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Changes in reef benthos were assessed at Aldabra Atoll following the mass coral bleaching event of 1998. Video transects were used to survey the benthos and analysed using the Australian Institute of Marine Science five-dot method. Comparison of coral cover data collected by the Cambridge Southern Seychelles Atoll Research Programme with data collected during this study revealed that mortality of coral at Aldabra following the bleaching event was approximately 66% at 10 m depth and 38% at 20 m depth. Five years on, there are signs of hard coral recovery at some locations, but in spite of several years of high coral recruitment (7-9 recruits per m2 at 10 m depth, 4-6 recruits per m2 at 20 m depth, where recruits are defined as any colony under 5 cm maximum diameter), recovery of hard coral has not occurred at a significant level. There has been a considerable increase in soft coral cover at some locations, which was dominated by the genus Rhytisma. Macro algal cover did not increase following the bleaching event, although, as would be expected, dead corals have been colonized by coralline algae. There have been no further events leading to large-scale coral mortality at Aldabra since 1998.

SynopsisResearch on eleven artificial reefs in Puget Sound, Washington examined the relative importance of reefproduced prey items to recreationally important reef fish species assemblages. The colonization of potential prey items, and fish species assemblages to ten artificial reefs were examined for the reefs first two to five years, and observations were conducted on an eleventh reef during its forty-ninth productive year. Fish species became more abundant, or were seen more frequently on reef habitats whose substrates had successionally developed from barnalces to algal mats. Fish species most affected by this successional change foraged heavily on organisms which were associated with reef algae. Starfish and nudibranchs, who preyed on the barnacles, were identified as the 'keystone' predators of these subtidal reef habitats.

A model for natural mortality over the 18 mo of marine life of Puget Sound coho salmon (Oncorhynchus kisutch) is proposed, wherein the natural mortality rate M continuously decreases with increasing weight. Weight closely follows an increasing exponential function of marine age. The model is extended to account for ocean troll and sport fishing mortality and applied to data from marking studies of Puget Sound coho. The survival curve for marine life with only natural mortality declines rapidly for early ocean life and is quite flat over the ages fished. Recent high survival rates for hatchery coho released at a larger than normal size could be partially explained by this mortality model, although additional marking experiments are needed to separate the effects upon survival of size at release and time of release. The model applied to hatchery release-size strategy indicates that 70 g/fish might be optimal.