What happens to a lake as it ages to cause a decline in the heavy weight fish?

Like some of the western lakes, what happens if it dries up and eventually refills....is this essentially a reset button or will it never return to its as new state?

Does a decline happen to every lake or can management save it?

Just asking because age comes up often in regard to Fork but the LMB virus had an effect as well. Without the girus, would age still have caused a decline?

Since I became the Texas B.A.S.S. Nation Assistant State Conservation Director in 2007, I've attended several "Conservation Summits" (at the Classic, and elsewhere). From what I've learned, here's my take...

Lakes are graded, and aged under a "Trophic" identification format. Soon after a reservoir has been impounded, its nutrient levels are low, and productivity (or lack of fish production) is reflected. This stage is known as "Oligotrophic". As the reservoir ages, its nutrient levels increase, which assists in the establishment of a healthy food chain, and again, a healthier fish production. This stage is identified as "Mesotrophic". If a body of water becomes saturated in nutrient and plant growth, then it is determined to be in a "Eutrophic" state, and all productivity comes to a near screeching halt. Most older reservoirs sit between a Mesotrophic and Eutrophic state...and proper management can keep a reservoir healthy, or bring it back to acceptable productivity. Management tools such as introducing native aquatic plants to keep excess nutrients in check, and annual stockings of bass will help a lake to maintain its productivity.

For the most part, Highland lakes take longer to evolve to into Mesotrophic and Eutrophic stages than do Lowland reservoirs. Yet other factors such as poorly maintained septic systems around a given lake, and nutrient-rich feeder creeks/rivers can also accelerate staging.

If a lake completely dries up (and then refills), it will re-start (for the most part), but the nutrients that were deposited into the sediment on the lake bed will kick-start the "new" water into a higher 1st level.

As for your question regarding if every lake goes through this, I've been told that the answer is "Yes". That being said, I highly doubt that the TPWD will allow Fork (or any other Texas lake for that matter) to reach a stage of unproductivity. But the nutrient pendulum will swing back and forth, and productivity will ebb and flow.

Fishing pressure will also negatively affect fish productivity, but it can be kept in check with good management policies. Fork has held up very well over the years, considering the pressure that it receives. If it declines, it will come back. Falcon and Amistad are other examples of the ebb/flow in productivity.

Hope this helps to answer some of your questions.

Wow....now that is the answer I was looking for!!!

Thank you.

Now if we could just increase stocking of lakes other than Fork , like Ray Roberts , then all the lakes would stay good

Ron,

Every time I see an answer like Ron's, I can assure myself a little more that this country actually did put a man on the moon. Good stuff there Ron.

Lakes typically have a life cycle when it comes to the management of "heavy weight" fish as you call them. If the lakes are planned properly they are stocked with forage and a fertilized initially (if they need to be) to allow the food chain to flourish. When the initial stocking of LMB hits the water, the lake is primed and ready for their growth and this initial class of fish has an advantage that will never be seen again in the life cycle of the lake. As the cover begins to degrade in the lake over the coming years (dead plants and organisms convert over to sulfur compounds, silt begins to change bottom contours, etc) the lake becomes less and less ideal for the forage and ideal water quality that will grow the heavy weights you mention. Couple that with the fact that here locally you lose your controls on the specific genetics you stocked with (Florida strain) and interbreeding occurs which will decrease your potential weights over time.

You can see the owners of private lakes drain a great lake only to start over again and get the handle on these variables once again. Of course there are exceptions to every rule..... Mother nature is a crazy lady and don't forget about things like trout stockings or other human influences that change the direction of a lake.

Hopefully Salex (Steve Alexander) will be along and give you some other great information to couple with what Ron has put above to give you a better idea of why lakes produced large fish the way they do.

I think the bottom line for a lot of us is that Lake Fork will never be the lake it once was, but with proper management techniques it will keep fishing really well for generations to come.

Jackson

Ron gave a great explanation of the evolution. A few generalities that we often see in smaller private lakes. Lakes peak in years 8 to 12. The food chain is usually out of whack without harvest in year 4 and beyond. Genetics get diluted as outside watersheds (ponds and creeks) introduce unwanted genetics or rough fish. Habitat (brush piles and trees) have degraded. After year 12 most lakes begin to decline and seldom experience those golden years. In small lakes, like the ones we manage, there is a growing faction of lake managers that encourage draining these lakes after about 15 to 20 years and starting over. In many cases it is less expensive to start over than to try and rebuild the habitat and food chain. You mentioned hitting the reset button. It is a lot easier to hit the reset button on smaller bodies of water. Not practical on a large public lake. So, enjoy the golden years when a new reservior opens. It likely will never be as good as it was in years 8 to 12. Exceptions can and do happen. One of the biggest ways is that when lakes get down so low; stay low for years and fill back up a few years later. We may see this at OH Ivie or Medina in years to come. The drought may be really good for a few lakes, but hard to see the 1/2 glass full perspective for many.

Let Hubbard creek fill up and the fishing would be outstanding once again. It is covered with 4-6' salt cedars. Would be like a lake with lots of hydrilla giving the fry a place to hide and cover for bait fish.

Love the answers.

Many people here just repeat what they read or hear with no true understanding of how lakes age or progress through stages.

Falcon was one of the best recent examples of how a very old reservoir can go from years of being good to other worldly great after being filled after years of low water levels. What it's not an example of is how long this rejunination can last with constant water levels.