Lake Wabamun : a review of scientific studies and environmental impacts /

The following recommendations are in roughly descending order of importance: The parties who would implement these recommendations are not identified in this report since the Panel assumes that responsibility for implementation would be allocated according to a combination of current government agency mandates and activities, industry permit requirements, and input from citizen or scientific advisory groups (see final recommendation). FisheriesDespite heavy recreational activity and industrial use.Lake Wabamun is in moderately good condition.The most serious problem is with the fish community.As a result of commercial fishing, sport overfishing, and destruction of fish habitat, walleye have disappeared from the lake.Few pike survive long enough to reach reproductive age.Lake whitefish have not successfully reproduced for several years.• We recommend that commercial fishing be eliminated altogether, and that sport fishing be restricted to catch and release until populations recover to more normal age structures.Past efforts to re-introduce walleye have been unsuccessful.High hooking mortality from catch and release angling is probably responsible.• We recommend that any future attempts to reintroduce walleye be accompanied by total closure to angling of areas of the lake where walleye congregate, until several age classes are established.While great efforts have been made to reduce industry-related fish mortalities, they are still significant and in some cases unpredictable in occurrence.They are, however less important than mortalities caused by angling or commercial fishing.• We recommend continued vigilance to prevent and correct fish mortalities.These mortalities should also be taken into account in management and allocation of the fisheries resource.Weed harvesting is a relatively insignificant source of direct fish mortality, but it causes a significant loss of fish habitat.Modifications of shoreline properties by cottagers have also resulted in significant loss of fish habitat.• We recommend that weed harvesting be discontinued, and that other prohibited destruction of fish habitat, including weedbeds, be monitored and enforced according to the Canada Fisheries Act.Dredgings Disinfection By-products and Thermal Effluents We found that these three topics required no action, for a variety of reasons.Dredging does not appear to be likely to provide significant benefits to the lake.It would require lengthy and thorough investigations to ensure that fish habitat was not destroyed.• We do not recommend dredging at this time.Disinfection by-product concentrations for the Wabamun Lake Water Treatment Plant are low, and below thresholds where effects on human or animal health would be expected.Although little is know about effects on aquatic life, concentrations in the discharge are low and vastly diluted by the volume of the lake.• Disinfection by-products are not of concern.The thermal effluent from the Wabamun Power Plant will cease as the Plant is decommissioned.Appropriate measures have been taken to mitigate the effects of the thermal effluents.However, the loss of the open water region of the lake in winter after the thermal effluent ceases may result in possible oxygen depletion under ice.• We recommend that follow-up studies should investigate the possibility that oxygen depletion under winter ice might occur after heated effluents cease. Additional RecommendationsMany of the past studies of Wabamun Lake have been undertaken by Alberta Environment staff or by consultants hired by TransAlta in response to public perception.Some of the perceptions did not justify scientific study, and some other issues were simply not amenable to scientific investigation.Examples include disinfection by-products and dredging.At present, there are several stakeholder groups that independently pressure Alberta Environment or TransAlta with their own interests.• We recommend that a permanent citizens panel, whose objective it is to protect the health of Wabamun Lake, needs to be established and maintained.This panel must have members who are selected by, and representative of, the community of Wabamun Lake users.Representatives of various interest groups, as well as TransAlta and government agencies should also be included in the membership.A parallel scientific panel, consisting largely of independent scientists but including representation from Alberta Environment and TransAlta should be formed to advise the citizens' panel on the scientific value of any proposed studies.

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