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

Abstract

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 holothuriansʼ 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.

Millepora spp. as Substrates of Their Hydrozoan Counterparts Stylaster sp. in the Pacific Ocean

“…Both organisms belong to groups of hydrozoans that calcify, namely the families Stylasteridae Gray, 1847 and Milleporidae Fleming, 1828 [7]. In the biodiverse marine ecosystems of the Ryukyu Archipelago, several unexpected interactions between different taxa have been reported [8][9][10], and some of these associations have been found to be widespread despite having remained unreported for a substantial amount of time [11]. Here we report our observations of the association between Millepora spp.…”