Crustacean (Malacostraca) plankton assemblages in the northern Bay of Bengal: A comparison of seasonal and geographical patterns


J. Mawa, S. Rana, N. Sultana and Sk.A. Al-Nahid*

The production of wild crustacean larvae is crucial to Bangladesh's emerging shellfish industry. In the coastal zone of the northern Bay of Bengal, Bangladesh, environmental parameters and geographical and seasonal distribution patterns of the Malacostracan plankton stage (Subphylum: Crustacea) were studied. Plankton samples were collected from the surface using a bongo net. During the sampling period, four groups were identified: shrimp larvae, krill, crab zoea, and mantis shrimp larvae. Among them, almost 63% of krill were recorded, followed by shrimp larvae (21.1%), crab zoea (12.4%), and mantis shrimp larvae (3.4%). In addition, krill was the most abundant group at each station and season. One-way ANOVA was conducted to identify significant variation (P<0.05) in the mean larval abundance of crab zoea, shrimp larvae, krill, and mantis shrimp larvae based on the season of each group. A significant difference was observed among shrimp larvae, crab zoea, and mantis shrimp larvae during the season. However, krill abundance was not significantly different between seasons. Univariate analysis of correlations between stations and the abundance of crustacean groups was performed. Pairwise comparisons of mean anbundance showed significant variations between the identified four groups and three stations (Naf, Bakkhali and Rezu Khal estuaries). However, only the mean abundance of krill varied significantly with all the four stations (P<0.05). These results suggest that the abundance of Malacostracan crustaceans did not depend on stations; rather, their abundance varied significantly within seasons in the northern Bay of Bengal.

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