Variability in the location of the retinal ganglion cell area centralis iscorrelated with ontogenetic changes in feeding behavior in the black bream, Acanthopagrus butcheri (Sparidae, Teleostei)

The development of neural cell topography in the retinal ganglion cell laye r was examined in a teleost, the black bream (Acanthopagrus butcheri). From Nissl-stained wholemounts, it was established that fish between 10 and 15 mm standard body length (SL) possess high cell densities throughout the dor so-temporal retinal quadrant, with peak cell densities located in temporal regions of the retina. However, in fish between 15 and 80 mm SL, a wide var iation in the position of the peak cell density is revealed with the locati ons of the areae centrales (AC) ranging from exclusively temporal to periph ero-dorsal retina. Fish larger than 80 mm SL always possess an AC located i n the dorsal region of the dorso-temporal retinal quadrant. The topography of ganglion cells within the ganglion cell layer was determined by comparin g the numbers of ganglion cells retrogradely-labeled from the optic nerve w ith the total population of Nissl-stained neurons (ganglion plus displaced amacrine cells) in a range of different-sized individuals. Ganglion cell to pography was the same as that recorded for all Nissl-stained neurons. The f eeding behavior of juveniles from metamorphosis to 80 mm SL was observed, w here fish were given the choice of feeding on live food in mid-water (until 15 mm SL) or obtaining pellets from the surface or the bottom, A range of feeding patterns was recorded, with the smallest fish taking food from mid- water but individuals between 15 and 80 mm SL taking food either from the s urface or the bottom or both, A correlation between the preferred mode of f eeding and the position of the AC was found, such that those individuals fe eding in mid-water or at the surface possess a temporal or intermediate (do rso- temporal) AC, whereas those predominantly feeding from the bottom poss ess a dorsal AC, Copyright (C) 2000 S. Karger AG, Basel.