Filter Feeding of Freshwater Mussel, Ensidens ingallsianusingallsianus, for Water Quality Control in Tilapia Closed Culture System

Abstract

A two-month experiment growing juvenile tilapia with and without freshwater mussel, Ensidens ingallsianusingallsianus, in an outdoor closed culture system without water exchange was conducted to evaluate the possibility of using the freshwater mussel to improve water quality. Average values of turbidity, chlorophyll a, total particulate matter, particulate organic matter, particulate nitrogen,  particulate phosphorus and total ammonia nitrogen were 8.5 NTU, 100.8 µg/L, 14.2 mg/L, 11.5 mg/L, 2.139 mg/L, 0.120 mg/L, and 0.286 mg/L in tilapia with freshwater mussel treatment, compared to average values of 22.0 NTU, 324.1 µg/L, 42.5 mg/L, 34.1 mg/L, 5.291 mg/L, 0.305 mg/L, and 0.599 mg/L in tilapia only treatment. Average values of turbidity, chlorophyll a, total particulate matter, particulate organic matter, particulate nitrogen, and particulate phosphorus in tilapia with freshwater mussel treatment were significantly lower (P< >0.05) than those in tilapia only treatment. However, there was no significant difference (P> <0.05) in the average values of total ammonia nitrogen between the two treatments. Results of this experiment showed that E. ingallsianusingallsianus was effective in removing particulate matter, particulate nitrogen, phytoplankton and particulate phosphorus from water in tilapia culture tanks, resulting in decreased  rates of 61.4% of turbidity, 66.6% of total particulate matter, 66.3% of particulate organic matter, 68.9% of chlorophyll a, 59.6% of particulate nitrogen and 60.7% particulate phosphorus. There was no significant difference (P< >0.05) between production rate, survival rate and growth rate of tilapia in both treatments.