Originally Posted by ewest
This in regards to California largemouth that reach twenty pounds:

"The balloon-like proportions of these fish indicate adaptive specialization at its extreme limits. Just as coyotes have adjusted to susbist on garbage and poodles in the Los Angeles suburbs, California bass have adjusted to feed on stocker rainbows. Staying close to this food source, which has a preferred temperature around 54 degrees F., keeps these bass in the cooler fringes of their environment, which in turn triggers the fat-storing mechanisms of a pre-winter metabolism. As a result, an 18-pound California largemouth is no longer than a 10-pound Tennessee bass, just a heck of a lot fatter". Tracked down several of the state guys who did the transport and stocking. They described the stocking as mostly 1-2 lb. fish, which were upon release immediately ambushed by LMB. With no habitation they guessed that predation was 25% in the first few hours after release.

Would be nice if Texas would stock 1 to 2 pound RBT! Here in Texas it is generally 8" to 10". The LMB in Dixon must be the reason they are stocking trout so large. To help with survival. I've no doubt they guessed 25% but it still seems like a large number to me if for no other reason because of the number of LMB that would be required and the average size required. Not being exposed to predation they are thrown into a situation where the LMB know what to do and they don't ... so they are definitely more vulnerable in the first few hours. Even so I doubt the RBT just give up without trying to get a way and I would bet the 180 RW lunkers are no faster than 14" to 18" RBT ... so I would bet that the LMB focus on the smaller 14" trout of the stocking. If the CFDW were challenged to demonstrate that trout stocked weren't being wasted with 25% gone in a few hours and presumably the lion's share of the rest in a few days ... I would bet that they could justify that losses were muted and that most RBT are being recovered by fishermen. One of the ways they could do this is to explain that they go to a lot of extra expense to grow the trout big and they could demonstrate with science that bass are only taking a small percentage of the stockings because only a minority of the bass in Dixon are large enough to consume them.

Consider the table below. Generally 50% the length of the LMB is considered a practical limit for consumption of fusiform prey. Its not that they cannot swallow modestly longer prey ... but to be successful at capturing prey the length of fusiform prey is usually under 50% the LMB's length. When 50% prey is consumed they may be dead already, in the process of dying, or just incredibly unlucky. It happens but it is not very frequent. Given that the trout are not habituated, let's a assume the LMB are consuming live and vigorous RBT up to 60% of the LMB's length. For the minimum sized 1 lb stocker (14"), this requires a minimum length LMB of 23.3" and at 180 RW we are talking 14 lbs. This is the minimum sized LMB needed to consume the smallest of the trout stocked. A four thousand pound stocking averaging 1.5 lbs fish will have in the neighborhood of 2666 RBT and if 1/4 are 1 lbers, then the standing weight of >14 lb LMB would have to exceed 137 lbs per acre ... that is ... if none of them were heavier than 14 lbs.

So maybe they eat more than one RBT for each LMB in the first few hours. To test that theory I computed % of body weight of the consumption. It just doesn't make sense that a 23.3 " LMB would consume 13.4% of its body weight twice in one day. If it managed to consume one, I truly think it would stop eating for a while. Even adjusting for 180 RW 7.44% seems much too high to consume a second RBT which would likely have to be larger than the first. Now I am not saying that 25% are not consumed but if those guys are correct then it requires a huge standing weight of >14 lb LMB. If it takes a 23.3" LMB to consume a 14" RBT then one must ask the question. How do LMB in Dixon get to 23.3" in first place? It can't be the trout ... they must be eating other things. So the natural food chain would have to grow them to 23". I doubt that in this lake that enough 23.3" LMB are produced by the natural food chain to balance the trout consumption they figured. Also keep in mind that trout die of stress naturally over a two week period after stocking. These and those taken on the day of stocking should be sufficient grow > 14 lb LMB of a more modest standing weight quite remarkably.

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