Reversal of direction of swimming by rainbow trout (Salmo gairdnerii Richardson) on stopping a current of water

摘要: Summary 1. One-year-old rainbow trout of an autumn spawning strain which had been kept swimming for several months against a circulr current water were observed to reverse the direction in they swam when was stopped. The majority would continue circuits aquarium new more than 5 hours. Yearling from January, did not their until end April, and development this behaviour coincided with loss parr marks assumption adult markings. 2. Brown upland stream circular 3. For weeks after reversing developed, sign response could be changed by submitting fish about two days flowing opposite direction, but at later stage taken stopped appeared become fixed. 4. Reversal occur if total darkness, nor unless able see surroundings approximately 2 3 hours period 1/2 hour darkness. Well established reversed through still abolished minutes