Considering the large number of fishes native to Peru, it is recommended that no exotic species other than those already present should be introduced into Peruvian waters. One possible exception that might prove to be a useful addition would be coho salmon for pen rearing in coastal waters. However, rainbow trout which are already present in Peru probably would be satisfactory for this purpose.
Short-term survival tests using rainbow trout (25 an in length) in sea water pens adjacent to the Instituto del Mar in Callao resulted in survival of the 25 specimens for a period of 12 h after which they died as a result of oil being released in the nearby harbour. Water temperatures during the testing period varied between 17°C–19°C. Strong tidal currents caused some distress to the test fish for the first hour as the fish were becoming acclimated to the change from fresh to sea water.
During the period of the expert's observations of trout rearing facilities in Peru, there was little evidence of disease except at the Cajamarca station where unidentified causes resulted in losses of about 50 percent of trout fry.
