Hong Kong Jellyfish Species Information
The Agriculture Fisheries and Conservation Department (AFCD) records 6 species of jellyfish that have been found in Hong Kong waters - Cyanea nozakii, Mastigias papua, Aurelia aurita, Stomolophus meleagris, Pelagia panopyra and Acromitus flagellatus. Information on each species is below. There is still much that is not known about each species, so everyone's contributions can count!
There are numerous species with distribution around the world that are likely to be found in Hong Kong waters. Help HKJP to find them and report your sighting!
Ryan Yue Wah Chan
Cyanea nozakii - common name: Ghost jellyfish
This pelagic species can be found throughout the Indo-West Pacific: China, Japan and Myanmar, west Thailand and west Indonesia [1,2]. This medium to large sized medusa is generally milky white to light brown and can reach up to 120 cm wide. Little is currently known about its feeding and stings, though there are reports of nematocysts on the exumbrella. Often referred to locally as "Lion's Mane", this species is responsible for many of the stings that occur in Hong Kong waters, due to its long trailing tentacles. The most commonly reported species of jellyfish in Hong Kong and widely distributed in local waters.
Nick Thompson
Mastigias papua (albipunctatus) - common name: Papuan spotted jellyfish
This medium-sized species can be found throughout the Western Pacific, from Japan to the Indian Ocean and Red Sea. It can grow up to 8 cm wide and has been found in multiple color combinations, blue-green to brown-green, with white spots [1]. It contains symbiotic zooxanthellae from which it gets energy, so performs diel vertical migration [2]. It also consumes zooplankton, phytoplankton, small invertebrates, and microbes [2]. More recent research has divided this species into three species, while historically there have been up to eight. The species considered to be in the Hong Kong area is Mastigias albipunctatus [3]. Seen individually throughout Hong Kong.
Millie Basden
Aurelia aurita - common name: Moon jellyfish
This genus has different forms that may be different species across the world, yet are difficult to tell apart. It is one of the most common species of jellyfish around the world. A. aurita can be up to 40 cm wide, with a color ranging from white, rose to blueish or even colorless. The sting is so mild that it is frequently not felt. This species feeds on zooplankton and fish larvae [1]. It provides fatty acids and macronutrients to the fish and crustaceans that prey upon it [2]. Known to form huge swarms in the summer months. Through DNA analysis, it is possible that the species of Aurelia present in Hong Kong may not be A. aurita or there may be more species present. Common in Hong Kong, usually seen from July onwards.
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Richard Stovall
Stomolophus meleagris - common name: Cannonball jellyfish
Sightings of this species in SE Asia have been misidentified from another species, Nemopilema nomurai [1]. An early recording of S. meleagris in Hong Kong came from "The sea shore ecology of Hong Kong" by Morton and Morton (1983), though more recent information puts its range around the Americas. This is given support by a genetic study that found the species in Chinese waters matches Nemopilema nomurai (common name: Nomura's jellyfish) [4]. Earlier researchers misidentified Nemopilema nomurai due to nomenclature confusion between Japanese and Western scientists [12]. So far, mainly recorded from Morton and Morton (1983).
Top image is Stomolophus meleagris - found around the Americas.
Bottom image is Nemopilema nomurai - found around Japan and China seas.
Pelagia panopyra (noctiluca) - common name: Mauve stinger
P. panopyra - common name Sea Nettle. P. noctiluca common name - Mauve Stinger
The species P. panopyra is considered doubtful and is likely to be P. noctiluca [6]. This small scyphomedusa has a diameter of 5-10 cm and feeds on copepods, fish eggs and zooplankton [1]. It can produce bioluminescence when it is disturbed. The sting of this jellyfish can be strong. This species is rarely seen in Hong Kong.
