RESPIRATORY ADAPTATIONS OF THE ESTUARINE MUD SHRIMP,CALLIANASSA JAMAICENSE(SCHMITT, 1935) (CRUSTACEA, DECAPODA, THALASSINIDEA)

Open Access
Publisher Website
Google Scholar
Abstract
C. jamaicense survives exposure to aquatic and aerial anoxia for > 3 days. In normoxic water-saturated air it survives for .apprx. 16 days. The rate of O2 consumption (.ovrhdot.VO2) in air is < 40% of .ovrhdot.VO2 in water. Aquatic .ovrhdot.VO2 is regulated above critical O2 tensions (Pc) of 10-25 mmHg when animals are allowed to slowly deplete O2 from a sealed bottle. Mean aquatic .ovrhdot.VO2 of animals in a flow-through respirometer or in tubes placed in sealed BOD [biochemical O2 demand] bottles ranges from 50-68 .mu.l/g wet water per h over O2 tensions (PO2) above the Pc. After a 12 h exposure to anoxic water, .ovrhdot.VO2 is not regulated; post-anoxia .ovrhdot.VO2 in hypoxic water (37 mmHg) is initially less than .ovrhdot.VO2 measured in normoxic water (150 mmHg) before exposure to anoxia; post-anoxia .ovrhdot.VO2 in normoxic water is initially 2 times the pre-anoxia .ovrhdot.VO2 and suggests development of an O2 debt during anoxia. When PO2 of ambient water is abruptly dropped from 150 to 37 mmHg, specimens of C. jamaicense exhibit a partial shutdown of aerobic metabolism, but the .ovrhdot.VO2 begins to recover after 6 h in hypoxia. When O2 tension is slowly decreased, pleopod ventilation rate varies little as PO2 changes from 120 to 20 mmHg. Pleopod ventilation rate increases as PO2 falls from 20 to 10 mmHg, but decreases below 10 mmHg and stops after several hours under anoxia. The rapid response of taxis and pleopod activity when C. jamaicense is exposed to altered PO2 suggests rapid perception of external O2 levels and provides further circumstantial evidence of an O2 receptor in thalassinids. Tolerance of anoxia, metabolic regulation to a low Pc, low metabolic rates, metabolic responses following anoxia, and taxic response to altered PO2 constitute adaptations to the hypoxic habitat of C. jamaicense.

This publication has 2 references indexed in Scilit: