Changing the community structure in an unbalanced multi-species fishery in 50 acres is a very daunting task. IMO experienced professional fishery managers are usually needed for best chances of good end results for a project of this size, and even then the fishes often do not co-operate as planned or hoped. Each fish species and each individual fish present has participated in one way or another in creating the current condition of the fishery. This is where management experience and knowledge with all the species involved becomes more important to have a better chance of achieving desired results.
Numerous management methods and 'tools' could be used to gradually guide this multi-species fish community toward a desired goal. In my experience the manager does not have to just manipulate the fish density but also he/she should be able to evaluate the amount and types of habitat, the standing crop, the recruitment success of each fish species, and the limnology of the whole ecosystem because everything in the entire lake is interconnected and functions together as a unit. The whole system functioning together has contributed to the current condition of the fishery. First knowing or evaluating the lake productivity, carrying capacity and standing crop of species present will be important IMO toward knowing how many and what specie of fish that should be removed annually. As I mentioned the larger the system and the more species that are present,,, the more complex the project becomes because all participants of all plant types, various water components, invertebrate populations and fish species and as individuals are ecologically interconnected one way or another that determines the food web of the lake. Change one integral part and it often has some sort of affect on the food web. Thus it helps a lot to know how these systems all function together to better anticipate, or evaluate the change and be prepared to deal with the changes that happen.
Again larger waters for good management efforts need larger amounts of reliable, experienced participants, and a regular amount of effort to get the desired major changes to happen. I expect achieving some of the desired goals will take time; conscious effort, and probably several or even numerous fish generations. Again IMO it will be a daunting task to achieve good results. The more species present and the larger the water body the more difficult the project becomes. Knowledge and experience with knowing the feeding levels of all involved species helps for better chances of creating the desired change. The larger a water body is,, the more complex it becomes as an ecological dynamic and constantly changing system. It involves many more involved parts than just one or two species of predator.
The larger the water body is the more man hour effort it will take to remove enough individuals to make noticeable and measurable population adjustments. Ideally IMO first knowing about the whole fishery involving all the species populations and how they interact should be determined, assessed, total numbers evaluated including carrying capacity and standing crop, and then what adjustments should be attempted toward the desired end goal. During the process as changes are made, one should be capable of evaluating how the entire fishery is responding to then better estimate if improvements are being effective. As an example, the size of this water body and project involved often requires several pro-DNR employees to get a project like this accomplished and even then sometimes their combined efforts are thwarted by Mother Nature.
At this time adding more fish species to the existing fishery I don't think is a good idea without first getting some professional advice from experience because a new fish specie complicates the interactions of all the fish present and makes achieving the desired goal more complex and difficult. Adding more species to a 0.5 to 1 ac pond has a lot fewer implications than adding more species to a 50 ac body of water.
Last edited by Bill Cody; 08/05/22 10:25 PM.
