"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".
Eric, this interests me for a number of reasons but in essence it depends on % of lipids in the 180 RW LMB. So I wonder how much of the additional 80% is fat. Also how much water content is within the fat tissues? Lipids are super high in energy content and so a couple of things come to mind. First, does this in part explain why the intrinsic FCR worsens in cold water? By this I mean that if the LMB preferentially stores energy above its maintenance in the form of lipids instead of protein (which in muscle contains a lot of water) then weight gained will be less even though the gain of energy (of the LMB) is relatively the same. In that sense conversion on a energy basis could be better than the gain in weight would otherwise suggest. If that extra 80% were fat and if that fat contained only say 30% water then (.70 * 80/180) 31% of the LMB would be lipid and this would represent a huge store of energy that could take the fish through very lengthy periods without consuming.
Here is an example. Using average daily temperature as the water temperature, I compute that Dixon Lake LMB needs 4.93 lbs of BG per pound of LMB per annum for maintenance. Since BG are 4,186 J/Wet gram and lipids average ~37,000 J/Gram then we can calculate the weight of lipid required for energy per pound of LMB (4.93*4186/37000 = .55 lbs. If the LMB is 31% lipid then it has stored in its lipids enough energy to supply .31/.55 =56% of its annual energy requirement. Pretty amazing when you think about it. Dixon Lake LMB may need less than 4.93 lbs of BG if I am overestimating the temperature. IOWs they may inhabit cooler water than surface water which will vary around the average daily air temps each day. From this perspective I may have understated the reserve in terms of % of annual energy needed.
Imagine a 7.76 lb 23.3 standard weight LMB having turned the corner for consuming 1 lb trout could gain 80% in weight over the winter period by consuming 26 1 pound RBT. From November 15th to March 31st this would take one 1 lb RBT every 3.7 days.
