Population biology of Trapezia spp. And other coral-associated decapods

Abstract

We describe the population structure of 3 coexisting species of Trapezia and 4 other common decapod species associated with the reef coral Pocillopora in the Eastern Pacific Ocean. Most species carry eggs throughout the year, and egg number is highly correlated with body size. Trapezia postlarvae (= postmegalopa) recruit in April and June only and reach adult size by the following January. Sex ratios vary among species and may be affected by the frequency of movement among coral heads. Decapod abundance is often higher on the shallow reef flat, where Pocillopora cover is more continuous and predatory fishes are less common. In contrast to many 'community' studies, area (coral head size) is not an important predictor variable, except for a modest effect on abundance. Instead, season and reef location emerge as the most important correlates with population structure of decapod species associated with Pocillopora.