Rhizostoma pulmo explained

Rhizostoma pulmo, commonly known as the barrel jellyfish,^[1] the dustbin-lid jellyfish or the frilly-mouthed jellyfish, is a scyphomedusa in the family Rhizostomatidae. It is found in the northeast Atlantic, and in the Adriatic, Mediterranean Sea, Black Sea and Sea of Azov. It is also known from the southern Atlantic off the western South African coast and into False Bay.^[2] They are found typically in late summer, and early fall in increased populations which are known as blooms. This is due to higher temperatures and other environmental factors such as wind.^{[3] [4] [5]}

It is common in the Irish Sea. It typically is up to 40cm (20inches) in diameter, but can exceptionally reach 150cm (60inches) or larger,^{[6] [7]} making it the largest jellyfish in British and Irish waters (Cyanea capillata reaches an even larger size, but is generally smaller in Britain). On 13 July 2019, wildlife biologist Lizzie Daly dived off the coast of Cornwall in the United Kingdom, along with the underwater cinematographer Dan Abbott.^[8] The two divers shared their encounter with a human-sized barrel jellyfish, Rhizostoma pulmo. The species could typically grow up to one meter (3.2 feet) and weigh up to 25 kilograms (55 lbs). However, they are not larger than the lion's mane jellyfish.^[9]

Rhizostoma pulmo is moderately venomous but not as deadly as other species. Effects include a burning sensation on the skin, dermatitis, and ulcers which confirms it is toxic to humans. However, it does not pose a serious threat to humans.^[10]

It is a favourite food of the leatherback turtle.^[11]

In Asia, they are a source of bioactive compounds used in traditional food and medicine.^[12] One study indicates that washing in aqueous solutions and the separation of high molecular weight proteins from the extract, e.g., by membrane filtration, could be a way to remove possible toxic compounds from jellyfish extracts and to concentrate potentially bioactive soluble compounds. The potentially active soluble components may have uses as nutraceutical and cosmeceutical ingredients.^[13]

External links

• • • Giant jellyfish the size of a human spotted by divers off English coast (video)
• Barrel Jellyfish, article at Atlas Obscura, August 9, 2021

Notes and References

1. [Aquarium of Genoa]
2. Branch, G.M., Branch, M.L, Griffiths, C.L. and Beckley, L.E. 2010. Two Oceans: a guide to the marine life of southern Africa
3. Dönmez . M. A. . Bat . L. . 2023 . Distributions of Rhizostoma Pulmo (Macri, 1778) between the Kızılırmak and the Yeşilırmak coast of the Black Sea, Türkiye . Oceanological and Hydrobiological Studies . 52 . 3 . 273–286 .
4. Leoni . V. . Molinero . J. C. . Meffre . M. . Bonnet . D. . 2021 . Variability of growth rates and thermohaline niches of Rhizostoma Pulmo’s pelagic stages (cnidaria: Scyphozoa) . Marine Biology . 168 . 7 . 1–19 .
5. Reyes Suárez . N. C. . Tirelli . V. . Ursella . L. . Ličer . M. . Celio . M. . Cardin . V. . 2022 . Multi-platform study of the extreme bloom of the barrel jellyfish rhizostoma pulmo (cnidaria: Scyphozoa) in the northernmost Gulf of the Mediterranean Sea (gulf of trieste) in April 2021 . Ocean Science . 18 . 5 . 1321–1337 .
6. Web site: Rhizostoma pulmo, barrel jellyfish.
7. Web site: Massive, Human-Size Jellyfish Stuns Divers off the Coast of England. .
8. News: Divers 'humbled' by giant jellyfish encounter. BBC News. July 17, 2019.
9. Web site: Humans Who Swam Along a Human-Sized Jellyfish. 17 July 2019. Mirror Herald. https://web.archive.org/web/20190720135721/https://mirrorherald.com/humans-who-swam-along-a-human-sized-jellyfish/. 20 July 2019. dead.
10. Mariottini . Gian Luigi . Pane . Luigi . Mediterranean Jellyfish Venoms: A Review on Scyphomedusae . Marine Drugs . 4 April 2010 . 8 . 4 . 1122–1152 . 10.3390/md8041122 . 20479971 . 2866479 . free .
11. Web site: COAST : Community of Arran Seabed Trust - Barrel Jellyfish. www.arrancoast.com. 29 May 2018. https://web.archive.org/web/20180529203510/http://www.arrancoast.com/education/local-marine-species/102-barrel-jellyfish-rhizostoma-octopus. 29 May 2018. dead.
12. Omori . Makoto . Nakano . Eiji . Jellyfish fisheries in southeast Asia . Hydrobiologia . 1 May 2001 . 451 . 1 . 19–26 . 10.1023/A:1011879821323 . 6518460 .
13. De Domenico . Stefania . De Rinaldis . Gianluca . Paulmery . Mélanie . Piraino . Stefano . Leone . Antonella . Barrel Jellyfish (Rhizostoma pulmo) as Source of Antioxidant Peptides . Marine Drugs . 2019 . 17 . 2 . 134 . 10.3390/md17020134 . 30813405 . 6410228 . free .