Reports on the impact of Caulerpa lentillifera by alien free-living isopod Paracerceis sculpta (Crustacea, Isopoda, Sphaeromatidae)

Abstract

Unidentified free-living isopods (Crustacea, Sphaeromatidae) occurring in an important commercial seaweed bed of Caulerpa lentillifera at Miyako-jima island, southern Japan, are identified herein Paracerceis sculpta (Holmes, 1904) originating from the pacific coast from California to Mexico. This species has been reported as an alien species the world. The impact of P. sculpta on growth of C. lentillifera was observed for a week in laboratory aquaria, by comparison to control aquaria without isopods. No negative impact on the growth on the alga was observed except on already injured C. lentillifera exposing to mature P. sculpta. This shows usually that P. sculpta does not utilize C. lentillifera as its main food but usually feeds on other materials.