... the only correlation I can suggest is the smaller lakes where we provide fall-winter-spring put and take trout fishing, if we happen to be shocking bass off of nests this seems to be about the same time trout are no longer found.
And I don't know that this means anything but it's something that crossed my mind regarding the timing. I think your comment of free-for-all or none-at-all is both a possibility.
Small 2 ounce forage trout also grew fast, reaching a maximum of 1 to 1.5 lb in April. I think few survived that long, though.
These experiences suggest that the small trout may be vulnerable to LMB predation before DO is a problem for trout. Ken, if the trout were consumed by LMB prespawn, that might explain why they are not present during the LMB spawn. There is probably a temperature above which LMB have the upper hand. The number I threw out is in the neighborhood of the temperature spawning typically begins. At 60 degrees, however, the LMB may have no trouble taking small trout and this of course would impact success if stocked at this temp.
It would be great to understand the temperatures required to inhibit predation of small trout by LMB because to lower the cost, one needs to put some low cost weight on them. To have them consumed at stocking would just be a 1 to 1 forage addition. In the context of cost and benefit, a shorter growing season where the pre-spawn LMB feeding eliminates small trout, should be considered as well. Less feed would be used and less gain in weight achieved.
Most hatcheries sell forage for around $16/lb. So this is true of BG, RES, and even of trout. Whatever is gained between stocking and consumption by predators lowers this cost. If the pond could naturally double the weight of the 2 oz RBT, then the cost could approach $8/lb with no additional feed costs. Frank, you experienced an 8-tupling in weight for those that survived until April (which were few). Don't know your feed rates or how much went to the little ones but maybe a fair portion of the weight the little trout gained was from natural foods. A 25% increase in length is a doubling of weight. Maybe the thing to do is spend the feed budget on doubling the number of trout. Just take what the pond will grow them to and expect few to survive to April.
