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.
Yeungs
Mastigias papua - 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].
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 genetic 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.
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Richard Stovall
Stomolophus meleagris - common name - Cannonball Jellyfish
It is possible that sightings of this species in SE Asia have been misidentified from other species [1]. This medium-sized species can grow up to 18 cm wide, with a milky yellow or bluish color, leading down to a brown margin of the bell. It eats zooplankton and is preyed upon by sea turtles and sun fish [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].
Naomi Bousson
Pelagia panopyra (noctiluca) -
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.
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.
Other species known to be present in Hong Kong waters
These species have been seen in Hong Kong waters, or are acknowledged to be present by the Hong Kong Register of Marine Species, a node on the World Register of Marine Species (WORMS). 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!!
Edie Hu
Rhopilema hispidum - common name - sand jellyfish or flower jellyfish
This large-sized scyphomedusa, measuring up to 70 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. Very common in Hong Kong waters. 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}.
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.
Divya Rao
Lobonema smithii
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 rarely seen in Hong Kong waters. Reported to cause severe stings [1]..
© 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. There are three species of crystal jellyfish recorded in Hong Kong waters - A. macrodactylus (photo), A. pensilis, A. parva [9]. 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.
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.
Josy Lai
Beroe cucumis [8] - common name - comb jellyfish
This species is in the phylum Ctenophora and is not considered a "true" jellyfish. It has rows of cilia (hairs) that it uses for locomotion It 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.
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.