Addressing Concerns for Water Quality Impacts
from Large-Scale Great Lakes Aquaculture

Based on a Roundtable
Co-hosted by the Habitat Advisory Board of the Great Lakes Fishery Commission
the Great Lakes Water Quality Board of the International Joint Commission

August, 1999


The January 27-28, 1999 roundtable discussion of water quality impacts of Great Lakes aquaculture raised awareness of a timely issue and facilitated discussion among representatives from government, academia, industry, First Nations, and environmental nongovernment organizations (Appendix 2). Water quality impacts due to State hatchery operations have been documented in Michigan's Big Platte Lake (i.e., elevated phosphorus levels, increased primary productivity, reduced water transparency). In addition, water quality impacts due to caged aquaculture have been documented in Minnesota lakes (i.e., approximately an order of magnitude increase in water column phosphorus, nitrogen, and chlorophyll levels, and increased attached algal growth) and in one case in Ontario on the North Channel and Georgian Bay of Lake Huron (i.e., elevated phosphorus levels, reduced water transparency, algal blooms, and dissolved oxygen depletion over 250 ha). Industry representatives provided information that other operations in Georgian Bay have been well managed and have not resulted in any substantial water quality problems (Appendix 12). It was generally felt that water quality problems can be substantially prevented with better assessment, siting, prediction of carrying capacity, and management of food and fish.

Caged aquaculture operations in the Great Lakes are currently limited by available technology and suitable sites, and neither caged nor land-based aquaculture is expected to grow substantially. The aquaculture industry is interested in achieving economically-viable and environmentally-sustainable operations. Both the aquaculture industry and governments want to limit water quality and habitat impacts.

One promising analytical tool, sponsored by the Great Lakes Fishery Commission, is being developed to help prevent water quality impacts from aquaculture and prevent introductions of exotic species. This decision support system titled "Environmental Assessment Tool for Private Aquaculture in the Great Lakes Basin" is being developed by the University of Minnesota (Appendix 13). This user-friendly, computer-based system is designed to help direct impact assessments and guide risk management decisions regarding aquaculture operations.

Based on a review of the information and discussions from the roundtable, and the extended abstracts presented in this report, the roundtable steering committee has made the following recommendations:

To governments it is recommended that:

To the Great Lakes Fishery Commission and the International Joint Commission it is recommended that they:

To government agencies, universities, and the Commissions it is recommended that the following research needs be addressed:

To the aquaculture industry it is recommended that: