Lipofuscin Level in Eyestalk Blue Swimming Crab, Portunus pelagicus at Different Sexes

BACKGROUND AND OBJECTIVE: The accumulation of lipofuscin (LF) is an alternative technique to identify age of crustacean species. However, the exact sites and the level of the LF concentration were unknown especially for different sexes of blue swimming crab, Portunus pelagicus. Thus, the present study was aimed to identify which part of the eyestalk of P. pelagicus contains more LF levels in order to establish a specific target part of samples.

MATERIALS AND METHODS: Thus, crab samples for this study were sampled from the wild habitat at Setiu wetlands, Terengganu, Malaysia. A total of 100 samples of with the same size (80±5 mm carapace width) were sampled and the eyestalk dissected for LF extraction. The determination of LF sites and levels in the eyestalks organ was taken from the area between the distal tangential layer (DTL) and proximal tangential layer (PTL). The lower part of the eyestalk was taken from the PTL until the end of the eyestalk.

RESULTS: The upper part of the crab's eyestalk was higher in the males crabs compared to the females crabs. LF index also shown that the upper part of crab's eyestalk have higher concentration compared to the lower part.

CONCLUSION: The left crab's eyestalk had the higher LF index especially in males compared to females but the total concentration was higher in female crabs. Knowing which part has highly dense accumulation of LF helps in LF detection of the tissue and further helps for age determination for this species.