Atim Lau
HKJP
Acromitus flagellatus - common name: River jellyfish
This medium-sized scyphomedusa, with a bell up to 12 cm [1], can be found across the western Indian Ocean to the central Pacific Ocean [5]. It can be found in mangroves and estuaries [2]. This species is known to form large blooms and local populations have been discovered. It is regularly seen in Hong Kong; in large numbers in Tolo Harbour in 2021 and in Discovery Bay in 2023.
Other species known to be present in Hong Kong waters
These species have been observed in Hong Kong waters by citizen scientists who shared their sightings with the Hong Kong Jellyfish Project. Some of these species are not considered "true" jellyfish (medusa with bell), but are included in a broader definition of "jellyfish" in Brotz el al. (2012). Their definition of ‘‘'jellyfish' refers to gelatinous zooplankton that include medusae of the phylum Cnidaria (scyphomedusae, hydromedusae, cubomedusae, and siphonophores) and planktonic members of the phylum Ctenophora" [7].
Please let the HKJP know about any jellyfish you see to add to this record!!
Scyphozoa - There are around 200 described jellyfish species in the class Scyphozoa or "true jellyfish". This number is changing as the study of jellyfish genetics is updating their taxonomy and more species are being discovered. Sometimes what researchers once thought of as a single species may be divided into many more species.
Edie Hu
Rhopilema hispidum - common name: Sand jellyfish or Flower jellyfish
This large-sized scyphomedusa, measuring up to 80 cm across in locally stranded individuals, can be found across the Indian Ocean to the western Pacific Ocean [2]. It earns the name “sand jellyfish” from the granular texture of the umbrella. Stings swimmers and surfers with shorter tentacles leaving a different pattern than Cyanea nozakii. This jellyfish has many commensal species associated with it - several species of fishes, a shrimp, a crab, a copepod, and a flatworm {2}. Very common in Hong Kong waters.
Kevin Leung
Lobonema smithii - common name: Hairy jellyfish
This large-sized scyphomedusa, up to 50 cm in diameter, ranges from the Indian Ocean to the Philippines [1]. This species has distinctive finger-like projections coming from the top of the bell with stinging cells upon them, unlike most other jellyfish species that have a smoother bell [1]. Although it is considered one of the edible jellyfish, it is reported to cause severe stings [1]. It is rarely seen in Hong Kong. An infrequent visitor to Hong Kong, it was seen more frequently in 2022 by several divers.
Josy Lai
Anomalorhiza shawi
Very little is known about A. shawi because of a lack of observations and reports in the scientific literature. First described from a specimen in Manila Bay, Philippines, it is thought to range from Hawaii, through Malaysia and the Philippines, into Hong Kong waters [13] and beyond into the waters around Thailand. There is no information currently known about its diet, life cycle and stings, however it is known be a host to some fish, crabs and brittle stars [14]. This species has been seen a couple of times in Hong Kong waters.
Sonny Wong
Cephea cephea - common name: Purple crown jellyfish
This medium-sized crowned jellyfish looks quite similar to Netrostoma setouchianum, however has long whitish filaments that trail from the oral arms, that are lacking in Netrostoma [1]. First described in the Red Sea, Cephea cephea ranges across the Indo-Pacific northwards to Japan [1]. Although Hong Kong is within in the known range of this species, it has been reported only once by citizen scientists.
Wai Hong Yiu
Netrostoma setouchianum
This large scyphomedusa was first described in and named for the Setouchi-Umi, in the Inland Sea of Japan [1]. It has been seen in the seas near India, eastward to Australia and north to Japan [15]. Like Cephea cephea, little is known about its diet and stings, though two types of caridean shrimps are known to associate with them [16]. It is an infrequent visitor to Hong Kong.
WIllie San
Thysanostoma loriferum - common name: purple jellyfish
This medium-sized scyphomedusa is found from the Red Sea across the Indo-Pacific to Hawaii. It is a pelagic species, infrequently seen, and little is known about its life cycle, associations or diet [1]. This species has been reported only twice in Hong Kong waters, both times along the eastern side.
