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Data on early survivorship of newly settled reef fish were collected by monitoring individuals which recruited to 30 small lagoonal patch reefs over three summers. Preliminary survivorship curves spanning the first 45 days after settlement were derived for 17 species. Most species showed greatest rates of mortality in the first 1–2 weeks in the reef environment however there were substantial differences among species in the extent and the temporal pattern of this. In six species, 75% of individuals survived the 45 days, while in 5 others, 20% or fewer survived that long. In eight species, mortality was negligible after the first 14 days. In the other 9, significant mortality occurred in subsequent weeks. Patterns of survivorship did not appear to differ substantially among years in five of the six species for which data were adequate. In particular, survivorship did not appear to be different among years even when levels of recruitment varied greatly.

The densities of recruits on caged and uncaged areas were compared in an experiment done to show the extent of predation on recently metamorphosed coral reef fishes. The design was unlike typical caging experiments, however, in that areas were caged only for short periods of 20–30 days and several independent trials, testing the same null hypothesis, were run. This was done to avoid confounding the effects of excluding herbivorous fishes with the effects of excluding piscivorous fishes. A third treatment, partially-meshed cages, revealed that the experiment was complicated by several other factors. Some prey species were attracted to the high relief offered by the experimental structures. Others responded to the differences in shelter from predators by redispersing themselves among the treatments shortly after settlement. There was also at least one significant “edge” effect caused by fishes preferring to settle near the boundaries of all treatments. In spite of these difficulties, observations on known individuals revealed that rates of mortality were age-dependent and decreased rapidly after metamorphosis. More than 25% of such fishes disappeared during their first five days in the benthic habitat compared with >10% of fishes aged 6–10 days and no losses of fishes aged 11–15 days. These early losses are the greatest instantaneous rates of mortality yet documented for recruited reef fishes. The experiment also suggested different rates of early mortality for various groupings of species: individuals of solitary, sedentary species disappeared approximately half as fast as individuals of the more mobile, and the more gregarious, species. This is probably a true reflection of the different vulnerability of these groups to predation and it may be caused by the different ways in which these fishes use the coral substratum. Our experience suggests that caging artifacts can have major impacts on the results obtained from this type of experiment and they must be controlled for adequately. We conclude that studies of predation on reef fishes may be done more easily using other methods.

A set of small lagoonal patch reefs was searched every 1 to 3 days during the peak recruitment seasons of three summers and newly settled juvenile fishes were located. The majority of species remain rather sedentary during the first few days in the demersal environment, and we assumed that the site occupied was the site chosen at settlement. A series of characteristics of the occupied site were recorded, including percent cover of different types of substratum, and attributes related to the site's position on the patch reef. A set of null sites was randomly located on the same reefs for comparison with those selected by the fish. Sites chosen by individuals of eight common species were compared with these null sites, and sites chosen by fourteen species (including the eight) were compared with each other. Multiple discriminant analysis was used to assess the degree to which each species selected a unique type of site, and, for the eight species, the degree to which sites chosen by fish could be discriminated from randomly selected sites on the same patch reefs. Chosen sites were readily discriminated from null sites in seven of eight species, however the procedure was poor at discriminating among sites chosen by different species, and 8 pairs of species among the 14 chose sites which on average did not differ in the attributes measured. Attributes most important in discriminating sites chosen by each species are considered. Overall, the results indicate that while juvenile fish do not settle indiscriminantly onto lagoonal patch reefs, sites chosen by different species are often not very different from one another.