised for other reasons.
"For these reasons, all the experts concluded that the risk to downstream fish and fisheries from the parasites and pathogens of Devils Lake is low, and the potential for causing disease is minimal," the IJC said in its report.
ADVERTISEMENT
Water transfer
The U.S. and Canadian governments requested the study in 2005. It was conducted by the IJC's aquatic ecosystem committee for the International Red River Board.
According to 2005 statistics, the Devils Lake sport fishery and recreational industry was valued at $56 million annually, while the Red River recreational fishery in Canada was estimated at $10 million to $15 million annually, while Lake Winnipeg's commercial fishery, the largest in North America, had annual revenues of more than $15 million.
The state of North Dakota began transferring water downstream from Devils Lake in 2005 through an outlet to the Sheyenne River. While it has been expanded to a capacity of up to 250 cubic feet of water per second during the summer and fall, mechanical problems this year have resulted in average releases of about 100 cfs or less.
Devils Lake has risen by nearly 32 feet and quadrupled in size since 1992, hitting a record elevation this summer of 1,454.4 feet above sea level, less than four feet below the point at which it would begin overflowing from the connected Stump Lake to the Sheyenne.
By next summer, the state plans to build two additional outlets and a control structure, increasing the potential transfer to as much as 1,000 cfs.
Study suggestions
The IJC's study included six recommendations:
ADVERTISEMENT
- Adopt a precautionary approach to monitoring and preventing the transfer of invasive species and certain fish pathogens into the Hudson Bay Basin.
- Use data from the present study to assess the risk to fish in the Red River Basin from parasites and pathogens found throughout the basin, including Lake Winnipeg. Use innovative risk analysis methods and techniques such as computer modeling.
- Establish a program to monitor fish parasites and pathogens.
- Start a project to determine route of transfer, rate of spread, and distribution of the Asian tapeworm in the Hudson Bay Basin. The population characteristics of the tapeworm could be used as a model to study invasion pathways of foreign species into the watershed.
The IJC was established by the Boundary Waters Treaty of 1909 as an independent adviser to U.S. and Canadian governments. More information, including the full report, is available at: www.ijc.org.
Reach Bonham at (701) 780-1110; (800) 477-6572, ext. 110; or send email to kbonham@gfherald.com .
