Pond Boss Forums GENERAL QUESTIONS Help bass weight gain

Bob Lusk says it takes 10lbs of forage to gain 1lb of bass. How much forage does it take for bass to keep from losing weight? Is this 10lb rule apply to all sizes of bass? For example, if a bass is 2 lbs does it take 10 more lbs to get to 3lbs and if a bass is 11lbs does it take 10 more lbs to get to 12lbs?

This is a very good question that I think 'ewest' should investigate for one of his Science and the Cutting Edge Pond Boss magazine articles. 'ewest' is IMO our fish bioenergetics guru. Energetics - the branch of science dealing with the properties of energy and the way in which it is redistributed in physical, chemical, or biological processes.

Read through this post from the Archives about Bass Management for some info on this topic.
http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=130299#Post130299

This is my 2 cents on this. The 10 lbs rule for bass or predator weight gain is based on the basic ecology food chain trophic pyramid where each higher trophic feeding level loses energy/biomass by a general factor of ten. Note all fish that eat other animals are a predator (aka heterotroph); even panfish that eat insects are technically predators. This is in contrast to autotrophs who manufacture their own food i.e. plants.

There is likely some variability in this 10:1 eating weight gain ratio based on numerous ecological factors. I think one of the main factors is how much energy the heterotroph (predator) needs to expend in capturing those 10 lbs of food. Having to expend excess energy capturing food would IMO increase the 10 lb:1 lb ratio for the target 1 lb weigh gain. Keep in mind that most of the biomass (weight) a predator eats is comprised of mostly water, sometimes 90% or more.

IMO the 10 lb rule is an average for all sizes of heterotroph - consumer. It stands to reason that one would need more consumables when growth is the fastest. Plus it has been shown that as fish get older the amount of food (percent of body weight) consumed per day/year decreases. This is likely due to slower overall body weight increase.

I think that ewest has covered this topic previously, but I could not locate it. He will hopefully respond. When he does, I will but this thread in the Archives for LMB Culling and Management.

So to answer your initial question of biomass needed for a bass to maintain a constant weight my best guess is about 5 lbs per year.

I don't know but Bob recently said that the 10/1 ratio is for all fish. Not sure I understand the whole thing regarding sunfish, etc.

It seems to me that a 10 pound bass would take more forage to maintain and grow than a smaller fish.

I struggle with the 10 to 1 forage to weight gain ratio numbers as and absolute number also. An example..If I stock a 1 ounce LMB in a pond full of FHM he will need to eat 10 ounces of FHM to reach 2 ounces in size. That is conservatively 200 FHM in the 1 to 1.5 inch size. If we give our little LMB the benefit of the doubt and assume he can digest a FHM per day, it will take him 6 months+ to grow from 1 ounce to 2 ounces. I suspect that little LMB will be much bigger than 2 ounces after 6 months. Would it be more correct to say the 10 to 1 ratio might best be provided as the average consumption/growth during the "teenage to adult" lifetime of the fish? Or maybe, over its life a 10 pound LMB consumed 100 pounds of forage? I suspect that growth vs consumption, if plotted on a graph, would be a very steep curve in the early life of a fish that flattens out as the fish gets older/larger.

Just my 1 cent