Predator bass could reach Fraser River

Smallmouth bass continue to be a problem

  • Sep. 9, 2011 6:00 a.m.

The smallmouth bass continue to be a cause for big concern for regional and provincial governments and residents who live around water systems where the fish have taken hold.

The fish were first discovered in the Beaver Valley system in 2006; in 2010, a few were found in Big Lake. In a recent letter from the Ministry of Forest, Land and Natural Resource Operations to the Cariboo Regional District there is a suggestion that the bass are “… moving freely downstream into the Quesnel River and possibly into the Fraser River.”

Roger Stewart, director of resource management for the Cariboo region for the ministry, says the fish are in all of the lakes of the Beaver Valley chain and Big Lake.

It is believed that the bass in Big Lake are a more recent phenomena and Stewart says the ministry is unsure of how long they have been there or who put them there.

Stewart is concerned about where the bass could move next.

“Because the bass exist in all those reaches of the Beaver Valley system there’s nothing that prevents them from migrating out the bottom of Beaver Creek and into the Quesnel River system,” he said.

“Once into the Quesnel (system) we are uncertain about their survivability – if they develop a base of representation in the Quesnel and then, of course, from there they can move into the Fraser and can populate downstream from there.”

The concern around the presence of smallmouth bass in the system is the species is a fish predator. Stewart says in its juvenile stage the fish feed on the same food as young trout and salmon, and as it grows it becomes a predator.

“They out-compete at the very early life stages and they predate effectively in their later life stages and they are relatively long lived as well,” he said, adding the fish are also highly reproductive.

“Bass can survive in far greater or variable conditions than the salmon can and, as a result from an ecological context, out-compete other species at the expense of fish populations that are at the core of our recreation, our economy and our First Nations cultural heritage.”

Stewart says the ministry hasn’t yet seen an effect of the bass on salmon stocks but says that could simply be a feature of the “rigorous” chinook, sockeye and coho populations.

The ministry has undertaken mitigation measures such as public education and erecting barriers but says the only way to ensure eradication of the bass is the use of a chemical known as rotenone, a product derived from a plant of the legume family that is fatal to aquatic species with gills.

Stewart acknowledges there remains a split amongst the population regarding the use of the chemical that will kill gill-breathing animals in a lake system. He says the use of rotenone is expensive, would result in the death of gill-breathing species, and the subsequent restocking of species.

“There are those who abhor any attempt that we might do to have such an impact on the ecosystem as to undertake an eradication program,” he said.

“It’s a difficult proposition but it’s far more palatable than allowing a bass population to live in our midst and to have people continue to carry them to other lakes.”

Stewart said there is an example of a successful application of the chemical in the Thompson-Okanagan region and the subsequent rebuilding of the lake population.

He agrees there needs to be a broad public acceptance of the procedure and that hasn’t occurred in the Cariboo yet.

Joan Sorley, a former member of the Big Lake Community Association and resident of the area, says that bass in Big Lake would be devastating for the community as it relies on the lake as an economic driver and for a large community fishing derby fundraiser each year.

At the same time the community is split on the use of rotenone.

“There are mixed emotions about that,” she said.

“Poisoning isn’t necessarily embraced.”

Sorley said if the ministry manages to find money to apply the chemical then the community will have to decide if it will let rotenone be used.

She adds it’s a concern if the bass are migrating downstream and potentially impacting salmon.

As the Area F director for the Cariboo Regional District Sorley added that at its recent meeting the regional district requested more details on the movement of the bass and asked for a greater commitment to public education.

Currently the ministry is seeking funding for the use of rotenone. While it has the money to develop an eradication plan — that could be developed by March 2012 — there is not enough funds to carry out the eradication work.

In a letter from the ministry to the CRD the ministry notes that “… under current economic conditions, we face an intractable problem in allocating sufficient financial resources to eradicate this infestation.”

It is believed the fish in both Beaver Lake and Big Lake were carried illegally to those water bodies and the investigation into that is ongoing.


Quesnel Cariboo Observer