Resumen de Biometric Indices of Four Crustaceans and Two Mangrove Fishes From Coastal Waters in Bangladesh

Md Robiul Hasan, Abdullah Al Mamun, Md Yeamin Hossain

• Many crustaceans and commercial fish species are considered to be essential aquatic resources of Bangladesh coastal waters. However, a little is known regarding biometric indices, e.g. length-frequency distributions (LFDs), length-weight relationships (LWRs), and relative-condition (KR) factors of those crustaceans and fishes, which is vital for conservation and management. Our study investigated LFDs, LWRs, and KR of total 227 individuals (covering 5 families), including 173 individuals of four crustaceans (Macrobrachium rosenbergii, Metapenaeus monoceros, Exopalaemon styliferus and Scylla serrata) and 54 individuals of two fish species (Pomadasys argyreus and Caecula pterygera). The LFD for crustaceans exhibited that the lowest and highest total length (TL) was 5.9 cm for E. styliferus and 23 cm for M. rosenbergii, respectively. Besides, the LFD for fishes showed that the lowest and highest TL was 13.46 cm for P. argyreus and 58.51 cm for C. pterygera. The b (allometric co-efficient) values of studied species ranged from 2.02 (P. argyreus) to 3.22 (C. pterygera) and found to be highly significant (P < 0.001). Additionally, the average KR values for crustaceans and fishes were 0.925 and 1.045, respectively, suggesting the condition of the population was good. Moreover, this is the first evidence regarding LWRs and KR for E. styliferus, P. argyreus and C. pterygera, which would be beneficial for conservation scientists and updating the online database (SeaLifeBase and FishBase). Our findings should be conducive for the protection and sustainable management of crustaceans and fishes from coastal waters in Bangladesh and neighbouring countries