A Weed Eating Fish

Derick Keet - stocking Tilapia at a test site - Summer '92

by Hans G. Peterson, Saskatchewan Research Council, Saskatoon, Saskatchewan

Tilapia, a tropical fish, is being considered as an alternative to chemical weed control. Requiring a lot of vegetables in its diet, Tilapia will eat lettuce, but doesn't care much for Swiss Chard! When put in a prairie dugout, it will eat all kinds of weeds. Green algae that grow like shoestrings around the sides of the dugout can be consumed at a rate equal to the fish's own body weight per day. Tilapia will more than double its weight during three months in a prairie dugout.

Tilapia will only survive in prairie dugouts when the water temperature is warmer than 8¯C. Dugouts, therefore, need to be stocked in June and harvested in late August-early September. Fresh Tilapia is considered a delicacy in most places where it is available.

(Courtesy Regina Leader Post - Don Healy)

D & J Keet Inc., (Vanscoy, Saskatchewan) hopes to make this fish available across the prairies in the next couple of years. D & J Keet Inc., in collaboration with Saskatchewan Research Council (SRC) and Napier University (Edinburgh, Scotland), is working with federal and provincial government agencies across the Canadian prairies to determine the benefits of Tilapia as an ecologically friendly weed control method.

Funds for this research have been provided by the National Research Council (NRC), the City of Regina, and the City of Saskatoon. The above organizations have also supported other non-traditional algae and weed control methods in city dugouts (urban lakes used for stormwater storage and diversion).

Weed and algae control are, however, not the only concerns in water management and the effect of Tilapia on other water quality factors will be researched during 1993.