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Visual censuses were used to survey shallow-water assemblages of the Lutjanidae and Lethrinidae among three mid-continental shelf reefs, and fish traps were used to survey deeper water assemblages below diveable depths. Significant differences were found in visual censuses of the Lutjanidae and Lethrinidae among reefs. Trap catches of the Lutjanidae and Lethrinidae varied more between depths and diel sampling periods than among reefs or over time. Lutjanus carponotatus, L. fulviflamma and Lethrinus miniatus were more abundant in shallow trap sets, whereas Lutjanus adetii, L. russelli, L. sebae, L. vitta, Gymnocranius audleyi, Lethrinus sp.2 and Abalistes stellaris were more abundant in deeper sets. Additionally, Lutjanus adetii, L. fulviflamma, L. quinquelineatus, L. russelli, L. sebae, L. vitta and Lethrinus miniatus were more abundant at night, whereas Lethrinus sp. 2, Abalistes stellarisand Plectropomus leopardus were more abundant during the day. The absence of significant temporal variation in the observed spatial patterns both among reefs and between depths indicates that these patterns may persist through time. The use of both visual censuses and fish traps to assess reef fish assemblages may provide an objective way of repeatedly censusing reefs for monitoring purposes, especially where differences among reefs and regions are important.

Patterns of piscivory were investigated among five abundant species of predatory fish at One Tree Reef, Great Barrier Reef, Australia. The guts of two lutjanids Lutjanus carponotatus and Lutjanus fulviflamma, two labrids Cheilinus diagrammus and Thalassoma lunare, and a serranid Epinephelus quoyanus were examined for type, length, number and volume of prey at two times of the day: sunrise and sunset. Each of these species consumed fish, but only T. lunare and the two lutjanids consumed recruit-sized fish. This information is important because there is often scepticism as to whether large predators (>200 mm TL) such as lutjanids consume new recruits. Only in the lutjanids were there differences in the number and volume of prey present in the gut at sunrise and at sunset; at sunset, few lutjanid specimens contained prey, whereas at sunrise 98% of specimens contained prey. This result, in conjunction with studies of nocturnal activity, suggest that patterns of predation pressure inferred from daylight observations of predator abundance may have little relevance to actual patterns of predation at local scales.

The hooking mortality of two teleosts, the yellow stripey Lutjanus carponotatus (Lutjanidae), and the wire netting cod Epinephelus quoyanus (Serranidae), was examined for fish captured with lures and bait from shallow waters (

The shedding rate of FD-67 anchor tags from L. carponotatus was significantly lower than that of FT-2 dart tags. Mortality in fish tagged with either the FT-2 dart or the FD-67 anchor tags was significantly higher than in the untagged controls. There was no significant difference between mortalities caused by the two types of tag. Combining tag shedding and tag-induced mortality, the FT-2 dart tag produced a significantly greater rate of disappearance of tagged fish from a tagged population. Tag-induced mortality was highest during the first week after tagging and greatly reduced thereafter.