Clarke,-R.D.  Effects of microhabitat and metabolic rate on 
	food intake, growth and fecundity of two competing coral 
	reef fishes.  CORAL-REEFS. 1992. vol. 11, no. 4, pp. 
	199-205.

Spinyhead blennies (Acanthemblemaria spinosa ) and roughhead 
blennies (A. aspera ) are planktivorous hole-dwelling fishes 
that live in dead coral skeletons. Both species are known to 
choose shelters high above the reef surface. To test the 
hypothesis that this preference is due to greater plankton 
availability in higher locations, fish were placed on 
artificial habitats located 15 cm and 100 cm above the 
surface of a natural reef. Both species experienced higher 
feeding rates, growth rates, and fecundities in high 
locations, and spinyhead rates generally exceeded roughhead 
rates at a given height. It is hypothesized that spinyheads 
have an advantage in agonistic interactions because of their 
higher metabolic rates, thus excluding roughheads from high 
sites, but that roughheads can persist at low sites because 
their lower metabolic rates result in lower food demands. A 
model is presented that predicts varying occurrences and 
vertical distributions of these species in locations with 
different zooplankton densities.