AGE-SPECIFIC MORTALITY-RATES IN REEF FISHES - EVIDENCE AND IMPLICATIONS

Mortality is a fundamental demographic rate, the nature of which has p rofound consequences for both the dynamics of populations and the life -history evolution of species. For example, if per capita mortality ra tes are age-or stage-specific, life-history traits should evolve in re sponse to age-and stage-specific differences in selection arising from these temporally variable rates. Similarly, variation in the average mortality rate across ages and/or stages can also select for shifts in life history. Mortality rates of recently sealed reef fishes can be v ery high and per capita mortality is commonly assumed to decrease with increasing age. A review of evidence for age-specific per capita mort ality rates in reef fishes from early postsettlement up to 13 months p ostsettlement suggests that during this period these rates are often a ge invariant. The data on which these interpretations are based, howev er, are extremely limited both in terms of the proportion of the life cycle over which mortality rates have been sampled and the quality of these data. Nonetheless, these data do suggest that selective pressure s associated with patterns of mortality may vary among species of reef fishes and that these species therefore could be more effectively use d in the study of life-history evolution. At present, reef fishes are under-represented in the study of life-history evolution compared with other vertebrate taxa.