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| Fish Math II by Todo Last month I did a little about how fish growth effects the biomass of your pond. Here is a related article I found on rec.pond The USDA Watergardening publicatiohttp://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/435fs.pdf offers this "consensus" fish stocking guideline: Unaerated pond: up to one 12" fish per 10 square feet of surface area. Aerated: up to one 12" fish per 2 to 3 square feet. and says conservative hobbyists stay well below these guidelines. To apply this to smaller fish, note that while their weight goes up almost with length cubed, their metabolic rate goes down with length. So feeding rate, oxygen demand, and stocking rate go with length squared, as a rough guide. So stocking four times as many fish, of half the length, is roughly equivalent. Until they grow! Pushing these guidelines requires good aeration and biofiltration, keeping the temperature from getting too high, not overfeeding, and increases the risk of losses during spring cycling. So there isn't a fixed stocking formula, but a range of difficulty. The rates the USDA gives elsewhere for professional aquaculture are much higher, acknowledging they can't be competitive without pushing the limits. That's in ponds designed with optimal aeration and filtration, not for appearance. It also demands full-time husbandry and accepts some losses. a |
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