Predator-prey relationships between the rock lobster Jasus lalandii and the mussel Aulacomya ater at Robben Island on the Cape West Coast of Africa

An Estimate of Production and Consumption Rates in the Spiny Lobster Panulirus homarus on a Shallow Littoral Reef off the Natal Coast, South Africa

“…While the density and biomass of Panulirus homarus on the OR1 Reef are somewhat higher than have been recorded in other members of the genus Panulirusthey are substantially lower than those recorded for Jasus lalandii by Pollock (1979). J. lalandii is, however, a comparatively slow growing, long-lived cold water species which could be expected to accumulate a high biomass in conditions of low mortality rate provided that adequate food and shelter are available which, according to Pollock (1979) is the situation at Robben Island.…”

“…J. lalandii is, however, a comparatively slow growing, long-lived cold water species which could be expected to accumulate a high biomass in conditions of low mortality rate provided that adequate food and shelter are available which, according to Pollock (1979) is the situation at Robben Island. A high production rate of 30.3 g m-2y-' for males and 2.8 g m-*y-' for females (wet mass) has been recorded for J. lalandii by Pollock (1978) compared with equivalent values of 6.9 g rn-2y-' and 5.1 g m-'y-', respectively for P. homarus.…”

“…If this is substantial it is probable that Smale's (1978) consumption rates in which individually separated mussels were fed under calm tank conditions are overestimated. Nevertheless, it is considered unlikely that food availability limits the standing crop or growth rate of lobsters on the OR1 Reef, particularly in view of the substantially higher mean biomass of Jasus lalandii supported by a lower biomass of mussels (Pollock, 1979).…”

“…The availability of food to these mussels and hence their productivity is dependent in both cases on physical energy subsidies. In A. ater this is largely the southeasterly wind which upwells nutrient rich water resulting in plankton blooms (Pollock, 1979), while in the case of P. perna it is the wind-driven surf action in the littoral zone which ensures the availability of detritus as food (Berry, 1978). It is suggested that a reason that the stocks of P. homarus are smaller than those of J. lalandii may lie in the fact that the energy subsidy on which P, perna and consequently P. homarus are dependent is present over the restricted area of the nearshore zone.…”

Seasonal changes in depth distribution, sex ratio and size frequency of spiny lobster Jasus edwardsii on a coastal reef in northern New Zealand

“…McKoy & Leachman (1982) found dense aggregations of ovigerous females at the deep seaward edge of coastal reefs. In other palinurid species variations in the abundance of particular sizes and sex among depth, season and site have been reported (Kanciruk & Herrnkind 1973, Mercer 1975, Davis 1977, Pollock 1979, Herrnkind 1980, Kanciruk 1980, Lyons et al 1981, Pollock 1982.…”