STUDIES ON THE TUBE-BUILDING AMPHIPOD COROPHIUM TRIAENONYX STEBBING FROM VISAKHAPATNAM HARBOR: EFFECT OF SALINITY AND TEMPERATURE

¹ Department of Zoology, Andhra University, Waltair, S. India

1. Investigations were undertaken to determine the maximal and minimal salinity and temperature values at which the adults and juveniles of Corophium triaenonyx survive, to study the effect of gradual changes, and also to observe the temperature and salinity ranges of natural populations in the environment.

2. This amphipod tolerates wide ranges of salinity from 0.6 c to 59.8, which are the lower and upper lethal salinities respectively. Between 4 and 55 they live quite normally. Gradual increase or decrease in the salt content does not seem to have any effect on survival time. Animals in situ behaved in a similar way to those out of the tubes.

3. C. triaenonyx can tolerate temperature ranges from 5° C to 40° C. Survival times increase when the animals are subjected to move gradual changes. When the temperature is raised by 1° C every 24 hours they could survive up to 46° C. When the temperature is raised by 1° C every one hour they died at 44° C. Animals within their tubes seem to be more tolerant.

4. These amphipods tolerate lower salinities better at higher temperature, and lower temperatures better when the salinities are nearer normal values. Size and sex do not seem to have any influence on the survival time.