Pond Boss Forums INTRO Questions & Observations fodd to weight gain ratio

I just saw it here and now cant find it even with the search.
How many pounds of food does it take for a fish to gain a pound? Is this pellets? What about pounds of baby blue gill and minnows for LMB?
Thanks!
jim

For high quality fish feed, the ratio is 2:1. Two lbs of feed puts on a pound of weight on the fish.

For fish eating other fish, the ratio is 10:1. Fish needs to eat 10 lbs of fish to gain one pound of weight.

Wow 10 pounds of small gills and minnows would have to be a lot of individuals!
Thanks for info. Makes feeding seem more practical.
jim

Feeding has been shown in studies to be from 4 to 8 times more efficient than chasing natural food. It is not perfect but is a beneficial choice.

Jim, the difference is mostly that food pellets are dry, while fish are predominantly water.

Could you please expand on that statement providing examples of what you mean by that and findings you are referring to?

If we are talking LMB eating fish as natural food we need to take into account the dry weight and when we do the difference isn't all that great. The moisture content of whole fish is about 75% of the wet weight and if an LMB gains 1 lb on 10 lbs of fish then the conversion is 2.5 lbs dry matter to 1 lb gain LMB. To be sure, LMB don't have to work for feed but I don't see the 4 to 8 times more efficient than natural food from expending less energy.

Jim,

The easiest 1 pound to gain is the first pound. Most studies deal with young fish and relatively small fish. A five pound bass will not gain 1 lb on 2 lbs of feed (assuming here that is all it has to eat). The reason is that there is such a thing called maintenance. The 5 pound bass probably needs in the neighborhood of 7 lbs of feed annually to gain 1 lb (again assuming that is all it has to eat).

The bigger a fish gets, the worse the FCR is. For catfish, when they weigh about 1 lb the instantaneous FCR is about 2 lbs feed to 1 lb gain. What this means is that if you had pond full of 1 lb catfish and feed them 30 lbs today ... you would have 15 lbs more catfish tomorrow in the aggregate. To get the best FCR, you have to feed them fast. That is, maintenance must be small so that the feed is mostly converted to gain.

At rates most people supplemental feed, say 1 lb/acre-day, one is NOT feeding fast and the feed does not convert at 2 to 1 UNLESS the fish are fairly young and there is a lot of natural forage providing what they need for maintenance.

JPS, one reason I don't feed more heavily, aside from cost & bother tramping around the pond, is that too much ends up in a goose or duck. Wish a higher percentage of pellets sunk.

You know, that is a great point. Critters like birds can cause a loss of conversion also. Sinking pellets probably would help particular when feed rates are modest as you currently practice.

There are some pretty cheap things that folks can do that makes food naturally. Adding organisms that consume and recycle foods that are not sufficiently exploited(like tilapia and crayfish do with FA and detritus). Adding substrate (like brush) to increase attachment surface. Another thing that makes food is the right trophic balance where fish are not so numerous as to significantly inhibit production of their prey organisms.

From Fish Nutrition- Applied Science for Small Waters

Bio-Energetics - The study of the flow and transformation of energy within a particular system. Bioenergetics is the subject of a field of biochemistry that concerns energy flow and transformation through living systems.


Because fish growth often is limited by food availability, supplemental feeding is a logical tool to improve the condition of fish in small impoundments as the energy cost for bluegill to feed on pellets is small relative to the high caloric intake, which can be 4-5 times greater than those fed natural foods (Schalles and Wissing 1976).


These results indicate that total fish production and production of bluegill were each increased approximately 75 to 80% by supplemental feeding in 19 months after stocking (Schmittou 1967)

Most measurements are in energy (calories).