At the outset, and then once a month,without the use of anaesthetic
all fish were briefly blotted on a damp paper towel and weighed on an
analytical electronic balance to ±0.1 mg then immediately returned to
their tank. The growth measure at 1 month allowed us to examine
whether growth rates, or the optimum temperature for growth, varied
over the course of the experiment. Treatment temperaturewas checked
twice per day and all fish were fed to satiation with a 0.8 mm sinkingpellet
aquaculture diet for carnivorous fish (Gemma PG, Skretting;
nutrient composition: 56% protein, 18% oil, 10% ash), whichwas readily
consumed. Satiationwas determined byproviding sufficient food so that
a small amountwas left on the bottom of the tank after each feeding. All
tanks were syphoned clean every second or third day, as required.
were progressively brought to their treatment temperatures which
ranged from 19 to 29 °C. The remaining juvenile fish were left in the
holding system as possible replacements. The stocking density was
restricted by the limited number of juveniles available