Some Thoughts on the Bonaparte Plateau Fishery, from the perspective of the sport fishing industry.
In lakes with Squaw Fish populations challenging the Squaw Fish population worked, there was a marked improvement in size of fish in a couple years after the process started. The challenge remains however, that the traps only get a portion of the population, even once we trapped, I still saw them “balling” up in large numbers. I believe this is the portion of the population that “shore spawns”, apparently they are prolific. I know people who have had success with “spot” applications of Rotenone, when one sees the fish “balling up”, applying Rotenone to the surface kills a major portion of the population – it ends up being targeted and with very little damage to the overall biology of the lake, in contrast to typical applications of Rotenone. There was an old time operator on in the area, who shall remain unnamed, who enjoyed success with this process; he also would wait until the creeks were full of squaw fish in the spring, with few trout, and used the same technique.
It is an interesting outcome that in using triploids, that the fish population in the mixed specie test lakes decreased in size and quality after the introduction of the triploids. This in conjunction with the pure culture Lake reality which had triploids gaining in size rapidly in a pure culture lake, makes for some interesting contemplation. It maybe the mix specie situation is a product of other fish management stopping, trapping, slot limit and the like. Blackwaters, while piscivorous fish, eat insects; it maybe that they are just eating insects and leaving the Squaw Fish unfettered; reflecting on the pure lake circumstance of rapid growth of the triploid fish stocks.
The thing that seems to be missing in the management of fish by the government, is what ranchers lay awake at night thinking about, how to make livestock bigger – like begets like bible says. So at the risk of oversimplifying, if you kill the big ones, the little ones breed. Like my animal science mentor use to say, “select for what you want and cull what you want to avoid”. In the context of a pure culture lake, slot limits are likely to work because you take the immature fish and the small, the larger fish have opportunity to mate. I believe this to be true of the mixed culture test lake, there was a marked improvement in size of fish after the trapping program – and if my memory serves – another improvement after the slot limit was used. The mixed culture test lake having a Squaw Fish infestation adds to the complexity of assessing this challenge, culling what you want to avoid begins to have a broader application.
If there were a way to select for larger fish and introduce them to the population, from a “sport fishing” perspective you would enjoy better success. The fish breeding management for sport fishing's “end in mind” is to have really big, dumb, hungry and angry fish.
As I know many aware, XXXXXX Lake is likely the best fishery on the Bonaparte Plateau. There is commonality in weed specie types between XXXXXX and the very productive lakes south of Kamloops. There can be a number of contributing factors affecting weed species, one I think may hold prominence is PH. I am unsure what the optimum weed specie complex is and what PH contributes to the complex, I do know however, lakes in areas with PH nearing Alkali tend to be more productive. The plateau lakes are more acidic, as is characterized by the tea coloured water, Lilly pads and the like. It is on this basis that I would contemplate liming the lake in winter by applying lime to the ice as late in the winter as possible. My observations support this as a course of action. It is interesting also that there has been a generalized degradation in fishery since the “bug Killed” pine have shed their needles (acid in nature) - it seems possible this could be a part of the complex of influencing factors.
There is likely merit also in fertilizing key weed beds. Having altered the PH,spurring the growth of plant species conducive to a richer aquatic ecosphere, it seems rational to encourage growth, the mixed culture test lake, as is the case in many of the lakes up there, is “undernourished” from the viewpoint of optimizing the fishery.
I hate to be critical of the present choice to maintain a catch and release fishery, while counter intuitive, taking trout improves the overall experience, especially if it is done with care – slot limits and the like. It seems the experience with the mixed culture test lake is supporting this. On the pure culture lakes this is especially true, they really do need some fish taken. XXXXXX may be one exception, although, a slot limit would likely be okay. I share the view, that the data from stomach contents is critical as well.
This is some preliminary thinking, there would a little work to do before executing.