The South Carolina Department of Natural Resources published guides to many threatened animals living in the state.  This guide gives information about the Cannonball Jellyfish, including description, status, habitat, conservation challenges & recommendations, and measures of success

Griffin, DuBose B.

Murphy, Thomas M.

South Carolina State Documents Depository

Cannonball Jellyfish 
Stomolophus meleagris  
Contributors:  DuBose B. Griffin and Thomas M. Murphy (SCDNR) 
 
DESCRIPTION  
 
Taxonomy and Basic Description 
 
Cannonball, or cabbagehead, jellyfish (Stomolophus 
meleagris; L. Agassiz 1860), also known as jellyballs, 
belong to the class Scyphozoa and order Rhizostomeae. 
Agassiz (1860) described and illustrated the medusa of 
cannonballs using specimens collected from Wassaw 
Island, Georgia and Charleston, South Carolina. The 
hemisperical bell reaches 20 to 25 cm (8 to 10 inches) in size and is bordered with brown 
pigment. It has short, protruding oral arms with secondary mouth folds (scapulets) at the base of 
the bell covered with mucus for trapping small prey.  Stomolophus meleagris means “many 
mouthed hunter.” The mucus is also thought to be a response to disturbance rather than for 
feeding (Phillips et al. 1969; Larson 1976).  
 
Status 
 
The cannonball jellyfish is not a state or federally listed species; however, cannonballs are 
ecologically important because they are the major prey base for the endangered leatherback sea 
turtle (Dermochelys coriacea) and warrant conservation.   
 
POPULATION DISTRIBUTION AND SIZE 
 
Cannonball jellyfish have been reported from New England to Brazil in the western Atlantic 
(Kramp 1961; Larson 1976), from southern California to Ecuador in the eastern Pacific and from 
the Sea of Japan to the South China Sea in the western Pacific (Kramp 1961; Omori 1978).  They 
are one of the most abundant scyphomedusae along the southeastern and Gulf coasts of the 
United States (Mayer 1910; Kraeuter and Setzler 1975; Burke 1976; Calder and Hester 1978). 
Their success is based in part on their ability to grow rapidly and take advantage of ephemeral 
secondary production (Larson 1986). 
 
Current distributions of most populations are undocumented.  However, numerous reports of 
their occurrence in the southeast exist.  Mayer (1910) reported them as abundant during the 
winter and spring off the coast from Florida to South Carolina.  Brooks (1882) and Gutsell 
(1928) reported them in North Carolina as very abundant in June and July and common 
throughout the summer in the sounds and ocean. In South Carolina and Georgia, they are 
reported as the most common scyphomedusae occurring sporadically year round (Kraeuter and 
Setzler 1975; Calder and Hester 1978). 
 
The seasonal cycle of cannonball jellyfish is described by Rountree (1983) as the following: 
 
Cannonball jellyfish 
SCDNR 
“Small populations of large adults appear offshore in the spring and move inshore by 
early summer. The origin of these populations of adults has not been determined, but it 
seems likely that they are survivors from the previous season (Kraeuter and Setzler 
1975). It is also possible that they are early spawned medusae from more southern 
waters which are carried north by prevailing spring ocean currents…Kraeuter and 
Setzler (1975) found the young medusae move out from estuarine waters into more 
saline waters as they grow. Two concurrent events are therefore hypothesized: 1) first 
generation populations move from offshore in the spring to inshore waters in the 
summer and finally into brackish waters in the fall; 2) second generation populations 
move out from estuarine waters beginning in the mid-summer and continuing through 
the fall.” 
 
