At 192 hah, all tanks were emptied and survivors were counted. During the experiment, the tanks were siphoned twice a day to remove uneaten food and dead fish. However, larvae of P. hypophthalmus are small (about 0.9 mg at the start of exogenous feeding, at 36 hah), and they undergo a rapid decay in warm water. Hence, many dead fish probably passed unnoticed and the mortality dynamics
could not be traced accurately during this experiment. The knowledge of the mortality dynamics is unimportant in respect to prey density (nauplii per volume unit), whereas it matters for determining the actual number of prey available per survivor, and its consequences on food intake, growth and size heterogeneity. In absence of additional information, daily mortality (M, % day−1) was deemed almost constant throughout the experiment, and was estimated as M=[Ln (Ni)−Ln (Nf)]/6.5, where Ni and Nf are the initial and final numbers of fish in a tank, and 6.5 is the duration of the experiment (days). Thenumber of survivors at a particular age in each tank was estimatedfrom these.