What They Are Doing Now

* Master of Science, 2012, University of Guelph

Advisor: Professor Richard D. Moccia


Application of a lake-wide nutrient mass balance model to a freshwater lake with cage-aquaculture on Manitoulin Island, Ontario.


Aquaculture is one of the fastest growing food producing industries in the world. In Canada, there were 6598 licensed operations in 2004. Every province, and the Yukon Territory, has an aquaculture industry. In Ontario, the Great Lakes provide a potential opportunity for growth in the fresh water sector: however, at present, perceived environmental impacts are influencing growth of this industry. From an environmental perspective, one of the main concerns in Ontario is eutrophication. Soluble Reactive Phosphorus (SRP) is of particular concern in phosphorus  limited lakes such as Lake Huron and Georgian Bay because excess SRP can lead to extensive algal blooms and decreased dissolved oxygen. Total phosphorus (TP) includes the particulate and the soluble forms derived from waste feed and fish feces, as well as plant and other animal organic matter.

Given the current risk management policy in Ontario for surface water quality, inherent issues or “science gaps” arise. At present, the assessment of these sites is based on in-situ samples, meaning results are based on phosphorus concentrations at the particular time of measurement.  Because nutrient loadings can be dynamic, the need for a predictive tool is of utmost importance to more accurately assess any current or future problems that may arise on a lake-wide basis. A nutrient mass balance approach will be implemented on a fresh water lake in Ontario with a working cage-aquaculture farm to predict current and future contributions of nutrient loading and assimilative capacity. This study is on-going and will be completed in 2010.