The South Carolina Department of Natural Resources (SCDNR) has been conducting surveys in 
the South Atlantic Bight since 1986 through a program called the Southeast Area Monitoring and 
Assessment Program – South Atlantic Shallow Water Trawl Survey (SEAMAP-SA). Tows were 
conducted each year in spring (April to May), summer (July to August) and fall (October to 
November) in shallow coastal waters from Cape Hatteras, North Carolina to Cape Canaveral, 
Florida. From 1989 to 2000, only the presence or absence of cannonball jellyfish was recorded 
on each individual tow. During this time, cannonballs were present in 43 percent of the tows 
during all three survey seasons.  Beginning in 2001, total numbers of cannonballs were counted 
and recorded for each tow (102 tows per season; J. Boylan and P. Webster, SCDNR, pers. 
comm.). These data are presented in the following bar graph. Since 2001, there has been an 
apparent steady decline in the relative abundance of cannonballs with very low catch rates 
observed in 2004.  The reason(s) for this decline are unknown; however, anomalously low 
summer water temperatures in the coastal waters in summer 2003 may be related.   
 
 
 
 
 
 
 
 
 
 
 
 
 
Tow counts of cannonball jellyfish from 2001 – 2004.  
Year
2001 2002 2003 2004
To
ta
l N
um
be
r o
f I
nd
iv
id
ua
ls
0
20000
40000
60000
80000
M
ea
n 
W
ei
gh
t o
f I
nd
iv
id
ua
l (
kg
)
0.0
0.2
0.4
0.6
0.8
1.0
Total for Year
Spring
Summer
Fall
Mean Weight
In another study, density and distribution of leatherback sea turtles were associated with 
abundance and distribution of cannonball jellyfish. Mean numbers of leatherbacks observed for 
each sampling event in each year was related to the density of cannonball jellyfish observed from 
2001 through 2003. However in 2004, cannonballs were in unprecedented low numbers and 
leatherbacks were still observed. These data are presented in the graph below.  Numbers of 
cannonballs observed from 2001 though 2003 provided a relative index for leatherback 
abundance (S.R. Murphy unpub. data). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
HABITAT AND NATURAL COMMUNITY REQUIREMENTS  
 
Cannonball jellyfish are found in estuarine and saline waters.  Temperature and salinity 
measured during the SCDNR SEAMAP-SA tows (unpub. data) indicate they are found in waters 
with an average temperature of 23.1°C (74°F) and in salinities from 17.7 to 36.5 parts per 
thousand (ppt) with an average of 33.8 ppt. Cannonballs feed on zooplankton, primarily bivalve 
veligers, a mollusk larval stage (Larson 1991). They have also been shown to prey on all stages 
of red drum larvae (Duffy et al. 1997).  However, they do not sting humans (Calder and Prodgen 
1977). Cannonballs are strong horizontal and directional swimmers (Shanks and Graham 1987). 
They are known for their symbiotic relationships with other marine species, specifically 10 
species of fishes as well as juvenile longnosed spider crabs (Libinia dubia). These symbionts 
feed on both the zooplankton taken in by the jellyfish and on the host’s medusae.  Symbionts 
may also use the bell for protection (Corrington 1927; Gutsell 1928; Phillips et al. 1969; 
Rountree 1983). 
 
Annual shifts in abundance of leatherback and cannonball 
jellyfish observations, 2001 – 2004. 
198
339
132
2
124
690
120
347
0
100
200
300
400
500
600
700
800
2001 2002 2003 2004
Year
N
um
be
r
Mean number of cannonball jellyfish per tow
Mean number of leatherbacks per flight x 10
CHALLENGES 
 
Since cannonball jellyfish are dependent on the abundance of zooplankton in nearshore waters, 
any activity, marine or terrestrial, that could affect water quality, should be considered a 
detrimental to this species. Such problems include harmful algal blooms, oil spills and nonpoint 
source pollution. Also, cannonball jellyfish’s dependence on bivalve veligers suggests a 
relationship with the health of bivalves.  
 
