Chirodropid box jellyfish in the Gulf of Thailand

Abstract

© 2018 Senckenberg Gesellschaft für Naturforschung and Springer-Verlag GmbH Germany, part of Springer Nature Numerous severe and fatal cases of jellyfish stings have been reported from the Gulf of Thailand, and chirodropid box jellyfish have been suspected to be responsible for them. Despite the severity of these envenomations, only a few studies have been conducted on the jellyfish in this region. In order to establish a chirodropid database in Thailand, marine biologists and officers from four Marine and Coastal Resources Research and Development Centers set out to investigate the distribution patterns of chirodropids across 15 provinces along the Gulf of Thailand from November 2009 to February 2016. More than 1500 chirodropid individuals representing three species, Chironex indrasaksajiae, Chironex sp., and Chiropsoides buitendijki, were documented. The season when the highest numbers of chirodropids were found was July to September. Specimens of Chironex spp. were only collected from Surat Thani province (9° N from the equator) and northward, whereas specimens of Chiropsoides biutendijki exhibited a broader distribution but were less numerous than Chironex spp. north of 9° N. When combining life-threatening and fatal cases with the distribution patterns of chirodropids, the severe and fatal cases took place only in the area where Chironex spp. appear. The locality where most chirodropids were collected was Surat Thani province, one of the most important touristic destinations in Thailand.