Feeding ecology, prey selection and growth performances of gold spot mullet, Liza parsia (Hamilton, 1822) in extensive brackish water farming system of Indian Sundarbans

A study was aimed to focus on the feeding ecology with prey selection and growth performances of gold spot mullet ( Liza parsia) in extensive polyfarming system. Three ponds (0.7-0.9 ha) were brought under observations which continued for 10 months (January- November, 2015). Estuarine water containing wild fry of various species were allowed to enter in three impoundments. Commercial feed or fertilizer was not applied following common practice. Exchange of 20-30% water was carried out during lunar cycles. Water temperature and water depth were average 29.90C and 120 cm. Order of dominance of prey groups in water was chlorophyceae, bacillariophyceae, myxophyceae, copepod and dinoflagelats. Tendency towards higher feeding intensity in terms of stomach fullness was observed as the fish grew. Order of dominance of prey groups in stomachs were myxophyceae, chlorophyceae, bacillariophyceae, dinoflagelatsand copepods while myxophyceae followed by bacillariophyceae was actively selected. Copepods were selected for first two months and negative selection of all zooplankton groups were noticed afterwards. L. parsia attained 58.94±2.02g (15.2±0.19cm) at harvest with slope value of length-weight relationship (b=3.028) and condition factor (K=1.26±0.11).Good growth and health condition in the present study can be attributed to the low production farming system with comparatively lower stocking density providing greater food and space for the growing fish. Keywords: Liza parsia; feeding ecology; prey preference; growth; Extensive farming; Sundarbans