Ascidians observed associating epizoically on holothurians in waters in the Kerama Islands, Okinawa, Japan

抄録

Photograph records of four holothurian individuals upon which colonial ascidians were associated epizoically are reported from the waters around Akajima Island, Kerama Islands, Okinawa, Japan. Although holothurians are known to be hosts of many organisms, these new observations add a new perspective to understanding the ecological role of holothurians as mobile scaffolds. Some ascidians have limited capabilities of locomotion, but we believe an association with holothurians would increase the mobility of ascidians. On the other hand, such associations may be beneficial as part of the holothurians’ chemical defenses, since some ascidians and/or harbored cyanobacteria produce bioactive compounds. Even though these observed cases may be temporary associations, it is apparent holothurians are ecosystem engineers on coral reefs not only due to their feeding behavior, but also due to their associated fauna.