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Hemolymph oxygen transport, acid‐base status, and hydromineral regulation during dehydration in three terrestrial crabs, Cardisoma , Birgus , and Coenobita

1981; Wiley; Volume: 218; Issue: 1 Linguagem: Inglês

10.1002/jez.1402180107

1097-010X

Warren W. Burggren, Brian R. McMahon,

Aquaculture Nutrition and Growth

Abstract Hemolymph oxygen transport, acid‐base status, and hydromineral regulation have been measured at 28–30°C in Cardisoma carnifex, Birgus latro , and Coenobita brevimanus in their normal hydrated state, following a period of severe dehydration, and after a subsequent 24‐hour period of rehydration. Cardisoma and Birgus tolerated a maximum loss of body water of 20%, which developed in 3–4 days without water, and resulted in an 25–30% increase in hemolymph osmolality. Ion concentrations also increased considerably, with the largest percentage increases in ion concentration occurring for Mg ++ , Ca ++ , and K + . A metabolic acidosis and a resultant fall in HCO developed in Cardisoma and Birgus , but PCO 2 showed no large changes, suggesting little respiratory compensation. Oxygenation of postbranchial hemolymph was not affected during dehydration, since P and hemolymph O 2 capacity increased, the latter because of a hemoconcentration. Within 24 hours of rehydration, a restoration of the original levels of hemolymph ions and osmolality occurred, and a nearly complete return to normal acid‐base status developed. Coenobita was distinctive, since dehydration to the maximum tolerated 28% loss of body water appeared to be accompanied by a closer regulation of hemolymph ion levels. Only protein increased, which probably accounted for some of the rise in hemolymph osmolality. However, hemolymph O 2 capacity fell, and that, in conjunction with a significant reduction in P , suggested a more severe disruption of O 2 transport than in either Cardisoma or Birgus . The metabolic acidosis and the fall in HCO during dehydration were also more profound, and Coenobita showed the least recovery of these three species after 24 hours of rehydration.