Marine Invertebrates of Bermuda Purple-striped jelly (Pelagia noctiluca) By Lauren Thomas and James B. Wood and Abel Valdivia(Eds) Abstract  Taxonomy  Habitat  Ecology  Recent Research  Commercial Importance  Bermuda Laws  Personal Interest  References  Links

Abstract


Pelagia noctiluca is a jellyfish found in Bermuda and throughout warm and temperate waters. This species has two common names: the purple-striped jelly and the mauve stinger. It is pink to purple in color and can cause painful stings to swimmers. In Bermuda (as well as other locales), swarms of these jellies occasionally wash onshore, particularly in the winter. In Latin, “pelagia” means open ocean, “noct” means night, and “luc” means light, indicating that P. noctiluca lives in the open ocean and glows in the dark (bioluminescence). Most of the time they are found in the halocline and pycnocline area, although they migrate vertically in response to daily zooplankton migrations. P. noctiluca feeds primarily on macrozooplankton and spend most of their time searching for food. Like all jellyfish, they have stinging nematocyst cells which they use in food capture and defense. Their primary predators are fish. The life cycle of P. noctiluca is unusual for a Scyphozoan in that it has no polyp stage but instead is motile for its entire life. P. noctiluca has no commercial value, so it is not endangered by humans.

Taxononmy


Phylum: Cnidaria
  Class: Scyphozoa
    Order: Semaeostomeae
      Family: Pelagiidae


Habitat


Pelagia noctiluca has a wide distribution in all warm and temperate waters and is found in Bermuda (Sterrer 1986), the Mediterranean Sea (Goy et al. 1989), the Adriatic Sea (Malej 1989), off the coast of California (Fox & Millott 1954), and in the Atlantic Ocean (Larson et al. 1991). Like all Scyphozoans, P. noctiluca is exclusively marine, inhabiting mostly coastal waters (Sterrer 1986).

P. noctiluca forms actively swimming aggregations (Malej 1989) and is usually found in the upper level of the halocline and pycnocline, peaking at a depth of 12 m (Graham et al. 2003) to 30 m (Zavodnik 1987). In Bermuda, P. noctiluca is usually found offshore, but aggregations may drift inshore, especially during winter months (Sterrer 1986). Offshore aggregations rarely contain more than 20 individuals per cubic meter, but inshore swarms can have up to 600 individuals per cubic meter (Zavodnik 1987).

Ecology


Appearance

Medusae of P. noctiluca are pink to purple in color, having blue, brown, and magenta pigments (Fox & Millott 1954). The medusa is filled with an abiotic gel-like substance called the mesoglea. P. noctiluca has 8 tentacles, which can reach up to 10 m in length, and four large oral arms (Sterrer 1986). The tentacles, oral arms, exumbrella, and gastric pouches are covered in cnidocytes, cells that eject a toxin-filled stinging thread (Rottini Sandrini & Avian 1989). P. noctiluca has 16 stomach pouches and 16 lappets, which are foldings of the exumbrella (Sterrer 1986). The exumbrella is covered with wart-like clusters of stinging nematocysts (Burke 2002). The average size of P. noctiluca is 6.5 cm diameter across the bell (Sterrer 1986) but they may grow to be 10 cm or more.

P. noctiluca is well-known for its beautiful luminescence. If disturbed, it will bioluminesce, and this luminescence is often seen at night. It is not certain what causes luminescence in P. noctiluca, but it is not caused by cytolosis (Heymans & Moore 1924) or muscular contraction (Moore 1926). The bioluminescence is likely controlled by the nervous system (Moore 1926); however no recent work has been done on this particular species to confirm this hypothesis. Jellyfish do not have complex eyes, but they do have light receptors called ocelli so they can likely perceive luminescence in conspecifics.

Reproduction and Development

Scyphozoans are dioecious, and the medusae reproduce sexually to form planula larvae. At one time it was thought that sexual reproduction of P. noctiluca occurred only in summer and autumn, but they have been shown to reproduce year round (Rottini Sandrini & Avian 1991). Living in aggregations makes it easy for the jellies to locate sexual partners (Malej 1989). Unlike most scyphozoans, P. noctiluca has no sessile polyp stage (Goy et al. 1989). Instead, the planula larva develops directly into the ephyra stage, which grows to become a medusa (Rottini-Sandrini & Avian 1983).

Feeding

P. noctiluca feeds primarily on macrozooplankton (Malej et al. 1993). Microzooplankton, particulate organic matter, and dissolved organic matter do not seem to be important food sources for these jellies (Malej et al. 1993). They are known to feed on a variety of organisms including Cladocera, Appendicularia, Copepoda, Hydromedusae, Siphonophora, and fish eggs (Malej 1982). When prey touches a marginal tentacle of the jelly, nematocysts (stingers) are immediately discharged to paralyze prey and the marginal tentacle bends inward to the nearest oral arm (Rottini-Sandrini & Avian 1989). The oral arm is used to transport prey to the gastric cavity and to catch motionless prey (Rottini-Sandrini & Avian 1989). Because P. noctiluca eats small prey, it must spend much of its time foraging; these jellyfish are continuously in motion, at least during the day, suggesting that they are constantly hunting for food (Malej 1989).

