To elucidate which environmental factors affect lagoonal‐scale sea cucumber distributions in Ishigaki Island, Okinawa, Japan, intertidal and subtidal areas of three coral reef lagoons were classified into several ground divisions by bottom characteristics, and sea cucumber densities therein were compared with the composition of sediment cover, grain size and organic content, and coverage of macroalgae, seagrass, and massive corals. Holothuria atra, Holothuria leucospilota, Stichopus chloronotus, and Synapta maculata had highest densities in the nearshore areas but were rare in reef flats, probably because of wave disturbance and low areal cover of sand sediment as potential feeding environments. No relationship was observed between sea cucumber densities and sediment organic content or grain size. Thus, even if these sea cucumbers have selectivity for habitats with a high sediment organic content, the effect of such selectivity on the distribution seems to be limited to relatively small areas. The sea cucumber distributions can be classified by bottom sediment/biota composition into bedrock (H. leucospilota), sand (H. atra), and lagoonal types (St. chloronotus and Sy. maculata). These habitat selections were possibly related to various aspects of sea cucumber ecology such as refuge from predators or turbulence, or settlement and nursery place, which have implications for importance of the complexity of lagoonal‐scale topography and sediment/biota conditions for the coexistence of various holothurian species.

中文翻译：

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日本南部石垣岛周围珊瑚礁泻湖和附近水域中海参的分布与沉积物特征的关系

为了阐明哪些环境因素影响了日本冲绳岛石垣岛泻湖尺度海参的分布，根据底部特征将三个珊瑚礁泻湖的潮间带和潮下带区域划分为几个地面分区，并比较了其中的海参密度和沉积物覆盖，颗粒大小和有机物含量，以及大型藻类，海草和块状珊瑚的覆盖率。甲壳纲（Holothuria atra），白斑全鳞菌（Holothuria leucospilota），绿巨嘴St（Stichopus chloronotus）和斑突触藻（Synapta maculata）在近海地区密度最高，但在礁滩中却很少见，这可能是由于波浪扰动和作为潜在觅食环境的沙沉积物的地表覆盖率低。海参密度与沉积物有机物含量或粒度之间未发现任何关系。因此，即使这些海参对具有较高沉积物有机含量的生境具有选择性，但这种选择性对分布的影响似乎仅限于相对较小的区域。海参的分布可以通过底部沉积物/生物区系组成分为基岩（H. leucospilota），沙（H. atra）和泻湖类型（St. chloronotus和Sy。maculata）。）。这些栖息地的选择可能与海参生态学的各个方面有关，例如来自掠食者的庇护所或湍流，或定居和苗圃地，这对于泻湖尺度地形的复杂性和沉积物/生物区系条件对于各种共存的重要性具有重要意义。全人类。