Variações de temperatura e salinidade do meio e seus efeitos no processo de osmorregulação da lagosta Panulirus argus (Latreille, 1804)

Abstract

The lobster Panulirus Argus, for decades, is the most important fishing resource in the Northeast. However, due to the sharp fishing effort, the stocks are currently over-exploited.One solution would be the development of technological packages which make easy the growth of this species in captivity. The place where the lobsters live appears to be the definition of comfort based on the environmental context, when we analyze the environmental characteristics due to the comfort zone of cultivated species. The objective of this work was to evaluate the mixed effect of differents temperature and salinity in controlled laboratory environments by determining and interpreting the osmolality of the hemolymph of Panulirus argus lobster. The study was developed at the Center for Studies in Aquaculture Coast Sea Institute of Sciences of the Federal University in Ceará between April 2014 to January 2015. Lobsters were evaluated (both sexes) when they were abruptly submited to varying conditions of temperature and salinity for a continuous period about three hours. The experiment was achieved in two steps, based on each of the set temperatures, respectively 22°C and 28°C.Combined effects of temperature with different salinities (15‰, 20‰, 25‰, 30‰, 35‰,40‰) were checked with a total of four repetitions for each tested salinity. The temperature were monitored, dissolved oxygen, pH, salinity and animal behavior as mobility and acceptance of food. It was observed there were significant differences (p <0.05) in Osmoregulatory behavior of Argus Panulirus lobsters that live in environments in terms of different salinities and the animals submited seawater around osmolality 1127 mOsm (40 %) to 22 ° C and 1081 mOsm (40 %) to 28 ° C were possibly in comfort situation. Despite the significant absence (p> 0.05) of the variation of osmolality of the hemolymph following the two temperatures tested in selected animals to the same salinity, it is clear that individuals kept at a temperature of 22 ° C results showed 100% survival when exposed to salinity of 20 ‰ considered lethal for lobsters. When these animals are submited bruptly to salinity of 15 % in these two temperatures tested showed 100 % mortality in the first three hours of exposure.The physical and chemical parameters , oxygen and pH of the water remained normal standards regarding lobster Panulirus Argus maintained in the laboratory.