The Effects of High Temperatures on Roach ( Rutilus Rutilus )

Abstract

When roach were acclimatized to 20° C. and then subjected to five constant rates of temperature rise, the range of death temperatures depended on the interaction between the opportunity for acclimatization and the exposure to lethal temperatures. At 1/20° C. an hour rise in temperature, roach acclimatized fully, died over the longest temperature range (30-3-35-8° C.) had the highest mean death temperature (32-9° C.) and died over a disproportionate length of time (up to 88 hr.) when compared with other rates. The death temperature range at 1/10° C. an hour was 30-8-32-0° C. (mean 31-4° C.) and at 8/10° C. an hour was 31-5 to 32-9° C. (mean 32-9° C.). Roach cannot acclimatize fully at rates faster than 1/20° C. an hour though some acclimatization takes place at a rate of 8/10° C. an hour. Roach excrete more ammonia as the temperature rises but the increase depends on the rate of temperature rise and is delayed for up to 240 hr. at 1 /20° C. an hour. The behaviour showed characteristic changes. Roach died from the posterior end forwards ; the heart was beating and the gall bladder abnormal when the body was opened.