These experiences suggest that the small trout may be vulnerable to LMB predation before DO is a problem for trout. 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,
I am going to look into this to search for info.
is as follows based on my memory of several sources.
39 - 50 F - RT have the advantage of mobility and active metabolism . The colder it gets the less active the LMB will be.
51- 70 F - equal footing - bass metabolism starts to ramp up and then equal RT. LMB can and will feed on RT with the amount increasing on a sliding scale as temps rise. RT will have active metabolism up to 70 F +-
70 F + LMB have the advantage and as temps increase the advantage increases.
Best guess for success if stocking smaller RT - stock behind a blocking net (habituation) when temp gets to 50 F and feed them high protein feed. After a few days as temps drop you can remove the net and keep feeding. Would be good to have cover inside net area for RT protection after it is removed. Watch and adjust as needed.
The growth curves for largemouth bass derived from laboratory data (constant temperatures) indicated that growth is negligible below 10°C,
Is nearly linear in the range10-28°C, and declines abruptly above this
Value (Strawn1961;Coutant,unpublished report).
Largemouth bass consumed prey during winter at temperatures that were greater than or equal to 6°C. At less than 6°C, feeding continued infrequently. In our experiment, winter temperature drove much of the variation in consumption by largemouth bass in all winters. Metabolism of largemouth bass, like that of many fishes, declines with declining temperature (Brett and Groves 1979; Rice et al. 1983; Jobling 1993), likely contributing to reduced consumption. Although feeding continued through winter, it was infrequent below 6°C. Previous investigators have suggested that largemouth bass do not feed below 10°C (Markus 1932; Johnson and Charlton 1960).
Behavioral and Metabolic Adjustments to Low Temperatures in the Largemouth Bass (Micropterus salmoides)
Daniel E. Lemons
Larry I. Crawshaw
Food intake was measured during and after the acclimation period, and MR and activity were measured following the acclimation period. MR, measured in a closed system, was exponentially related to temperature with a Q10 of 3.0. Food intake declined linearly down to 10 C, below which it became negligible. Spontaneous swimming activity, measured in an annular tank, was similar for all fish at or above 7 C and was considerably reduced at 5 and 3 C. These data indicate that physiological systems respond very differently to low acclimation temperatures in the largemouth bass. MR shows no compensation. The central nervous system, which mediates activity cycles, shows perfect compensation from 17 to 7 C, with a decline at lower temperatures. An energy analysis reveals that food intake fails to meet even resting metabolic requirements at temperatures below 10 C and that the net cost of spontaneous swimming activity is a small portion of the total daily energy expenditure from 3 to 17 C.
Bioenergetics and growth of largemouth bass (Micropterus salmoides) in relation to body weight and temperature
Authors: A. J. Niimi and F. W. H. Beamish
For most weights, growth of fish (grams/day) was highest at 25C, and lowest in fish at 18C. This was attributable in part to a higher satiation (maximum) feeding level at 25C. For a fixed level of feeding, growth rate (percentage wet weight/day) was highest for fish held at 18C.Lipid content (percentage wet weight) increased with feeding level and was highest at 18C, Moisture content varied inversely with lipid. Protein and ash content did not vary appreciably with temperature, body weight, or feeding level.Maintenance requirement of bass, expressed as grams/day, was about twice that lost during food deprivation, but only slightly different when expressed as kilocalories/day.Energy requirements for nonfecal losses were estimated as 10% of intake energy at all feeding levels. Standard metabolism accounted for 50% of intake energy near maintenance, but only 10% at the satiation feeding level. Growth requirements increased From zero at maintenance to 40% of intake energy at satiation feeding
The minimum temperature for growth in trout is about 38o F. At this temperature and below, appetites are suppressed, digestive systems operate very slowly, and trout require only a maintenance diet (0.5 to 1.8 percent of body weight per day, depending upon fish size). Feeding more than this wastes feed. In warm water (above 68o F), a trout’s digestive system does not use nutrients well and more of the consumed feed is only partially being eliminated. This nutrient loading of the water, coupled with the generally lower oxygen levels in warm water, can easily lead to respiratory distress. In warm water, feeding rates should be reduced enough to maintain good water quality and avoid wasting feed. The optimum temperatures for growing trout are 55 F to 65o F. At this temperature range feeding rates should be at maximum levels (1.5 to 6.0+ percent of body weight per day).