You have to account for energy used to catch food. In the CA lakes the RT are like pelleted fish food - easy to catch without much energy used.
Eric, you may be underestimating the metabolic requirements between consuming prey. They are there too and unless it is very, very, difficult to capture prey the energy savings of easy consumption may be less than we tend to give it credit. When I apply energetics and the dry weights of wet forage ... I am seeing that wet fish conversion is on par with feed for equivalent digestible energy consumed. One of the key differences, however, is that it is possible to consume more digestible energy with feed because it is fed in a dry state. Consumers have to negotiate the water content of wet fish and this diminishes how much energy they can consume of wet fish relative to feed. Improvements of conversion, apparently, come only from the increased consumption of energy ... particularly that portion that exceeds energy required of metabolism. Although metabolic demands for energy increase with increasing consumption ... this is apparently only partially related to the predation expenditure of energy. Just the digestion and assimilation of nutrients require energy as it is not 100% efficient.
I whole heartedly agree that supplementing forage is like feeding a pelleted feed. In the case of typical LMB ponds, unless one is feeding formulated feed directly to the LMB it is much better than feeding the BG to feed the LMB. Fish comprise a very minor part of pond nutrients being several layers removed from primary production. If one can afford to produce forage outside the fishing pond in a forage pond then adding the forage is approximately the same as adding their dry weight of a 67% protein feed comprised solely of fish meal. To grow the same weight of forage using the natural chain of the fishing lake requires a commitment to nutrient mobilization far in excess of that comprised in the forage supplement. In a forage pond, one can grow forage in hyper-eutrophic condition at high density and then put of fraction of the nutrients required to grow them into the fishing pond. Forage introductions make possible predator standing weights much greater than the trophic status of the fishing lake would otherwise support. Dixon Lake is a very good example of that strategy where the clarity most of the time exceeds 3 meters (9.8ft+ = low natural productivity close to oligotrophic). Cody note- how many ponds or small lakes with have this clarity and the sizes of trophy fish as Dixon??
