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Potentially Misidentified Species:
In the IRL region, potential exists for confusion with the moon jelly
Aurelia aurita based on size similarity, but the two species are markedly
different in appearance otherwise. In other parts of the world,
Phyllorhiza co-occurs with other mastigiid jellyfish which are similar in
appearance, including several species belonging to the genus Mastigias.
II. HABITAT AND DISTRIBUTION
Regional Occurrence:
P. punctata is a coastal and estuarine jellyfish whose wide
native distribution includes Australia and much of the
Indo-Pacific including the Philippine archipelago (Heeger et al.
1992).
Regionally, populations of P. punctata have persisted within a
few isolated Caribbean lagoon systems (e.g., Puerto Rico) for at
least four decades. More recently, established populations have
been reported in Brazil (Haddad and Nogueira 2006). For the last
several years, an established population has existed in the Gulf of Mexico which may become
extraordinarily dense under favorable environmental conditions (Graham et al. 2003).
IRL Distribution:
Spotted jellyfish were first collected from the IRL and identified
in June, 2001. St. Johns River Water Management District
scientists encountered two specimens in the IRL proper near the Melbourne causeway in Brevard County. One of these was collected
and transported to Harbor Branch Oceanographic, Fort Pierce, where
it was positively identified as P. punctata. In light of the
explosive population of this species in the Gulf of Mexico the
previous year, the occurence of P. punctata prompted boat and/or aerial surveys of
the central IRL between Vero Beach and State Road 520 in Cocoa to
estimate the size of the population. Approximately 10-12
individuals were spotted by the aerial survey. Survey leader W.M.
Graham of Dauphin Island Sea Lab, Alabama, estimated the actual
population at that time to be approximately ten times that number,
based on extensive survey experience gained while following the
Gulf of Mexico population explosion (W.M. Graham, personal
communication).
III. LIFE HISTORY AND POPULATION BIOLOGY
Age, Size, Lifespan:
Phyllorhiza punctata is a large jellyfish whose average adult bell width is
approximately 35 cm (Perry and Larsen 2004). Very large
individuals nearly twice that diameter have also been reported from
Gulf of Mexico specimens (Graham et al. 2003).
Abundance:
An explosive summer P. punctata bloom, followed by a
winter/spring decline or disappearance has occurred in Brazil
every year since a population became established around 2001.
The reasons for these fluctuations are unknown (Haddad
and Nogueira 2006). A similar exponential population explosion
occurred in 2000 in the Gulf of Mexico, although subsequent
seasonal blooms have not been as large.
Reproduction:
Scyphozoans have a life cycle that can be broadly divided into two
parts: a free-living medusa (the "jellyfish stage") and an
attached, sessile polyp stage. Sexes are separate in the medusae
and these produce haploid gametes that combine through external
fertilization to form free-swimming planula larvae. Planulae
search out suitable settlement sites and leave the water column to
assume a sessile benthic existence. Thse scyphistomae then give
rise to new offspring in the form of free-swimming medusae.
Immature medusae, called ephyrae, detach from the ends of the
sessile scyphistomae in a process termed strobilation. Ephyrae
develop into mature medusae over a period of usually several weeks
(Rupert et al. 2004).
Embryology:
In a Western Australia P. punctata population study, Rippingale and
Kelly (1995) noted the presence of small (< 2 cm diameter) medusae
and ephyrae in early summer. In Brazil, the
presence of all size classes of P. punctata in late winter and
spring suggested a prior period of continuous ephyrae release
synchronized to seasonal high water temperatures and extended
photoperiod (Haddad and Nogueira 2006).
IV. PHYSICAL TOLERANCES
Temperature:
Although not rigorously examined, a link between abnormally warm
weather and P. punctata regional population explosions has been
suggested (Haddad and Nogueira 2006).
Salinity:
Though some degree of euryhaline tolerance is expected in an
estuarine inhabitant, there is some evidence that low salinities
negatively impact the ability of P. punctata to thrive.
Rippingdale and Kelly (1995) report the absence of the species from
Western Australia estuary study sites during low salinity periods
following heavy rains, and also its return when higher salinity
conditions returned in the summer months. Graham et al. (2001),
suggest that the lack of photosynthetic zoanthellae in Gulf of
Mexco Phyllorhiza specimens (see below) might be the result of
hyposalinity stress.
