Features Research
Taiwanese researchers test algal diets on tropical copepod

In a recent paper (Aquaculture Research, 2012, 1–13) Jiang-Shiou Hwang of the Institute of Marine Biology, National Ocean University, Keelung, Taiwan, and his colleagues Yen-Ju Pan; Sami Souissi; Anissa Souissi; Cheng-Han Wu; and Shin-Hong Cheng, describe a series of experiments that examined the potential of the calanoid copepod Acartia bilobata as a live food for tropical marine fish larvae.

Copepods are commonly used as live feeds in the aquaculture industry, and several species of Acartia, the natural prey of many fish larvae, are considered an optimal live feed for marine larval fish. A. bilobata in particular is easy to culture in bulk and thus has excellent potential as a food source for hatchery-bred marine fish larvae. Their study investigated the effects of a series of algal diets, singly and in combination on the egg production and -hatching rate of A. bilobata.

Of the three phytoplankton species studied, the results indicated that the single-species diet of Isochrysis galbana was the most supportive for A. bilobata egg production and female life span (egg production: 23.85 ± 0.70 eggs per female per day, and female life span: 18.00±1.45 days). Nannochloropsis oculata and Tetraselmis chui diets yielded markedly lower egg production and female life span when fed singly and in combination. In the egg hatching-rate experiment, except for the T. chui diet, which yielded a considerably lower hatching rate, the hatching rate under the different diets was only slightly affected.

Overall, the results showed that the tropical brackish-water copepod A. bilobata grows and matures rapidly at 28°C and can produce a large number of eggs; and has considerable potential for larvae culture.

For more information contact J.S Hwang at: jshwang@mail.ntou.edu.tw.

– DJS