Effect of salinity on survival and growth of Marphysa sanguinea (Polychaeta: Eunicidae) juveniles

Abstract

Today, integrated multi-trophic aquaculture (IMTA) is the way forward in managing waste from aquaculture farms. The identification of Marphysa sanguinea as a potential candidate for this purpose has aroused the need for its commercial artificial production. Meanwhile, there rarely exist studies on the environmental factors affecting its growth and survival. In order to test the hypothesis that salinity affects survival and growth of M. sanguinea, and to determine the range of salinity tolerance and their effect on the species’ survival and growth, 4,500 juveniles of initial weight 0.006 ± 0.0003 g were cultured under controlled conditions. Triplicate groups of worms were reared under five different salinities (15, 20, 25, 30, and 35psu) for 120 days by semi-recirculation system. Oyster shells (70%, 5 mm in diameter) and sand (30%, 2 mm in diameter) were used together as sediment. Survival rate and growth rate were determined, both within and between groups. Both survival and growth were significantly affected by salinity (p < 0.05). Results of this research confirms that M. sanguinea has high tolerance for salinity fluctuation and proves to be an excellent candidate of IMTA for fish species cultured within a salinity range of 20 – 35psu. For optimum survival and growth in commercial production of M. sanguinea, however, 25 psu is recommended.