Physiological tolerance in the polychaetous annelids Capitella capitata and Paraprionospio pinnata

Physiological tolerances were studied experimentally in the polychaetous annelids, Capitalla capitata, Parcprionospio pinnata and some organic pollution indicator species. 1) Salinity tolerance: Diopatra bilobata was the most tolerant among four species, C. capirata, Paraprionospio pinnata, Nebalia bipes and D, bilobata. 2) Thermal tolerance: D, bilobata was the most tolerant among above four species, and in the other three species, N. bipes, C. capitata, P. pinnata were in order from high to low in tolerance. 3) COD tolerance: The range of COD concentration in chich survivorship of the worms examined exceeded 50% for C. capitata was 27.5 to 57.0 ppm and as for D, bilobata was from 12.0 to 22.0 ppm. 4) Tolerance to the combination with temperature and salinity, temperature and COD concentration: The more salinity decreased, temperature increased and COD concentration decreased, the more survivorship of C. capitata decreased. 5) Tolerance to low oxygen tension: Lowest point of dissolved oxygen concentration of independent zone of oxygen consumption was 2.1 ml/l in C. capitata and 2.4 ml/l in D. bixobata. C, capitata was more tolerant than D, bilobata in. low oxygen tension.