In BC triploids have been stocked for a while now and my experience, which is purely subjective, is that triploids will grow large, but they don't seem to fight as well as normal diploid fish. That could be due to environmental conditions rather than the physiology of the fish, but I have to say I haven't missed them too much while I've been catching wild Bow freight trains the last two years... Below are some quotes taken from various websites that tell a little more about triploids. As you can see from the last one, its important to play them quickly and leave them alone entirely if the water gets too warm...
How do fish farmers produce triploids?
To make fish triploid the newly fertilised eggs are physically shocked. In practice this means the eggs are placed in a special pressure vessel and subjected to a very high pressure. The timing after fertilisation and the actual pressure are critical to the process. If the farmer times this wrong then mistakes can be made. The balance is a fine one. Too little and it does not cause triploidy whilst too much pressure kills the eggs. It is difficult to judge the success until the fish can be sampled and examined under the microscope, or mature as adults. The triploid eggs go on to hatch and grow normally into adult fish. However it must be remembered that the process is a biological one and as such triploidisation is rarely 100% effective. Some fish of each batch seem to escape the process and mature as normal fish. We expect our suppliers to provide fry that are normally much better than 90% triploid. That is we generally expect that one fish in ten from a batch of triploids will develop eggs in maturity. It is therefore important that the farmer grades the fish to remove any hen fish before these fish are stocked into critical waters. This is a point often overlooked and a batch of triploids may still contain a small number of fertile fish.
The Physiology of Triploid Fish: A Model for Applied Research in Aquaculture.
Tillmann J. Benfey, Department of Biology, University of New Brunswick, Fredericton, New Brunswick, E3B 6E1
Triploid fish are sterile as a result of having three sets of chromosomes in their somatic cell nuclei rather than the normal (diploid) two sets. Although there are compelling reasons for using sterile fish in aquaculture, triploidy has not been embraced by the salmonid aquaculture industry because of real and perceived differences in their culture characteristics that can best be summarized as a reduced tolerance to chronic stress. Triploid salmonids also exhibit increased rates of jaw, gill and opercular deformities, as well as the presence of dividing and fragmented red blood cells. These effects of triploidy likely result from fundamental physiological differences between diploids and triploids that arise from increased nuclear and cellular volume in the latter.
Exercise Physiology
Triploids and diploids appear to have equivalent aerobic capacities (Stillwell and Benfey, 1997), but triploids have lower oxygen consumption rates when swimming aerobically in a respirometer (Stillwell and Benfey, 1996) and during recovery from exhaustive exercise (Hyndman et al., 2002a). The question arises as to whether the decrease in red blood cell surface area to volume ratio affects cellular oxygen consumption rates in triploids, but this does not appear to be the case: oxygen consumption rates of triploid blood are not significantly different from diploid rates (1.87 ± 0.51 vs. 1.67 ± 0.28 nmol/ml/min/g Hb, respectively; Currie and Benfey, unpubl.). The overall responses to exhaustive exercise at 9°C are similar in triploids and diploids, although triploids recover more quickly from acidosis, muscle ATP depletion and muscle lactate accumulation (Hyndman et al., 2002a). At 19°C, on the other hand, triploids exhibit high (90%) mortality within 4 hours of exhaustive exercise (compared to no mortality in diploids) and demonstrate reduced anaerobic capacity as reflected by an absence of phosphocreatine depletion and slower muscle ATP recovery and lactate elimination (Hyndman et al., 2002b). These results help explain the previously demonstrated reduced tolerance of triploid rainbow trout (O. mykiss) to elevated temperatures (Ojolick et al., 1995).