The present study describes the length-weight relationships (LWRs) of four Acetes species (Acetes indicus, A. serrulatus,
A. japonicus and A. sibogae) which were sampled from offshore trawling and inshore catches along the west coast of
Peninsular Malaysia. Morphometric measurements (total length, TL and wet weight, WW) were obtained from the samples
and LWRs were estimated. All LWRs were significant (p<0.05) for the four species, with the coefficient of determination, R2
>
0.659. The estimated b values for LWR were 2.432-3.403. The R2
value was >0.84 when the data was analysed according
to inshore and offshore samples. Male and female A. indicus and A. serrulatus demonstrated negative allometric growth
whilst male A. japonicus and A. sibogae showed isometric growth type. Positive allometric growth was depicted by a
combined group of male and female A. sibogae. This study has contributed to the knowledge of the offshore and inshore
distribution patterns of different populations of Acetes spp. in the Straits of Malacca. It also presents a comparison of
the LWRs between offshore and inshore catches of A. indicus and A. serrulatus, with the inshore catches of A. japonicus
and A. sibogae, which have not been previously reported. The findings of this study would contribute to the conservation
and management of this commercially important fisheries resource.
The intra- and inter-specific variation of Acetes shrimps were evaluated based on samples collected from in-shore catches and off-shore trawling around the west coast of Peninsular Malaysia. Species captured were identified as Acetes indicus, A. serrulatus, A. japonicus and A. sibogae. A region of the mitochondrial cytochrome c oxidase subunit I (COI) gene comprising 552 base pairs (bp) was amplified from 159 Acetes specimens. The sequence alignment analysis generated phylogenetic trees which depicted the four major clades that were consistent with the species identified morphologically. These four species varied considerably for haplotype and nucleotide diversity, with A. indicus and A. serrulatus showing different demographic histories. Furthermore, the observation of two clades in the A. indicus and A. sibogae lineages, with relatively high levels of intraspecific divergence, suggests that cryptic diversity is possibly present in these two taxa. This study has contributed to the knowledge of the distribution patterns and molecular phylogenetics of four Acetes spp. in the Straits of Malacca.