AGE AND LIPOFUSCIN COMPOSITION RELATIONSHIP OF BLUE SWIMMING CRAB Portunus pelagisus IN CAPTIVITY.  

The blue swimming crab, Portunus pelagicus, was one of the main species of crab at Setiu WetlandS and have been caught by fishermen for decades due to their high commercial value. Until now the status of the P.pelagicus in the Setiu wetlands have not been studied by any researcher. This study was carried out to estimate the age of the P. pelagicus using lipofuscin extraction for better understanding with their population. The samples were cultured in a hatchery and every month the eyestalks from available juvenile crabs were taken and LF extracted. The procedure was repeated until 1 year of data completed. As for the correlation analysis between males and females, there are no significant different at p =0.05. There are both positive linear relation of LI and age for males and females of blue swimming crab. The linear regression of males P. pelagicus was LI = 3.3634(t) - 1.1509 with R² = 0.768 and LI = 3.8246(t) - 3.7268 with R² = 0.8478 for females. Overall, the regression line for total samples combined was LI = 3.5908(t) - 2.4058 with R²=0.8071, respectively. The LI of both male and female eyestalks were not significant at each other. This has showed that the metabolic rate in crab's cells is at equal rate for the different sexes. Since the traditional length based methods of age determination have proven inaccurate, population analysis using LF as an index of age should be used to develop more robust population dynamics models. This would help the fishery sectors to accurately understood the population biology and contribute to the knowledge regarding age and growth in crustaceans.

Key words: Lipofuscin, age-lipofuscin relationship, age estimation, blue swimming crab, P. pelagicus.