The effects of future consumption by the Cape fur seal on catches and catch rates of the Cape hakes. 1. Feeding and diet of the Cape hakes Merluccius capensis and M. paradoxus

Estimates of diet composition and daily ration for the Cape hakes off the South African west coast are updated with information on stomach contents collected during demersal trawl surveys carried out between 1988 and 1994. The estimates of evacuation rates used for Cape hake stomach content analyses are updated using a model of the stomach evacuation process and data for juvenile Cape hake and other gadoids. The estimates of evacuation time are notably larger than those used in earlier analyses, suggesting that the time 10 evacuate 90% of a prey item ranges from 2 to 10 days depending on the meal size and the size of the predator. The daily ration of the shallow-water M. capensis is estimated to lie between 1,1 and 4,4% of body mass and that for the deepwater M. paradoxus between 0,7 and 4,1% of body mass. Smaller hake constitute an important component of the diet of larger hake, hake constituting up to 50% of the diet of some age-classes. Both hake species are cannibalistic and M. capensis feeds on M. pa...