Croatian Journal of Fisheries (Mar 2004)
APPLICATION OF THE GREAT CORMORANT'S (Phalacrocorax carbo sinensis) DAILY MEAL IN THE STIMATION OF DAMAGES AT FISHPONDS
Abstract
Daily meal of the Great Cormorant (Phalacrocorax carbo sinensis), joined with the number of birds and composition of fish in the meal, has high importance in total calculation of damage-costs on fish stock. The weight of fish in daily meal is regarding as the world-wide indicator for the estimation of damages. Various methods are being developed for the reliable estimation of daily fish quantity that Cormorant consummate. Diversity of the applied methods lead to variability of the results. This paper presents the estimation results from 24 studies. Daily meal of the Great Cormorant determined by the stomach content analysis is 359.5 g in average per bird (n=3 study reports); by the pellets analysis 347 g (n=10) is determined, and mean weight values of regurgitated fish was 384 g (n=2). Analyses of the nourished, captured birds (n=4) show 371 g mean value of daily meal while the stomach temperature method show 336 g (n=1 study). The energy requirement methods determined daily meal of 596 g (n=1, a study dealing on the empirical basal metabolism measurements), and 751 g (n=3, studies dealing on daily energetic requirements of the Great Cormorant).
