Evaluation of Balance between Fishes and Available Fish Foods in Multispecies Fish Culture Ponds in Taiwan

Abstract

Evaluation of the condition of balance between fishes and available fish foods in impoundments of multispecies fish culture in Taiwan was made by analyzing the quantitative interrelations between the standing crop of fish-food biota and the stocked fishes of ecologically different species in a 6-hectare pond with organic fertilization and feeding, and 99 irrigation reservoirs with a total water surface area of 697 hectares. In a balanced condition, the growth rate of plankton, macrophytes, benthos and nekton (exclusive of stocked fishes) kept pace with the rate of consumption by the fishes, respectively, of planktophagic, macrophytophagic, benthophagic, and nektophagic species within the impoundment. Studies of the interaction between the fishes and the fish-food biota in the two types of impoundments of multispecies fish culture with different management methods shed considerable light on fish food utilization and competition in pond ecosystems. On the principle of fish production, these studies provide a basis for improved management of impoundments.