Abstrakt

Zooplankton in the Gut Content of Indian Shad (Tenualosa ilisha): Case Study at the Meghna River Estuary, Bangladesh

Afroza Akter, Muhammad Arifur Rahman, Sarfo Isaac* and Md. Jahangir Sarker

The Indian Shad or Hilsa (Tenualosa ilisha) is the national fish of Bangladesh. The study was conducted to identify zooplankton species in the gut content of Hilsa, collected from the Meghna river estuary in two seasons: pre-monsoon (March) and monsoon (June) in 2014. Fishes (N=80) were divided into four different groups as per their body weight (i.e. <75 g, 76-150 g, 151-225 g and >225 g). Relative length of gut (RLG) of the four groups were 1.10 ± 0.04, 1.19 ± 0.04, 1.35 ± 0.02 and 1.44 ± 0.02, respectively. The study identified twenty six (26) zooplankton species under six (6) groups comprised of copepods (50.04%), cladocerons (23.10%), protozoans (11.55%), chaetognatha (8.33%), rotifers (4.83%) and ostracods (2.15%). Zooplankton abundance was higher in pre-monsoon and lower in monsoon. However, density (individuals/100 ml) of zooplankton in gut content of the Hilsa decreased with the increase of the size. The study suggested that at the young stage of life cycle, Hilsa mainly feed on zooplankton and diverts their food habits they grow. The study could be very helpful for the ethical and ecosystem-based management and optimum utilization of this single largest valuable Hilsa fishery in Bangladesh