I know I have lately been harping on "Quality Regs" and "Catch and Release", but for fisheries to be productive, it all lies in the hands of the fishery biologist and most of all mother nature. Sucess in growing big bass can be very complicated. The largest bass in the country are being genetically manipulated in Georgia, Texas and California which have long, warm growing seasons. For the rest of us, we depend upon "Quality Regs", "Catch and Release" and "Natural Selection."
For regulations to be sucessful, three things must be understood: growth rate, recruitment and mortality. Growth rate is how long it takes a fish to reach a certain size. Two pounds per year is exceptional growth. Three pounds in three years is considered to be rapid growth, and three pounds in five years is slow growth. Two major factors influencing growth rate are length of growing season and the availability of food.
Recruitment is the number of young fish reaching adulthood per year. A lake needs to have its shoreline supported with 20 to 40% aquatic plant coverage to have a high recruitment rate. If it has 0 to 20% coverage, it has an average recruitment rate. If a lake has a high recruitment rate, the growth rate will be good and the mortality rate will be low. Low water levels will result in low recruitmnet rates because it pulls the shoreline away from shoreline vegetation. High high water levels will improve recruitment rates by pushing water levels into shoreline vegetation.
Mortality is the rate from harvesting and natural causes. Overharvesting can deplete lake stock and mother nature has many ways to influence mortality such as water quality, temperature, changes in water chemistry, infections, infestations, etc.
It is the interaction between growth rate, recruitment and mortality that has the greatest influence on regulations. One may think the best growth rate, recruitment and mortality rates would produce the biggest bass. For a new lake this may be true, but for an older lake, one or more of these factors may need to be adjusted to keep the fishery regulated. Harvest numbers and fish size may need regulation. Selective harvest can help decrease numbers of small fish so to improve growth rates. Even food sources may be manipulated to improve growth rates.
Slot limits work best in highly fertile and productive lakes. Slots protect quality fish with the potential to become trophy fish. The slot allows the harvest of smaller fish, thus preventing over population. The problem with slots lies in fisheries with "slow to moderate growth rates" and with "harvesting." Most bass in lakes with slow to moderate growth rates simply do not have the ability to grow larger and there needs to be less competion for food. It is important that the fish below the slot be harvested. Catch and Release along with slot limits may result in increased numbers of small fish and decreased growth rates if these small fish are not harvested. For some this is hard to understand, but adequate harvest must be achieved. Every lake is different, and regs will be different from lake to lake. From biological surveys, chemical analysis and water quality testing, the fishery biologist try to make the right adjustments to regulate fish populations...not an easy thing to do. And, in the grand scheme of things, Mother Nature usually has the last word anyway.
In the future, don't be surprised if the regs on Dale will need adjusting. Remember, lakes reach their peak production between 5 and 12 years. Once a lake reaches 15 years old, growth rates begin to fall because decreased cover leads to decreased recruitment. Old lakes need vegetation and cover and efforts should be made to stimulate shoreline coverage. This may be accomplished by supporting deep water vegetation growth or by lowing the water level for a period of time to allow vegetation to return. This why Cumberland will be more productive once the water level returns to normal level after the dam work. Look what they are doing at Cedar by lowering the water level to force the smaller fish out from cover so the bass can feed. However once the water level is pushed back into the new growth vegetation, recruitment will increase once again.
What makes Dale grow large smallmouth is the fact that it is a clear water lake which supports photosynthesis down to 40 or 50 feet. It does not need shoreline vegetation to have high recruitment rates. Dale's weedbeds are the focal point for a healthy foodchain. Dale,s rocky shores also provide the favorite food for the smallmouth which are crawfish. If you add in the shad and trout in the mix, you have something special for an old lake that seems to have the stuff to sustain itself. We are lucky to have such a lake here on our doorstep. For now, I will step back, take a breath and maybe go fishing this weekend. Good fishing to all.
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