Isso Kelp Forest

Isso on Yakushima's northern coast sits in the cooler upwelling shadow of the island's 1,936 m central peaks, where the Kuroshio Current is deflected and surface temperatures drop enough for Ecklonia kelp forests to establish. The kelp canopy at 5 to 18 m is dense and seasonally dynamic — lush and tall from winter through spring, thinning in the warmest summer months. Beneath the canopy the substrate is volcanic rock encrusted with coralline algae, nudibranchs, and sea urchins. Japanese morwong (Goniistius zonatus) and wrasse species endemic to southern Japan forage through the kelp. Cephalopods — bigfin reef squid and Japanese pygmy squid — are resident year-round. This is one of very few subtropical kelp forest dive sites in Japan and the southernmost reliable kelp diving in the country.