Cyanea purpurea
This species' range is originally thought to be from the north end of Japan to the coast of Russia [1], however there are references to it in the scientific literature as far south as Xiamen, China [17]. This species looks very similar to Cyanea nozakii, the more common species in Hong Kong, however, for citizen scientists, the purple color can help to differentiate. Other internal features not readily visible to citizen scientists differentiate the species. This species was seen in Hong Kong in large numbers only in the spring of 2022.
Joe Cheung
Chrysaora chinensis - common name: Malaysian sea nettle
This medium-sized scyphomedusa has a bell diameter up to 15 cm across [1]. It can be found across the western Indo-Pacific Ocean - China, Indonesia, Philippines, Sumatra [11]. Was confused with C. melanastor but recent taxonomy has confirmed it as its own species. It may be a coastal species and little is known of its diet [1]. It has a severe sting. Infrequently seen in Hong Kong, anecdotally seen more in late summer, early autumn.
Ctenophora - Comb jellies are not considered "true jellyfish", however a included in the general "jellyfish" or "gelatinous plankton" groups. Comb jellies have lines of cilia (hairs) that they use for locomotion. Ctenophores can be found in all oceans of the world. Of around 150+ species of ctenophores, only three have been regularly reported in Hong Kong. They are difficult to see clearly and identify, also showing up in large groups that could obscure different species.
Josy Lai
Beroe sp. - common name: comb jellyfish
This species is cosmopolitan, found throughout the world's oceans from shallow to deep water. It does not sting and envelopes its prey within its cavity to consume it. Comb jellies are bioluminescent. Fairly common in Hong Kong, especially in spring, and shows up with large numbers.
Janice Ma
Pleurobrachia globosa - common name: Sea gooseberry
Pleurobrachia globosa can be found around the Western Pacific. Their distinctive feature is the two long trailing tentacles they use to capture prey by swirling in loops. It can be found in high abundance in Chinese seas [18]. The abundance and distribution of P. globosa in Hong Kong is unknown.
Josy Lai
Ocyropsis crystallina
This species is one of the lobed ctenophores. Normally used for feeding, the lobes can also be used to propel the ctenophore away from predators [19]. Its abundance and distribution in Hong Kong is unknown.
Cubozoa - There are approximately 50 species of cubozoans world-wide, though new ones are being added, such as Tripedalia maipoensis, a new Cubozoan species described in 2023, found in Hong Kong! There is little known about other box jellyfish in Hong Kong waters, though citizen scientists submitted sightings of two other box jellyfish species in 2021 and 2022.
Tripedalia maipoensis - common name: Mai Po box jellyfish
This species is an exciting discovery as it was first described in Hong Kong in 2023 by researchers at WWF Mai Po, Ocean Park, Hong Kong Baptist University, and the University of Manchester [20]. Box jellyfish are thought to have a small range [21], so it is possible that this is a Hong Kong-specific box jellyfish. More research is needed into its biology and ecology.
Calvin Tang
Malo filipina
This medium-sized box jellyfish comes from the Philippines [1] and is a single observation by a diver in Hong Kong. It is not known the mechanism by which it came to Hong Kong or if there will be an established population. Its sting is said to be severe [1].
Kevin Leung
Morbakka (probably M. virulenta) - common name - Giant boxjelly
This large-sized box jellyfish is from Japan. The bell of this jellyfish can be up to 25cm high and 20cm wide [1]. It has not been reported in Hong Kong waters before several citizen scientists' reports in 2022 and 2023. Also in early 2022, pieces of jellyfish collected in Sham Wan, Lamma Island were tentatively IDed by DNA analysis as Morbakka sp. More research is needed into the presence of Morbakka in Hong Kong.
Hydrozoa - Of the 3700 species of hydrozoans, only just over 60 of them have been recorded in Hong Kong’s waters. They tend to be smaller in size and can be difficult to spot for citizen scientists. They come in an amazing variety of different body types and arrangements. Check out some of the great diversity of the class that can be found in Hong Kong!
