Distribution and abundance of larval fishes collected in the western Bransfield Strait region, 1986–87

Larval fishes were obtained from 0-50 m bongo net and stratified 0-200 m Nansen net samples collected in the western Bransfield Strait region during four RACER program cruises, December, 1986, through March, 1987. Three nototheniid species, Nototheniops larseni, Notothenia gibberifrons, and Trematomus scotti, numerically dominated the total catch. Two typically abundant species in this area, Pleuragramma antarcticum and Notothenia kempi, were relatively uncommon. Depth related catch differences appear to be responsible for substantial shifts in species abundance relations between the two types of net hauls. Gear differences, the restricted geographical coverage, and between year variability in hydrographic conditions may explain species dominance differences between the RACER samples and prior surveys in the Antarctic Peninsula area.
Largest abundances occurred during January in the vicinity of Gerlache Strait and island shelf areas; larvae were infrequently collected in Drake Passage waters. Individual species demonstrated different distributional patterns suggesting that water mass influence, larval depth distribution, and behavioral differences may be involved.
Estimated January-March growth rates for Nototheniops larseni (0.06 mm day-1) and Trematomus scotti (0.05 mm day-1) are similar but low compared to that of Notothenia gibberifrons (0.12 mm day-1).