COMPARATIVE ANALYSIS OF THE MINERAL COMPOSITION OF SEAWEED EXTRACT Sargassum sp. AND FERMENTED TRASH FISH TO ASSESS THEIR SUITABILITY AS A LIQUID FERTILIZER

Seaweeds and trash fish are rich in macronutrients and micronutrients. In Gulf of mannar coast, brown seaweed of Sargassum sp is the major stranding seaweed which are underutilized. The landings in the fishing harbour located in Thoothukudi (8.7884° N, 78.1592° E),  produces trash fish contributes more than 20% from by catches and it is considered as major environmental problem. Against this background, the present study was aimed utilize the seaweeds and the trash fish to develop organic liquid seaweed extract and fermented trash fish fertilizer respectively to be used in fish ponds to  enhance plankton productivity as an alternative to inorganic fertilizer.

Seaweed extract was prepared (Rama rao ,1990) and fermentated for 4 weeks. Fish fertilizer was prepared by mixing the trash fish with jaggery and fermented for 14 days(Vincent etal. 2014). Nutrient was analysed for both seaweed extract and fermented trash fish in ICP-OES instrument.

The results showed that both seaweed extract and trash fish have enough macro and micro nutrients that they are suitable to be used as organic fertilizers. Their decreased pH prevents their spoilage during storage. In trash fish phosphorus level is more(63.86 mg/l) than seaweed extract( 2.26 mg/l) it indicates that fermented trash fish can be used as a fresh water organic fertilizer, since phosphorus is a freshwater limiting nutrient. Though, both seaweed extract and fermented trash fish have both macro and micronutrients, it theortically shows that combination of both seaweed extract and fermented trash fish are recommended for complete organic fertilizer.