V. COMMUNITY ECOLOGY
Trophic Mode:
Like most members of Phylum Cnidaria, the tentacles of Phillorhiza
are equipped with stinging cells called cnidocytes. Within these
cells are stinging organelles called nematocysts. When discharged,
nematocysts can immobilize small prey items that are subsequently
ingested. Nematocysts are also used as a defense mechanism.
The planktonic egg and larval stages of several fish species (including commercially important species such as red snapper in the gulf of Mexico) are probably
important as prey items.
Additionally, throughout its native range and much of its
introduced range, P. punctata also harbor endosymbiotic
zooxanthellae within their bell. In a relationship analogous to
that of reef-building tropical corals and their resident
zooxanthellae, primary production of the photosynthetic
zooxanthellae likely fulfills a large proportion of the nutritional
needs of the host jellyfish (Garcia and Durbin 2003).
The invasive Gulf of Mexico P. punctata populations were/are
unusual in that they lacked endosymbiotic zooxanthellae (Graham et
al. 2003). Zooplanktivory was/is the sole trophic mode of these
populations which, nonetheless, attained high population numbers.
Associated Species:
None described.
VI. INVASION INFORMATION
Invasion History:
P. punctata was recorded only from Indo-Pacific waters prior to the
1950s. In 1955, an Atlantic basin population was discovered in
Brazil (Haddad and Nogueira 2006). A large population there
persisted briefly in coastal waters off the southern half of the
country but disappeared within a few years. At the time, the
organism was identified as Mastigias scintillae, another mastigiid
jellyfish similar in appearance to Phyllorhiza (Moreira 1961, in
Haddad and Nogueira 2006). Three decades later, around 1991, a
second established population of P. punctata was reported from
Brazil, this time off of the northeastern coastline (Silveira and
Cornelius 2000). Ten years later (2001), evidence pointed to a new
southern population of this non-indigenous jellyfish (Fuller 2005,
Haddad and Nogueira 2006). This population may be the result of a
natural range extension of the established northern population, or alternatively,
accidental transport by the shipping industry, or perhaps an irruptive
event within an extant cryptic population. Regardless of the
mechanism, Haddad and Nogueira (2006) believe that P. punctata is
now widespread in Brazil, occurring in both northern and
southern waters. Since 2001, the established P. punctata population in Brazil undergoes a
large summer bloom, and then declines and disappears the subsequent
winter and spring (Haddad and Nogueira 2006).
An established population of spotted jellyfish in a mangrove lagoon
in Bonqueron Bay, Puerto Rico was reported by Cutress (1973). The
first report of the animal in U.S. waters dates to California in
1981 (Carlton and Geller 1993). These Phillorhiza invasions pale
in magnitude to one recorded in the northern Gulf of Mexico off
Louisiana, Alabama and Mississippi in the summer of 2000. At that
time, an estimated 10 million P. punctata medusae invaded the
region and persisted at very high numbers between June and September
before rapidly declining (graham et al. 2003). Interestingly,
despite the magnitude of the population explosion, northern Gulf of
Mexico P. punctata entirely lacked symbiotic zooxanthellae.
In 2001, P. punctata was identified from collected specimens
occurring in Florida in the central Indian River Lagoon near the
city of Melbourne. Aerial and boat-based surveys undertaken at
that time revealed only a handful of individuals. Even fewer
individuals were detected the following year, and no irruptive
events have been detected subsequent to this.
Natural ocean circulation patterns may have been sufficient to
transport P. punctata up into the northern Gulf of Mexico from
established Caribbean Sea populations, as has occurred in other
species (Graham 1998). Circulation set up by the Loop Current
(part of teh Gulf Stream; a warm ocean current in the Gulf of
Mexico that flows northward between Cuba and the Yucatan peninsula)
and eddies spun off from it may have effected such transport (Johnson
et al. 2004).
The precise mechanisms of invasion in each of the above cases
remain a matter of speculation. Invasions into new locales may
occur via attachment of the sessile polyp stages to ship hulls or
other submerged and towed structures. Larson and Arneson (1990)
have proposed hull-fouling as the likely dispersal method
transporting spotted jellyfish between the Pacific Ocean and the
Caribbean Atlantic. Transport of free-swimming stages in ballast
water has probably also led to some of the invasions (Carlton and
Geller 1993). Passage of vessels through the Panama Canal probably
facilitated introduction from the Pacific into the Atlantic basin
(e.g., Graham et al. 2003, Bolton and Graham 2004).
