DAILY GROWTH RATES OF Chaetoceros sp. CULTURED IN MEDIA DILUTED USING DIFFERENT SOURCES OF FRESHWATER

Ike Trismawanti, Agus Nawang and Muhammad Hafid Masruri
 
 Research Institute for Coastal Aquaculture
 Jl. Makmur Dg. Sitakka No. 129, Maros, South Sulawesi,
 Indonesia, 90512
 ic_ast@yahoo.co.id

Phytoplankton as natural feed required optimum salinity for its growth under laboratory scale. Distilled water is a common source of freshwater to dilute sea water for optimum salinity for phytoplankton growth; however, the availability of distilled water, particularly in some remote area remains a drawback. Therefore, there is a need to explore alternative source of freshwater to maintain optimum salinity for natural feed under laboratory scale. This study was aimed to analyse the impacts of different sources of freshwater on Chaetoceros sp. growth.This study was conducted in Research Installation for Black Tiger Shrimp Hatchery, Barru Regency, Province of South Sulawesi. Sea waters were diluted with freshwater of air conditioner outlet (Treatment A), artesian well (Treatment B), commercial refill water (Treatment C) and distilled water as control (Treatment D). The diluted waters then poured in to 2 L of transparent glass then Chaetoceros sp. was inoculated to all glasses.  One-Way ANOVA was applied to analyse the differences in inoculated Chaetoceros sp. in all treatments.

The results of this study indicated that the growth rates of inoculated Chaetoceros sp. cultured under all treatments shows a similar trend. Low growth rates of Chaetoceros sp. were observed within the first two days of culture before reaching their peak at the third day of culture. The growth rates of Chaetoceros sp. in all treatments were stagnant before declining at the end study periods. The results of statistical analyses indicated that the abundance of Cheatoceros sp. in all treatments were no significantly different. These findings indicated all alternative sources of freshwater be able to substitute the distilled water. This study, highlights contaminant-free freshwaters should be use in diluting sea water for phytoplankton culture under laboratory. Thus, freshwater treatment should be conducted prior to sea water dilution.