The discovery of new species of jellyfish or planktonic cnidarians is not a rare event even in recent years, as they are often found in the deep-sea or offshore waters where most of us, even scientists, are unable to access. However, it would be surprising if a large, conspicuous jellyfish, consumed by people was new to science. A new species of
jellyfish that has been commercially harvested for more than 20 years for human consumption was discovered recently in central Java, Indonesia.

This new scyphozoan jellyfish, Crambionella helmbiru, belongs to the genus Crambionella, the family Catostylidae, and order Rhizostomeae. The specific name is derived from ‘helm biru’, meaning ‘blue helmet’ in Bahasa Indonesia, referring to the beautiful blue colour of its body and the nickname by which it is known to local fishermen ‘ubur-ubur helm’ (helmet jellyfish). Three species were formerly recognized in the genus, i.e. C. annandalei, C. orsini, and C. stuhlmanni. Those Crambionella jellyfish are known to occur in the Arabian Sea, the Indian Ocean and the Red Sea. In 2002–2003, for example, mass occurrences of C. orsini were reported in the Gulf of Oman and the Persian Gulf, and large aggregations of dead jellyfish, thought to be this species, have been observed on the seafloor deposited within canyons and on the continental rise and are considered to contribute significantly to the annual downward flux of organic carbon in that area.

We originally found this species in Karang Duwur, Kebumen central Java, Indonesia in September 2008 during our investigations on jellyfish fisheries in Southeast Asia. We conducted further detailed research the following year to obtain sufficient specimens for study. Together with detailed measurements on morphology, we also applied molecular analysis to clarify the genetic differences with closely-related species, concluding that the harvested species was previously undescribed. The resulting paper was a unique mixture of the description of the species together with a description of the fisheries for the species Nishikawa et al. (2015).

Edible jellyfish (C. helmbiru) are landed and transferred to the processing factory in Cilacap, central Java, Indonesia. Image: Nova Mujiono.

Jellyfish have been used as food at least since 400 AD in China. According to FAO statistics, the amount of world production in jellyfish reached 30–50,000 metric tons in recent years: the values are higher than those for scallops or lobsters. In Southeast Asia, more than eight species of rhizostome jellyfish have been commercially harvested in Thailand, Indonesia, Malaysia, Vietnam and other countries. They are caught by various kinds of fishing gear including set-nets, driftnets, hand-nets, scoop-nets, beachseines, and hooks. These fisheries are characterized by large fluctuations in monthly or annual catch, and a short fishing season (typically a few months). Commercial jellyfish fisheries are generally small-scale and we have relatively limited knowledge about them, for example how and when the fishermen operate, how much is caught, and how the jellyfish are processed into commercial products for human food.

The discovery of this new species of commercially harvested jellyfish is considered important not only for its contribution to taxonomy, but also for the conservation of species diversity as well as the sustainability of fisheries targeting this species.

Jun Nishikawa

FURTHER READING
Kramp, P. L. (1961) Synopsis of the medusae of the world. Journal of the Marine Biological Association of the United Kingdom, 40, 1-469.
Nishikawa, J., et al. (2015) A new species of the commercially harvested jellyfish Crambionella (Scyphozoa) from central Java, Indonesia with remarks on the fisheries. Journal of the Marine Biological Association of the United Kingdom, 95(3): 471-481. DOI:10.1017/S002531541400157X.
Stiasny, G. (1921) Studien über Rhizostomeen mit besonderer Berücksichtigung der Fauna des malayischen Archipels nebst einer Revision des Systems. Capita Zoologica, Deel, 1(2), Pp. 179, 150 figs. on 175 pls.

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Jun Nishikawa

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