The fact that the first documented occurrence of the species in
Brazil dates back to 1955 suggests that P. punctata was first
transported between ocean basins at least 50 years ago (Silveira
and Cornelius 2000)
Putative transport routes and vectors may be critically examined
through comparative molecular or morphological analyses among
various populations. In fact, a recent comparative molecular study
by Bolton and Graham (2004) concluded that the Brazillian
population examined was not Phyllorhiza, but rather a member of
genus Mastigias.
Potential to Compete With Natives:
Non-native jellyfish species like P. punctata have the
capacity to compete with native species for food resources. To
what extent such competition occurs is unknown, as are its
ecological ramifications. P. punctata may also compete with
other taxa for food resources (see below).
Possible Economic Consequences of Invasion:
Direct negative economic impact of the 2000 Gulf of Mexico P.
punctata population explosion included several million dollars of
fishery losses, primarily due to net damage. Some evidence also
points to a greater than 25% reduction in the northern Gulf of
Mexico white shrimp (Penaeus setiferus) harvest at that time,
attributable to competition between the shrimp and jellyfish for
food resources. (Graham et al. 2003). Predation on pelagic fish
eggs and bivalve larvae was also pronounced (Graham et al. 2003).
VII.
REFERENCES
Bolton T.F. and W.M. Graham. 2004. Morphological variation among populations of
an invasive jellyfish. Marine Ecology Progress Series 278:125-139.
Carlton J.T. and J.B. Geller. 1993. Ecological roulette: the global transport
of nonindigenous marine organisms. Science 261:78-82.
Cutress C.E. 1973. Phyllorhiza punctata in the Tropical Atlantic.
Associations of Island Marine Laboratories of the Caribbean, Cumana 9:14.
Fuller P. 2005. Phyllorhiza punctata. Nonindigenous Aquatic Species
Database, Gainesville, FL. Available online.
Garcia J.R. and B. Durbin. 1993. Zooplanktivorous predation by large
scyphomedusae Phyllorhiza punctata (Cnidaria: Scyphozoa) in Laguna
Joyuda. Journal of Experimental Marine Biology and Ecology 173:71-93.
Graham W.M. 1998. First report of Carybdea alata var. grandis (Reynaud
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1998:28-30.
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Limnology and Oceanography, Summer Meeting, Abstract.
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Argonauta argo. Marine Ecology Progress Series 88:293-296.
Johnson D.R., Perry H.M., and W.M. Graham. 2004. Using nowcast model currents to explore
transport of non-indigenous jellyfish into the Gulf of Mexico. Marine Ecology
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Larson R.J. and A.C. Arneson. 1990. Two medusae new to the coast of
California: Carybdea marsupialis (Linnaeus, 1758), a cubomedusa and
Phyllorhiza punctata von Ledenfeld, 1884, a rhizostome scyphomedusa. Bulletin
of the Southern California Academy of Sciences 89:130-136.
Moreira M.G.B.S. 1961. Sobre Mastigias scintillae sp. nov. (Scyphomedusae,
Rhizostomeae) das costas do Brasil. Boletim do Instituto Oceanografico da
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Omori M. and M. Kitamura. 2004. Taxonomic review of three Japanese species of
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Perry H. and K. Larsen. 2004. Picture Guide to Shelf Invertebrates of the
Northern Gulf of Mexico. NOAA/NMFS online publication.
Ray G.L. 2005. Invasive Marine and Estuarine Animals of the Gulf of Mexico.
Aquatic Nuisance Species research Program. Document ERDC/TN ANSRP-05-4.
Rippingale R.J. and S.J. Kelly. 1995. Reproduction and survival of
Phyllorhiza punctata (Cnidaria: Rhizostomeae) in a seasonally fluctuating
salinity regime in western Australia. Marine and Freshwater Research
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Rupert E.E., Fox R.S., and R.D. Barnes. 2004. Invertebrate Zoology. Seventh
Edition.
Silveira F.L. and P.F.S. Cornelius. 2000. New observations on medusae
(Cnidaria, Scyphozoa, Rhizostomae) from the northeast and south Brazil, Acta
Biologica Leopoldensia 22:9-18.
Report by:
J. Masterson, Smithsonian Marine Station
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