Defense

P. noctiluca has several predators (Legovic 1987), the most well-studied of which is fish (Purcell & Arai 2001). A list of fish species which feed on P. noctiluca has not been published, but some of the fish species which feed on other members of the family Pelagiidae include Peprilus simillimus, Theragra chalcogramma, Zaprora silenus, and Pseudocaranx dentax (Purcell & Arai 2001). As a defense against predators, P. noctiluca tentacles have stinging nematocysts which inject toxins into any animals they contact (Quadrifoglio et al. 1986). However, predation pressures are probably much greater on the ephyra stage of P. noctiluca than the medusa stage (Malej 1989). Solitary individuals are rarely seen, and it has been suggested that aggregations of P. noctiluca provide protection from predation for both medusae and ephyrae (Malej 1989).

Recent Research


La Spada et al. (2002) isolated the nematocytes of P. noctiluca for the first time. They found that heat treatment, a technique used to isolate nematocytes in other scyphozoans, was not suitable for P. noctiluca because it damaged the cells. A chemical treatment using SCN- in solution was successful at isolating ~90 % of P. noctiluca nematocytes.

Mariottini et al. (2002) assessed the cytotoxicity of P. noctiluca venom on cultured cells. They found that the venom did not alter the DNA of the cells. Venom did induce high ATP production in cultured cells and 61% of cells were killed within 3 hours.

Graham et al. (2003) recently developed a new video technique for studying jellyfish. Prior to this time it was difficult to study large jellyfish in situ. Using their Jellycam, they found an intense layering of P. noctiluca at the halocline and pycnocline area. The jellies were found to be swimming upward, likely as part of a daily migration. Because medusae have the same salt content as the surrounding water, those coming from the bottom would have more salt in them and be denser than the water at the halocline. Accumulation of jellies at the halocline was likely due to reduced forward velocity caused by the greater density of the jellyfish.

Kariotoglou and Mastronicolis (2003) studied sphingophosphonolipids, structural elements of the cell-membrane of a number of marine species, in P. noctiluca and two molluscan species. They found that P. noctiluca has unique CAEP-IIM and CAEP-IIE (variations of ceramide 2-aminoethylphosphonic acid, a minor phosphonolipid) but that the composition of the major sphingophosphonolipids were very similar in P. noctiluca and mollusks.

Gasca and Haddock (2004) found an association between the parasitic amphipod Euthamneus rostratus and P. noctiluca.

Commercial Importance


There is no known commercial value of P. noctiluca. However, aggregations of jellies washing inshore are of concern because they can negatively impact tourism. P. noctiluca stings are painful and can cause pigmented lesions (Kokelj & Burnett 1990), Guillain-Barre syndrome (Pang & Schwartz 1993), and anaphylaxis, a severe allergic reaction (Togias et al. 1985). Although P. noctiluca has caused no known deaths, swimmers do not want to come into contact with this species. If stung, tentacles should be removed, and pouring vinegar on the sting may prevent further discharge of nematocysts (Burke 2002). An ice pack helps to dull the pain for most stings (Burke 2002). Gadolinium blocks the activation of nematocytes and may have practical implications for preventing stings (Salleo et al. 1994).

Bermuda Laws


There are currently no Bermuda laws regarding P. noctiluca (Wood & Jackson 2005). However, as this species has no commercial importance, it is not endangered by humans.

Personal Interest


I have always been fascinated by jellyfish because they are such beautiful and unique creatures. I first became interested in P. noctiluca when I recently found many of them washed ashore at Horseshoe Bay, Bermuda. There were hundreds of them laying onshore alongside the infamous Portuguese Man-of-wars (Physalia physalis). I was intrigued by their beautiful pink color and gelatinous consistency, so I decided to identify and research them.

References

Burke, WA. (2002) Cnidarians and human skin. Dermatologic Therapy. 15:18-25.

Fox, DL & Millott, N. (1954) The pigmentation of the jellyfish Pelagia noctiluca (Forskal) var. panopyra Peron & Lesueur. Proceedings of the Royal Society of London Series B. 142:392-408.

Gasca, R, & Haddock, SHD. (2004) Associations between gelatinous zooplankton and hyperiid amphipods (Crustacea: Peracarida) in the Gulf of California. Hydrobiologia. 530:529-535.