The potential exists for cannonball jellyfish to be adversely affected by commercial fishing.  
Currently, South Carolina does not regulate a commercial cannonball jellyfish fishery.  However, 
this fishery does exist in other portions of the cannonball’s range.  Japan imports 5,400 to 10,000 
tons of jellyfish products valued at 25.5 million dollars annually (Omori and Nakano 2001).  
Currently, Asian countries are developing fisheries management plans to conserve jellyfish 
because populations are unstable or declining due to pollution, overfishing or climate change.  
Consequently, dealers are looking for new sources of jellyfish (Hsieh et al. 2001). Interest in 
cannonball jellyfish from the United States increased recently because of high consumer demand 
in Asia (Hsieh et al. 2001). A fishery in Florida has processed cannonball jellyfish since 1992 
(Rudloe, 1992) and a commercial trawl fishery for cannonball jellyfish in Georgia exists (M. 
Dodd, GADNR pers. comm.). Rising demand in Japan and Southeast Asia may create an 
international market for cannonball jellyfish from South Carolina coastal waters. Any 
development of commercial fisheries for cannonballs must consider its affect on this species’ 
role in the food web of coastal ecosystems, as well as the affects on endangered leatherback sea 
turtle through incidental mortality in trawls and reduction of their food resources. Life cycles of 
cannonball jellyfish involve federal and state waters; therefore, cannonballs should be managed 
on a regional scale (S.R. Murphy unpub. data). 
 
CONSERVATION ACCOMPLISHMENTS 
 
In 1989, SCDNR began surveying cannonball jellyfish during SEAMAP-SA tows.  These 
surveys have provided an index of relative abundance of cannonball jellyfish in coastal waters 
along the southeastern United States, which has led to a better understanding of this species. In 
addition, current regulations requiring the use of turtle excluder devices (TEDs) in shrimp 
trawling nets has also provided protection to cannonball jellyfish.  Although required to reduce 
incidental catch of turtles, TEDs also excludes cannonballs greater than 10 cm (4 inches), thus 
increasing survival. TEDs have been required for shrimp trawls since 1990. 
 
CONSERVATION RECOMMENDATIONS  
 
• Determine the distribution of cannonball jellyfish in state waters and how this species 
affects the distribution of leatherback sea turtles. 
• Examine basic life history and determine source of the spring recruitment of cannonball 
jellyfish. 
• Determine effect of temperature, salinity and rainfall on spring reproduction. 
• Determine southeastern population structure through genetic analysis of cannonballs. 
• Continue to monitor population trends through SCDNR SEAMAP-SA sampling of 
cannonballs. 
• Determine the maximum sustainable yield for a harvest fishery.  
• More fully examine the species role in predator-prey dynamics.  
• Encourage municipalities to adopt Best Management Practices (BMPs) that protect water 
quality and bivalve health by reducing nonpoint source runoff from highways, 
agricultural fields and housing developments. 
• Monitor effectiveness of existing BMPs such as setbacks, retention ponds, and vegetated 
buffers for preventing nutrient and contaminant runoff into coastal waters. 
• Examine relationship between bivalve populations and cannonball reproduction. 
• If a fishery develops in South Carolina for cannonball jellyfish, it should be monitored 
and regulated to avoid overexploitation and appropriate harvest techniques should be 
identified that are protective of other marine species. 
• Facilitate the development of a regional management plan for cannonballs.    
• Develop an education program that stresses the importance of cannonball jellyfish to 
coastal ecosystems and that they are harmless to humans. 
 
MEASURES OF SUCCESS 
 
Determining the distribution, life history, habitat needs and southeastern population structure and 
trends would represent a measure of success for this species.  Methods that protect water quality 
are also likely to protect cannonball jellyfish and associated predator/prey relationships.  In the 
event that more protective BMPs are implemented, SEAMAP data can be used to indicate 
whether these measures have affected cannonball jellyfish populations.  Producing a regional 
management plan for this species would greatly benefit the cannonball jellyfish throughout the 
southeastern coastal area.   
 
LITERATURE CITED 
 
Agassiz, L. 1860. Contributions to the natural history of the United States of America. Vol 3. 
Little Brown and Co., Boston. 301 pp. 
  
