The sea urchins Tripneustes ventricosus and Lytechinus variegatus are ecologically and economically important grazers of seagrass beds throughout the Caribbean and Florida. In Jamaica we observed recruitment events of T. ventricosus at the same site and season (January–April) in 2001 and 2002. In 2002 there was a concurrent recruitment of L. variegatus. Following the 2001 recruitment T. ventricosus grew at a rate of 1.2 mm wk^-1 and at relatively low rates (0.6 mm wk^-1) after the 2002 recruitment. The 2002 recruit cohort of L. variegatus also grew at low rates (0.7 mm wk^-1) compared to published values. While densities of T. ventricosus remained relatively stable after the 2001 recruitment, densities of both species declined after the 2002 recruitment. The low growth rates and density decreases after 2002 suggest that the increases in abundances resulting from the 2002 recruitment intensified intra- and interspecific competition among urchins.