Growing Trophy Bass in Private Lakes in Tennessee: the Importance of Genetics

‍ ‍Your lake is your oasis; you owe it to yourself to hire the right biologist to manage it. The biologist you hire can make the difference between your lake being that dream fishery you always dreamed of, or a constant source of disappointment and frustration. Whether your lake is in Franklin or Knoxville, Chattanooga or Memphis, or any corner of this state, you have several lake management companies vying for your hard-earned dollars; they will all tell you they’re the best choice to give you your dream lake. At first glance it may seem difficult to choose; it may even seem that there’s not that much difference between us. Nothing could be further from the truth. The biologist you choose determines the success or failure of your lake’s fishery.

But how do you choose if every company has degreed fisheries biologists? If they all claim to be the best, how can you, the landowner, separate truth from marketing and get the right guy? We recently published another blog post that lists some basic things to look at, such as what your priority for your lake is, what the lake management company’s corporate structure is, etc. When choosing a fisheries biologist, nothing is more important than the biologist’s knowledge of fish; a biologist who has read widely in the field of fisheries research and has many years of experience is going to do a better job managing your lake than someone who doesn’t read the science and has only worked in the field for a couple years. One area of lake management that is talked about a lot but poorly understood by many biologists is genetics.

There is no other single facet of fisheries management as important to the ultimate success or failure of your lake as genetics. Many fisheries biologists in this country today will tell you otherwise; and when they do this, they are giving you a gift, the gift of knowing they are not the ones you should hire.

The field of genetics was founded by the nineteenth-century Austrian biologist Gregor Mendel. Mendel did experiments with pea plants. These experiments led him to formulate the laws of Mendelian inheritance, which in turn became the foundation of the science of genetics. One of the laws of Mendelian inheritance is the law of independent assortment, which states that genes controlling different traits are inherited independently of one another. This is how a short man and a short woman can give birth to a child that is tall, or how a healthy man and a healthy woman can give birth to a diseased child. Environment also plays a crucial role in gene expression: for example, studies have demonstrated that the offspring of wild fish brought into a hatchery for broodstock, within a few generations, will evince markedly increased feed-conversion ratios compared to the original broodstock. So fish’s genes will morph from generation to generation based on their environment.

One of the largest lake management companies has an article on their website about a large private lake that they worked on. The article notes that the lake was initially set up for success, stocked with ample forage, followed by largemouth bass with the best genetics. The article states that the lake produced good fishing for a few years, and then began to decline as the owner stopped managing it.

This particular article has as its thesis the idea that genetics are secondary in importance to other factors such as forage, water quality, etc. To be sure, these other factors are important. But the author of the article, who happens to be the chief fisheries biologist for this very large company that at present has many times the customer base and revenue that we do, goes so far as to say that the genetics in that failing lake now, more than ten years after it was stocked, are the same genetics that were in the lake when the bass were first stocked.

Bass spawn. Just as the children of human parents rarely ever look exactly like their parents, or have all of the same traits, so do fish rarely ever look exactly like their parents, or have all of the same traits. And in ten years’ time the genetics of a fish population can change so dramatically as to be unrecognizable from the original fish. Even beyond the principles we alluded to earlier of independent assortment and of adaptation to environmental factors, there is another extremely basic, extremely crucial force at work when fish spawn in a closed system: it’s called inbreeding. It’s the first thing one learns about in the first ten minutes of learning how to start and run a fish hatchery; if you ever take a course in aquaculture, the first thing they teach you about breeding fish is that you have to take specific, regular steps to minimize the chances of inbreeding occurring. In a private lake that has had no new bass stocked in ten years or more, inbreeding is not a possibility, it’s a certainty.

You don’t want a biologist who thinks genetics don’t change in ten years in a closed system. Entrusting that biologist with your lake is akin to hiring a doctor who believes in leeches to do your heart surgery.

Among lake management companies, there are big companies, and there are small ones; there are corporately-owned companies, and privately-owned ones. It can be difficult to separate the experts from the pretenders if you only look at the number of employees, or how many states they have offices in. But if you spend a little time delving into what they say about fisheries science, you can glean their level of knowledge about managing private lakes, and make a better decision on who to hire to create your dream fishery.