Environmental Biology of Fishes

, Volume 9, Issue 3–4, pp 193–223

On the spawning behavior and spawning cycles of eight surgeonfishes (Acanthuridae) from the Indo-Pacific

  • D. Ross Robertson
Full Papers


Surgeonfish spawning was observed at Palau, Lizard Island, Escape Reef (all Pacific Ocean) and Aldabra (Indian Ocean). Seven species, all fairly exclusively benthic feeding, defended feeding territories to some extent, and some of them formed territorial groups composed of 1 male + ≥ 1 female. One other species ate both benthic algae and zooplankton, and both sexes appeared to be nonterritorial, except that males defended temporary spawning territories. The primary spawning rhythm appeared to be a restriction of spawning to part of the day. Ebb-tide spawning rhythms were evident where distinct tidal currents flowed on and off a reef: at one such site (Palau), a secondary tidal rhythm of spawning overlaid and combined with the primary rhythm to produce an apparent semi-lunar rhythm of spawning. Peaks of spawning of three Palauan species were on days when tidal heights/amplitudes were either less than or no different from the mean. Fishes that lived in intertidal areas (including some from heterosexual territorial groups) migrated to and massed and spawned at the intertidal/subtidal interface. Some fishes spawned in pairs, either in their (intertidal and subtidal) feeding territories or in temporary spawning territories at the reef edge. Many that migrated to the reef edge were (temporarily) nonterritorial there, and spawned in groups [I female (sometimes more?) + many males]. Predatory fishes and zooplanktivorous fishes attacked spawning fishes and fed on fresh ova. At Palau, egg predators attacked group, rather than pair spawnings. Pulses of massed group spawning may reduce the rate of egg predation per group spawning. Two different types of color change by both sexes were associated with the two basically different patterns of spawning — in pairs and in groups.


Migrations Diel tidal and semi-lunar rhythms Predator-prey interactions Color changes 


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Copyright information

© Dr W. Junk Publishers 1983

Authors and Affiliations

  • D. Ross Robertson
    • 1
  1. 1.Smithsonian Tropical Research InstituteBalboaRepublic of Panama

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