So, why write a post today? Simply put, I'm writing because I've been impressed. Impressed with the time, effort and great biology that goes into our state's fisheries management. I'm not claiming them to be perfect, but I think they really do as best they can with the resources they're given.
A great tool that the division has developed, not only for their implementation but also for helping the general public understand their decisions, is their "A Simple Four Step Method to Manage for Quality Fishing" (read it for yourself here). We'll be going through this method over the next few posts, so here we'll just look at the first couple methods.
1) Inventory Current Status with a Standard "Yardstick"
Now, if you look up info on some famous tailwater fishery they'll talk about fish per mile (and yes, we're all very impressed) but in order to not favor the larger rivers and instead find a level playing field the "Yardstick" used is the "pounds of fish per acre" measurement. You can take the pounds per acre measurement and compare rivers and streams across the west and come out with useable comparisons. The average stream across the west has about 50 pounds of fish per acre, while better streams have better than 100 pounds. A great stream would have between 300 and 400, while some crazy extreme cases have closer to 1,000 pounds though this is not the norm and usually not sustainable.
2) The Magic of Population Density and Fish Size
So, when you look at the first method you think "How can we increase the pounds per acre?", but through method 2 we learn that increasing pounds per acre isn't necessarily a viable option. Remember this isn't "fish per mile" where an increase is more fish, but this is pounds per acre. Meaning that there may be 50 pounds per acre, but it consists of 50 one pound fish. Most would agree that this isn't an ideal situation. Taking the same bucket capacity of 50 pounds per acre, we could potentially have only one fish at 50 pounds, which isn't necessarily a viable population either.
Some people would look at this and say, "but what if the genetics have changed within the population over time?" Fortunately this doesn't apply to fish! Fish have "indeterminate growth", meaning that they can get as large as their environment allows. Usually this translates to available food sources, dictated by competition and food present.
Next time we'll look at some examples of Population Density and how that affects Fish Size as well as get into the limiting factors that play a role in method #3.
Till then, hopefully you can get out and enjoy the water. Personally I'm heading out tomorrow to do some ice fishing with my brother in law.