Pond Boss Forums STOCKING A NEW POND Creating the food chain Small LMB Gape and Proper forage size

I have read all those papers ... and yes ... smaller LMB tend to eat prey which is a larger proportion of their length. One hypothesis proposed by one author is that the risk of taking prey that they may choke on is outweighed by the need to grow fast. So small fingerlings take that risk more frequently. Rather than "it depends", I would say this. There isn't an optimum size that has to be fulfilled in order to optimize growth. There must be sufficient forage consumption to support optimum growth. In the reference you noted above, the author(s) talk about the maximum sizes depending on the body shape of the prey.

If a prey item has a similar shape, 1/2 the length results in consumption of ~10% to 12% the weight of of the predator. This greatly exceeds normal daily consumption for all but the smallest of LMB. It is much more normal for predators that swallow prey whole to consume prey less than 1% of their body weight. So consider a 2" LMB that one stocks in June that needs to consume 18% of its body weight daily for maximum growth. It would take two 1" FHM to meet its daily needs. Or it would take 12 1/2" FHM (about 1 per hour during daylight hours). So which is better? IMHO, it doesn't matter so long as the LMB is consuming what it needs for the day's maximum growth. Most of the energy burned will not be in the taking of individual prey. It will be burned between those encounters . In general, LMB consume a range of prey sizes that fit a log normal distribution. How a daily ration is filled by this size or that is less important than just consuming the ration by whatever means possible.

The latest papers I have read on the subject ... the authors tend to agree ... that energy outflow is proportional to time and that the time between predation attempts is not negligible nor is the energy consumed in a predation attempt a significant proportion of expended energy. Conversely, it is appropriate to look at consumption as a time rate of energy consumed. The key to consuming at maximum rates of energy consumption is abundant prey of suitable size. The range of suitable sizes is broader than many think. It takes more of smaller prey but the chance for successful encounters is higher and the number of encounters are increased if the smaller prey is abundant. This balances smaller energy per individual prey.

It would be wise to keep in mind that there is a significant difference between a 2" LMB and a 28" LMB and the prey they eat. 2" LMB can eat much longer prey as a proportion of their size than a 28" LMB can. The main reason for this is that prey morphology changes as the prey grow longer. A BG fry at the stage of swim up are skinny and spindly. They do not have as much advantage of laterally compressed defense against predation that they will gain as they grow longer. A 3" LMB can consume a 1" BG but a 28" LMB will not be able to consume a 9 1/4 inch BG. The 1" BG is like a fat minnow to a 3" LMB where 9" BG is just a too big too fat 9" BG to 28" LMB. One might find a dead 28" LMB with a 9" BG in its mouth. But this just demonstrates the risk can vastly outweigh the reward contrasted with smaller alternatives. Three 5" BG is all she needs during the warm months to grow larger. Now I say "all", but the sheer quantity of prey she needs between 4" and 6" in length each year makes clear that there cannot be many 28" LMB in a farm pond without supplementing forage. In waters that produce this size of LMB with natural production of prey, their density is quantified by acres per fish and not fish per acre.

Generally speaking, in a newly stocked pond, if you don't get good growth during the first year then something went terribly wrong. Prey for small predators should typically be abundant during this first year. Some other reason than optimum prey size would carry the blame for slow growth. More likely the cause is insufficient quantities of consumable sized prey. IMHO, just making sure there are abundant quantities of smaller than perfectly optimum prey will ensure maximum consumption and growth.