Brooks, W.K. 1882. List of medusae found at Beaufort, N.C., during the summers of 1880 and 
1881. Stud. Biol. Lab. Johns Hopkins Univ. 2:135-146. 
 
Burke, W.D. 1976. Biology and distribution of the macrocoelenterates of Mississippi Sound and 
adjacent waters. Gulf Resource Report 5:17-28. 
 
Calder, D.R. and B.S. Hester. 1978. Phylum Cnidaria. In:  An annotated checklist of the biota of 
the coastal zone of South Carolina. R.G. Zingmark (ed). University of South Carolina 
Press:87-93. 
 
Calder, D.R. and Prodgen. 1977. Guide to common jellyfishes of South Carolina. South Carolina 
Sea Grant Marine Advisory Bulletin 11. 
 
Corrington, J.D. 1927. Commensal association of a spider crab and a medusa. Biology Bulletin. 
53:346-350. 
 
Duffy, J.T., C.E. Epifanio and L.A. Fuiman. 1997. Mortality rates imposed by three scyphozoans 
on red drum (Sciaenops ocellatus Linnaeus) larvae in field enclosures. Journal of 
Experimental Marine Biology and Ecology 212:123-131. 
 
Gutsell, J.S. 1928. The spider crab, Libinia dubia, and the jellyfish, Stomolophus meleagris, 
found associated at Beaufort, North Carolina. Ecology 9(3):358-359. 
 
Hsieh, Y-H.P., F.M. Leong, and J. Rudloe. 2001. Jellyfish as food. Hydrobiologia 451:11-17. 
 
Kraeuter, J.N. and E.M. Setzler. 1975. The seasonal cycle of scyphozoa and cubozoa in Georgia 
estuaries. Bulletin of Marine Science 25(1):66-74. 
 
Kramp, P.L. 1961. Synopsis of the medusae of the world. Journal of the Marine Biological 
Association U.K. 40:7-469. 
 
Larson, R.J. 1976. Marine flora and fauna of the northeastern United States. Cnidaria: 
Scyphozoa. NOAA Tech Report NMFS Cir. 397:18p. 
 
Larson, R.J. 1986. Feeding and growth of the sea nettle Chrysaora quinquecirrha (DeSor) in the 
laboratory. Estuaries 9:376-379. 
 
Larson, R.J. 1991. Diet, prey selection and daily ration of Stomolophus meleagris, a filter-
feeding Scyphomedusae from the NE Gulf of Mexico. 
 
Mayer, A.G. 1910. Medusae of the world, Hydromedusae and Scyphomedusae. Carnegie 
Institute Washington, Publication 109(3):735p. 
 
 
Omori, M. 1978. Zooplankton fisheries of the world: a review. Marine Biology 48(3):199-205. 
 
Omori, M. and Nakano, E. 2001. Jellyfish fisheries in southeast Asia. Hydrobiologia 451:19-26. 
 
 
Phillips, P.J., W.D. Burke and E.J. Koener. 1969. Observations of the trophic significance of 
jellyfishes in Mississippi Sound with quantitative data on the associative behavior of 
small fishes with medusae. Transcripts of the American Fisheries Society 98(4):703-712. 
 
Rountree, R.A. 1983. The ecology of Stomolophus meleagris, the cannon ball jellyfish, and its 
symbionts, with special emphasis on behavior. Undergraduate Thesis-UNCW. 69p. 
 
Rudloe, J. 1992. Jellyfish: a new fishery for the Florida panhandle. A report to the U.S. 
Department of Commerce Economic Development Administration. EDA Project no. 04-
06-03801, pp. 35. 
 
Shanks, A.L. and W.M. Graham. 1987. Oriented swimming in the jellyfish Stomolophus 
meleagris L. Agassiz (Scyphozoan: Rhizostomida). Journal of Experimental Biology and 
Ecology 108:159-169. 


Cannonball Jellyfish

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Cannonball Jellyfish

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