Two common hydrozoa are below:
Dennis Leung
Aequorea spp. [10] - common name: Crystal jellyfish
These hydromedusa can range in size from a couple of centimeters to 10 cm across or larger, depending on species. It can be difficult to identify species of Aequorea accurately due to overlapping variability in their morphology. One species of Aequorea was used to synthesize a Green Fluorescent Protein which is used in biomedical research. They are naturally bioluminescent. There are three species of crystal jellyfish recorded in Hong Kong waters - A. macrodactylus (photo), A. pensilis, A. parva [9].
HKJP
Porpita porpita - common name: Blue button
This is a colonial hydroid, meaning that it is made up of individual zooids, all performing different tasks. It can be found around the world in warmer tropical and sub-tropical waters. Porpita porpita is a frequent visitor to Hong Kong, usually washing up in very large numbers. Mild to negligible sting.
Many hydrozoans are very small, under a few centimeters and are very difficult to see. A big thank you to the blackwater divers who have spotted these hydrozoans and shared their photos with the HKJP!
Liriope tetraphylla
Photo: Dickson Wong
Aglaura hemistoma
Photo: Wai Hong Yiu
Solmundella bitentaculata
Photo: Wai Hong Yiu
Leuckartiara octonema
Photo: Atim Lau
Amphinema rugosum
Photo: Atim Lau
Nausithoe punctata
Photo: Atim Lau
Siphonophores are not "true" jellyfish (Scyphozoa), however are frequently included in the larger general category of "gelatinous plankton". They are a separate Order under the Class Hydrozoa and like some other Hydrozoans, they are composed of individual zooids that perform specialized functions, working together to form a colony. There are approximately 175 species of siphonophores in the world, though only a few of them have been spotted in Hong Kong waters.
Physalia physalis
Photo: Andrew Bridle
Agalma okenii
Photo: Wai Hong Yiu
Muggiaea atlantica
Photo: Wai Hong Yiu
Forskalia cf. tholoides
Photo: Atim Lau
Rhizophysa sp.
Photo: Wai Hong Yiu
References:
1. Jarms, G. & Morandini, A.C. (2019). World Atlas of Jellyfish. Dölling und Galitz Verlag, 816p.
2. SeaLifeBase (2020). Retrieved August 10, 2020, from https://www.sealifebase.se/search.php
3. Souza, M., & Dawson, M. (2018). Redescription of Mastigias papua (Scyphozoa, Rhizostomeae) with designation of a neotype and recognition of two additional species. Zootaxa, 4457, 520–536. https://doi.org/10.11646/zootaxa.4457.4.2
4. Zhang, 张姝 Shu, Zhang, 张芳 Fang, Liu, 刘媛 Yuan, & Cui, 崔朝霞 Zhao-Xia. (2009). Molecular identification of two macro-jellyfish in China. Oceanologia et Limnologia Sinica, 40(1), 8.