Goy, J, Morand, P, & Etienne, M. (1989) Long-term fluctuations of Pelagia noctiluca (Cnidaria, Scyphomedusa) in the Western Mediterranean Sea. Prediction by climatic variables. Deep Sea Research. 36 (2A):269-279.

Graham, WM, Martin, DL, & Martin, JC. (2003) In situ quantification and analysis of large jellyfish using a novel video profiler. Marine Ecology Progress Series. 254:129-140.

Heymans, C, & Moore, AR. (1924) Luminesence in Pelagia noctiluca. Journal of General Physiology. 6:273-280.

Kariotoglou, DM, & Mastronicolis, SK. (2003) Sphingophosphonolipid molecular species from edible mollusks and a jellyfish. Comparative Biochemistry and Physiology Part B. 136:27-44.

Kokelj, F, & Burnett, JW. (1990) Treatment of a pigmented lesion induced by a Pelagia noctiluca sting. Cutis. 46:62-64.

La Spada, G, Marino, A, & Sorrenti, G. (2002) Pelagia noctiluca “blooming” in the Strait of Messina: Preliminary studies on the applicability of two methods for isolating nematocytes. Marine Ecology. 23:220-227.

Larson, RJ, Mills, CE, & Harbison, GR. (1991) Western Atlantic midwater hydrozoan and scyphozoan medusae: in situ studies using manned submersibles. Hydrobiologia. 216:311-317.

Legovic, T. (1987) A recent increase in jellyfish populations: a predator-prey model and its implications. Ecological Modeling. 38:234-256.

Malej, A. (1982) Unusual occurrence of Pelagia noctiluca in the Adriatic Sea. Acta Adriatica. 23:97-102.

Malej, A. (1989) Behaviour and trophic ecology of the jellyfish Pelagia noctiluca (Forsskal, 1775). Journal of Experimental Marine Biology and Ecology. 126:259-270.

Malej, A, Faganeli, J, & Pezdic J. (1993) Stable isotope and biochemical fractionation in the marine pelagic food chain: the jellyfish Pelagia noctiluca and net zooplankton. Marine Biology. 116:565-570.

Mariottini, GL, Sottofattori, E, Mazzei, M, Robbiano, L, & Carli, A. (2002) Cytotoxicity of the venom of Pelagia noctiluca forskal (Cnidaria:Scyphozoa). Toxicon. 40:695-698

Moore, AR. (1926) Galvanic stimulation of luminescence in Pelagia noctiluca. Journal of General Physiology. 9:375-379.

Pang, KA, & Schwartz, MS. (1993) Guillain-Barre syndrome following jellyfish stings (Pelagia noctiluca). Journal of Neurology, Neurosurgery and Psychiatry. 56:1133.

Purcell, JE, & Arai, MN. (2001) Interactions of pelagic cnidarians and ctenophores with fish: a review. Hydrobiologia. 451:27-44.

Quadrifoglio, F, Avian, M, Del Negro, P, Princi, T, Scuka, M, Gavinelli, E, & Rottini Sandrini, L. (1986) Nematocysts and toxins of Pelagia noctiluca (Forskal). Nova Thalassia. 8:155-162.

Rottini-Sandrini, L, & Avian, M. (1983) Biological cycle of Pelagia noctiluca: morphological aspects of the development from planula to ephyra. Marine Biology. 74:169-174.

Rottini-Sandrini, L, & Avian, M. (1989) Feeding mechanism of Pelagia noctiluca (Scyphozoa: Semaeostomeae); laboratory and open sea observations. Marine Biology 102:49-55.

Rottini-Sandrini, L, & Avian, M. (1991) Reproduction of Pelagia noctiluca in the central and northern Adriatic Sea. Hydrobiologia. 216:197-202.

Salleo, A, La Spada, G, & Barbera, R. (1994) Gadolinium is a powerful blocker of the activation of nematocytes of Pelagia noctiluca. Journal of Experimental Biology. 187:201-206.

Sterrer, W, ed. (1986) Marine fauna and flora of Bermuda: A systematic guide to the identification of marine organisms. John Wiley & Sons, Inc., New York. pp. 742.

Togias, AG, Burnett, JW, Kagey-Sobotka, A, & Lichenstein, LM. (1985) Anaphylaxis after contact with a jellyfish. Journal of Allergy and Clinical Immunology. 75: 672-675.

Wood, JB, & Jackson, KJ. (2005) Bermuda. In: Caribbean Marine Biodiversity: the Known and the Unknown. Miloslavich, P, & Klein, E, eds. DEStech Publications, Inc., Lancaster, PA. pp 19-35.

Zavodnik, D. (1987) Spatial aggregations of the swarming jellyfish Pelagia noctiluca (Scyphozoa). Marine Biology. 94:265-269.

Links

Images of luminescent Pelagia noctiluca
Pelagia noctiluca
Know your jellyfish