TOPOGRAPHIC AND HYDROGRAPHIC EFFECTS ON CATCH RATES OF AUSTROGLOSSUS-PECTORALIS (SOLEIDAE) ON THE AGULHAS BANK

Catch rates of Agulhas sole Austroglossus pectoralis from research tra wls were compared with depth of sea bed, bottom temperature and oxygen concentration. Data were from 10 research surveys conducted during th e years 1986-1992 in autumn and spring. Cold bottom water situated bet ween Mossel Hay and St Francis Bay separated two zones of warmer botto m water on the inner central and eastern Agulhas Bank in both seasons. Low to zero catch rates were associated with the cold water, whereas catch rates were higher in warmer water, especially at depths shallowe r than 75 m. On the inner central Agulhas Bank, catch rates close insh ore were considerably higher in autumn than in spring. Conversely, on the eastern Agulhas Bank, catch rates were higher over a larger area i n spring than in autumn. Depth of sea bed explained 23-49% of the vari ability in catch rates within localities and seasons, whereas bottom t emperature and oxygen concentration had lesser effects.