5. Collins, A. G.; Jarms, G.; Morandini, A. C. (2020a). World List of Scyphozoa. Acromitus flagellatus (Maas, 1903). Accessed through: World Register of Marine Species at: http://marinespecies.org/aphia.php?p=taxdetails&id=220489 on 2020-12-06
6. Collins, A. G.; Jarms, G.; Morandini, A. C. (2020b). World List of Scyphozoa. Pelagia panopyra Péron & Lesueur, 1810. Accessed through: World Register of Marine Species at: http://marinespecies.org/aphia.php?p=taxdetails&id=220477 on 2020-12-06
7. Brotz, L., Cheung, W., Kleisner, K., Pakhomov, E., & Pauly, D. (2012). Increasing jellyfish populations: Trends in Large Marine Ecosystems. Hydrobiologia, 690, 3–20. https://doi.org/10.1007/s10750-012-1039-7
8. Claudia Mills. https://faculty.washington.edu/cemills/Ctenophores.html
9. Schuchert, P. (2021). World Hydrozoa Database. Aequorea Péron & Lesueur, 1810. Accessed through: Astudillo, J. C.; Williams, G. A.; Leung, K. M. Y.; Cannicci, S.; Yasuhara, M.; Yau, C.; Qiu, J-W.; Ang, P. O.; To, A. W. L.; Shea, S. K. H. (Eds.) (2021) Hong Kong Register of Marine Species at: http://www.marinespecies.org/hkrms/aphia.php?p=taxdetails&id=116998 on 2021-11-23
10. Claudia Mills https://faculty.washington.edu/cemills/Aequorea.html
11. Morandini, A., & Marques, A. C. (2010). Revision of the genus Chrysaora Péron & Lesueur, 1810 (Cnidaria: Scyphozoa). Zootaxa, 2464(2464), 1–97.
12. Omori, M., & Kitamura, M. (2004). Taxonomic review of three Japanese species of edible jellyfish (Scyphozoa: Rhizostomeae). Plankton Biology and Ecology, 51(1), 36–51.
13. Ricca, P. M. C., & Cheung, H. C. A. (2021). Sighting of the rare jellyfish Anomalorhiza shawi Light, 1921 in a marine protected area of Hong Kong. Check List, 17(2), 701–707. https://doi.org/10.15560/17.2.701
14. Chuan, C., Venmathi Maran, B. A., Yap, T. K., Cheong, K. C., Syed Hussein, M. A., Saleh, E., & shau hwai, T. (2020). First record of jellyfish Anomalorhiza shawi Light, 1921 (Cnidaria: Scyphozoa) and its associated organisms in Sabah, Malaysia. Regional Studies in Marine Science, 101232. https://doi.org/10.1016/j.rsma.2020.101232
15. Terenzini, J., & Falkenberg, L. J. (2022). First records of the jellyfishes Thysanostoma loriferum (Ehrenberg, 1837) and Netrostoma setouchianum (Kishinouye, 1902) in Hong Kong waters. Check List, 18(2), Article 2. https://doi.org/10.15560/18.2.357
16. Ohtsuka, S., Kondo, Y., Iwasaki, S., & Hayashi, K. (2011). Caridean shrimps associated with the rhizostome jellyfish Netrostoma setouchiana in the central part of the Seto Inland Sea, Japan (in Japanese). Bulletin of the Hiroshima University Museum, 3, 1–6.
17. http://www.cqvip.com/qk/90949a/201501/663912121.html
18. Wang, S., Zhang, G., Zhou, K., & Sun, S. (2020). Long-term population variability and reproductive strategy of a northward expanded ctenophore Pleurobrachia globosa Moser, 1903 in a temperate bay, China. Journal of Experimental Marine Biology and Ecology, 533, 151457. https://doi.org/10.1016/j.jembe.2020.151457
19. Gemmell, B. J., Colin, S. P., Costello, J. H., & Sutherland, K. R. (2019). A ctenophore (comb jelly) employs vortex rebound dynamics and outperforms other gelatinous swimmers. Royal Society Open Science, 6(3), 181615. https://doi.org/10.1098/rsos.181615
20. Sun, Y., Tsui, J. H. Y., Wong, R. T. H., Cheung, R. N. C., Ng, M. K. P., Or, C. K. M., & Qiu, J.-W. (2023). A New Species of Box Jellyfish (Cnidaria: Tripepalidae: Tripedalia) from Hong Kong, China. Zoological Studies, 62(17). https://doi.org/10.6620/ZS.2023.62-17
21. Kingsford, M., Schlaefer, J., & Morrissey, S. (2021). Population Structures and Levels of Connectivity for Scyphozoan and Cubozoan Jellyfish. Diversity, 13(4), 174. https://doi.org/10.3390/d13040174