Pond Boss Forums MANAGING AN EXISTING POND Evaluating and adjusting fish populations Longevity of pellet fed fish

I've read that the faster fish grow, the shorter amount of time they live. I don't know if this is true or not.

When we feed fish, they grow much faster. Does this mean they don't live as long? This information is important for fish that we have to continually restock such as hybrid white/striped bass or hybrid bluegill. It says that we must restock a greater percentage of the total population each year. Any ideas on this?

Norm I have offten wondered my self if pelleted food was good for certain fish..even though they ate it I did not know if it was good for them as far as health sake and logevity...

The PondBoss (Bob Lusk) and I discussed this topic recently. Here is his opinion on this fish longevity thing.

Bob "thinks" each fish has some sort of "genetic program" that dictates how many heart beats or similar feature they have. Since fish are cold blooded, the warmer water they are in, the faster their heart rates. Southern fish live more days in warmer water than northern fish thus southern fish "use up" their "heartbeats" quicker than northern fish. This make sense to me, but this has not been scientifically proven yet.

Norm,, I'm not sure I completely understand your question. What or where does it say we need to restock a larger percentage of the total population of fish each year when dealing with "nonreproducing" populations? If there is no annual harvest or moratality why would we need to restock until losses occur?

Bill, obviously we have to continually restock non-reproducing species. Let's say we have 100 hybrid bluegills. If they live 3 years, we have to stock 33 per year. If they live 4 years, we have to stock 25 per year. If they live 5 years, we have to stock 20 per year. These are all averages, of course.

My question is does feeding these fish reduce their life expectancy? If it does, then we must add more each year.

Theoretically feeding fish properly formulated pelletized food should not shorten their life expectancy. BUT I don't think any long term studies have been done on the life spans of fish that are fed artifical food versus control fish that feeding only on natural food items. Some experienced fish raisers think many of the formulated foods contain higher amounts of protein and fats than the fish actually need esp for maintaing long life spans. Most feeds are formulated for rapid growth to market size (high production rates). Pellet fed fish may have a tendency to over-eat and become too fat; as with other animals, including humans. The rapid growth food stuffs and resulting accumulations of excessive fat may work to shorten fish life spans due to fatty livers, clogged arteries or other health concerns, similar to those of humans or dogs. For example, note the recent shift to various healthy formulations for various age groups of dogs. However too little work has been done on this topic and most fish raisers are only intersted in growing fish rapidly to large sizes. Very litle interest or demand is present for fish to have long life spans. Koi raisers are the exception and I think some special formulations have been developed for those fish.

I have seen some discussion among researchers that pellet fed largemouth bass may not make it through northern winters as well as other bass. However as far as I know I only lost two this winter with a few hundered pellet feed bass in the pond. There is some conjecture among researchers that not enough choline was available in the pellet diet.

There has been some research that says too much carbohydrates in pellet diets of carnivourous fish causes a diabetic or fatty liver condition. However one food researcher I know by the name of Paul Brown of Purdue University tells me fish can be functional diabetics -- that is -- they can handle the condition. Ironically with the new low carb diets for humans, the premise is that too many carbohydrates get stored as fats and is not good for the body.

I try to feed my feed low carb and high protein diets except for going into winter when I beef up the fat. I was introduced to this by a trout farmer that feeds "high energy" diets in very cold water and the reverse to his trout in warmer water.

Chiming in...Based strictly on experience, I can tell you this. I have seen too many undernourished fish not reach their potential. Those fish are more easily stressed,thus subject to greater incidence of environmental problems as disease and/or parasites. I am working with a landowner right now who has overcrowded largemouth bass with livers so choked with flukes their kidneys almost look non-existant. Try as we might, we haven't been able to "feed" these fish back to health. I'm afraid they have lived out their best years.
Yet, in another pond, with feed trained bass, those fish are vigorous, healthy and growing well.
My common sense tells me well fed fish survivability will be higher, and fish will live longer, if properly nourished. The key word here is "properly." Too much,or too little, may have the similar effect.
But, if I had to choose between well fed pellet raised fish, and overcrowded fish competing for limited food, I'll take the pellet raised fish.

A continual diet high in fat for at least some species of fish is suspected to cause fatty liver disease and shortens their life span. A varied diet is probably best in the long term.
http://davenmidtown.hubpages.com/hub/Fee...-For-Other-Fish

http://www.leaflakes.org/understanding-fish-nutrition-feeds-and-feeding/
An interesting item about fish pellets in the above article is:
""The pellet size should be approximately 20-30% of the size of the fish species mouth gape. Feeding too small a pellet results in inefficient feeding because more energy is used in finding and eating more pellets. Conversely, pellets that are too large will depress feeding and, in the extreme, cause choking. Select the largest sized feed the fish will actively eat.""

I feed every few days in warm months, sometimes go a week or more. My fish are extremely healthy and strong. Not overly fat though, and I have tons of forage fish for them. Just like humans, moderation is good. Sure, daily feeding leads to fat fish, but I am not sure daily is the way to go. I am new at this, so just speculation, but those who fish in my pond talk of the fishes strength and health.I think occasional pellets with good forage fish is the way to go, and I can't help but think the pellets give the forage fish an occasional rest from hungry predators.