Seasonal variations in the metabolism of mud crab, Scylla serrata during new moon and full moon phases of lunar cycle

Abstract

Lunar cycles affect the behaviour and moulting of crustacea. Correlation between lunar cycles and physiological activities is quite well known for teleost. However, in crustacea the metabolic changes that occurred during lunar cycles are not well studied. Hence, we undertook to study the effect of lunar cycles on the body metabolism of mud crab, Scylla serrata throughout the year covering all the seasons namely summer, pre monsoon, monsoon, post monsoon and winter. Increased rate of excretion in the form of ammonia, urea, free amino acids and trimethyl amino oxide and the increased rate of the aquatic respiration were recorded during full moon phase over the new moon phase of the lunar cycle throughout the year. The levels of tissue biochemical compositions like total protein, total carbohydrates, total fat, free amino acid, free sugars and free fatty acid remained significantly higher in full moon phase of the lunar cycle. Our results also show a significant seasonal variation in the body metabolism which is again focused on the breeding activity of the crab. The differences in physiological and biochemical parameters during new moon and full moon phases of the lunar cycle may be associated with the moulting behaviour or the feeding activity of the mud crab, Scylla serrata.