Populations of two starfish, Protoreaster lincki and Pentaceraster horridus, were studied during May 1976 in the Marine National Park of Seychelles. The relative abundance of the two species was in a ratio of nine P. lincki to one P. horridus. Size distributions of the two species showed a major mode at m. 12.5 cm for P. lincki and at ca. 14.0 cm for P. horridus. There also were smaller individuals of P. horridus than P. lincki present suggesting that P. horridus may grow faster and not live as long as P. lincki.

Male P. lincki were smaller than females but sufficient data were not gathered to determine whether this was also true for P. horridus. On May 8.17% of P. lincki in the sample spawned. None spawned on 16 May which may indicate the end of the natural spawning season. Some P. horridus spawned in each sample.

Of 245 P. lincki examined, seven had abnormal arm numbers : six had six arms and one had seven. All 27 P. horridus had five arms.