Damselfish territories: zones of high productivity on coral reefs

Abstract

Temtories of 4 species of herbivorous damselfish from coral reefs of the central Great Barrier Reef and Motupore Island, Papua New Guinea were shown to be zones of high algal biomass and primary productivity relative to surrounding epilithic algal communities. Productivity was rneasured in the field from die1 patterns in oxygen flux, employing in situ data-logging respirometers. Algal communities inside territories were 1.6 to 3.4 times more productive per surface area than surrounding algal substrata. Algal communities of damselfish territories maintain a rate of productivity per unit biomass 1.5 to 3.4 times h g h e r than that of algae growing outside the territories. Differences in primary productivity for the 2 different types of algal community are due to the higher photosynthetic efficiency (0.37 to 0.94 pg O2 PE-') and potential maximum rate of photosynthesis (57 to 249 pg Oz cm-2 h-') of algae from territories compared with algae of non-territory areas (0.20 to 0.35 pg O2