FEEDING DYNAMICS OF THE ARTIFICIALLY RAISED JUVENILE FISH OF OLIVE FLOUNDER PARALICHTHYS-OLIVACEUS AND OCELLATE PUFFER TAKIFUGU RUBRIPES

Feeding activity was investigated for the artificially raised juvenile fish of olive flounder Paralichthys olivaceus and ocellate puffer Tak ifugu rubripes which incurred hunger trials for various time spans. Th ey were fed brine shrimp Artemia salina nauplii programatically every 6 hours, and the time interval between two sequential gulps (GI) was m onitored for about half an hour. Their statistics demonstrated that th e flounder's gulping pitch was susceptible to hunger: it varied the fi ckle attack in the early trials to the periodic one in the late trials with the acceleration of the pitch. On the contrary, the puffer demon strated a shift in mean GI that didn't correlate to the hunger persist ence and stable pitch of any trials, which may mean that the puffer wa s under the control of some other factor than the stimulus of hunger. The stochastic estimates on the gulping number per mean GI for each tr ial typified those of either binomial, Poisson's or negative binomial distribution type. The flounder indicated the succession from negative binomial type (via Poisson's) to binomial. The puffer, on the other h and, nearly conveys Poisson's with one exception. These lend support t o the explanation between hunger persistence and the gulping mode, whi ch is the focus of our research.