CHRONIC AFFECTS OF DETERGENT SURFACTANT (LINEAR ALKYLBENZENE SULFONATE / LAS) ON THE GROWTH AND SURVIVAL RATE OF SEA BASS (Lates calcalifer Bloch) LARVAE

Abstract

Sea bass (Lates calcalifer Bloch) is one of the economically important marine fishes, which is getting more important for marine-culture. This fish is categorized as a euryhaline species, i.e. has a wide salinity tolerance range. This species can live in the sea with salinity between 32 – 35 ppt, and in the river, estuarine and mangrove areas with the salinity between 0 – 25 ppt. The adult sea bass spawn in marine waters and the larvae and juvenile are mostly found in the estuarine. Estuarine is known as a good nursery and feeding ground, however it is also known as a pollutant trap. Therefore, the larvae of seabass and other euryhaline species are very susceptible to this condition Surfactant detergent Linear Alkyl-benzene Sulfonate (LAS) is a non-ionic soft detergent, which has a long straight carbon chain and a powerful cleaning capability. It is toxic to aquatic organisms, and however it is biodegradable. Therefore, it is widely used for cosmetic and household purposes. Some research found that the toxicity (LC50-96 hours) of LAS detergent on invertebrate Daphnia magna was 2.7 mg/l, on gastropods was 19.4 mg/l and on shrimp (Panaeus japonicus) was 4.5 mg/l. The acute and chronic effect of this detergent on tropical marine fish is not yet known. This research was done to find out the chronic effect (LC50-96 hours) and acute effects, of detergent LAS on the larvae of sea bass (Lates calcaliver Bloch). A Bioassay method was applied to find out the acute toxicity, and Probit Analyses was used to find out the LC50-96 hours of detergent LAS on sea bass larvae. Randomized Design was used to observe the chronic effects on the growth, survival rate of the sea bass larvae. There were six treatments applied, i.e.: treatment A (0% of LC50-96 hours); B (5% of LC50-96 hours); C (10% of LC50-96 hours); D (15% of LC50-96 hours); E (20% of LC50-96 hours); F (25% of LC50- 96 hours). Analyses of variance were used to find out if there was a significant different in the treatment, followed by Multiple Range Duncan Test to find out the different among treatments. The histology of the gill and liver of the sea bass exposed to different concentration of detergent LAS was also observed. The results showed that the LC50-96 hours of detergent LAS on sea bass larvae was 1.18 mg/l and considered as moderately high toxicity. The absolute biomass growth of sea bass larvae was not affected by sub-lethal concentrations of detergent ALS, however, chronic concentrations of detergent LAS affected the daily growth rate of sea bass larvae significantly (p<0.01). As a conclusion, the acute toxicity of LAS detergent on sea bass (Lates calcaliver Bloch) larvae was 1.18 mg/l. The sub-lethal concentrations of detergent LAS on the sea bass larvae did not influence the biomass growth and survival rate but affected the daily growth rate of sea bass larvae significantly. The sea bass larvae exposed to the sub lethal concentrations of LAS detergent for 30 days resulted in the gill damage, i.e.: hypertrophy, hyperplasia, telengeastases and melanization of the gill. The congestion and vacuolar degeneration of the liver were also observed.