A thick brown sea cucumber of Galapagos rock and sand, heavily fished in the past and slow to recover.
Averages 23 cm and about 390 g, reaching 40 cm and 830 g. Elongate and curved, dark brown, spotted with orange papillae.
Within the Galapagos it is distinct enough, but Isostichopus identification generally is complicated by colour variation, so colour should be treated as a genus-level cue.
Nought to forty metres, preferring three to thirty, on rocky reef. It is listed as Endangered.
The fishery history is the reason it matters. Fishing began on mainland Ecuador in 1989 and the mainland stock collapsed by 1991, at which point the fishery moved to the Galapagos. A brief legal reopening in 1994 set a quota of half a million animals; between eight and twelve million were taken in one season. Catch per diver-hour fell from 103 to 55 between 1999 and 2005. San Cristobal and Santa Cruz closed in 2002, Floreana permanently in 2003, and the whole fishery closed after the 2006 collapse. A five-year moratorium ran from 2016 aiming at eleven animals per hundred square metres as the minimum viable breeding density; monitoring in 2021 found a median of twelve in western Isabela and the fishery reopened that July with a quota of 600,000 over sixty days.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.