Planktonic Larval Duration, age and growth of Ostorhinchus doederleini (Pisces: Apogonidae) on the southern Great Barrier Reef, Australia

Abstract

Cardinalfishes (Apogonidae) are abundant on corals reefs, but there are few data on demography to understand trophodynamics and population dynamics. Ostorhinchus doederleini is a small and abundant apogonid on the Great Barrier Reef (GBR) and throughout the Western Pacific Ocean. We present key demographic parameters for the entire life history from the southern GBR. Daily deposition of increments in otoliths was validated. Fish had a Planktonic Larval Duration (PLD) of 16 to 26 days. PLD was established from fish collected immediately prior to settlement as no settlement mark was found. Fish grew at about 0.35 mm d-1 for the first 20 d after settlement. Fish reached a maximum standard length at about 200 d and no fish lived longer than 368 d at four reefs separated by kilometers to tens of kilometres. There was no evidence for differences in size at age between sexes. Mortality was very high, for fish greater than 60 days old mortality ratesranged from 2.9 to 4.6% per day. Short lives and high mortality rates makes O. doederleini, and potentially other apogonids, vulnerable to recruitment failure. Here we review data on the demographic characteristics of other reef fishes. Although some taxa live to over 50 years, the short lives of apogonids are most aligned with the Gobiidae and Blenniidae (i.e. typically < 1.5 years). Descriptions of fish size, age, longevity, growth and mortality; from hatching to age maxima are very rare for most taxa, even at the level of family.