Effect of Different Natural Substrates on Periphyton Production under Earthen Lined Seawater Pond for Periphyton based Aquaculture

Abstract

Background: Periphyton-based aquaculture improves water quality, provides a natural food supplement, limits harmful bacteria, provides a safe haven for shrimp to escape, and adds living space. The impacts of diverse natural substrates on periphyton formation were examined under earthen lined pond seawater systems as a first step in analysing the sustainability of periphyton-based shrimp production. Methods: Natural substrates such as coconut coir, coconut shell and split bamboo pole were placed inside the earthen lined pond filled with seawater for duration of 45 days. Periphyton samples were obtained from each type of substrate on the 15th, 30th and 45th days of the experiment. For all substrates, periphyton biomass and chlorophyll ‘a’ pigment in the periphyton were measured at depths of 0 to 40 cm, 40 to 80 cm and 80 to 120 cm. Physico-chemical parameters of experiment pond water were recorded during periphyton samplings. Result: During the experiment, coconut coir showed higher periphyton biomass in terms of dry matter (DM) (3.4995 0.31201 mg/cm2) and chlorophyll ‘a’ pigment (3.2949 0. 27076 mg/cm2). Duncan’s Multiple Range Test and One Way ANOVA of diverse data reveal a significant difference (P 0.05) between the substrates in periphyton biomass and chlorophyll ‘a’ pigment. In all three substrates, a Student’s ‘t’ test analysis shows that the upper 0 to 40 cm depth yields more periphyton biomass and chlorophyll ‘a’ content than the other levels. Coconut coir was the best natural substrate for periphyton growth among the three.