Aequorea victoria (Murbach and Shearer, 1902)

Common name(s): Many-ribbed hydromedusa, Water jellyfish

Synonyms:Aequorea aquorea, Aequorea flava, Aequorea forskalea
Phylum Cnidaria
    Order Leptomedusae
      Family Aequoreidae 
Aequorea victoria, 4 cm diameter, captured in central Rosario Strait July 12, 2007.  The broad, open manubrium with frilly lips can be seen through the bell.  The tentacles are retracted.
(Photo by: Dave Cowles, July 2007)
Description:  A saucer-shaped hydromedusa with a well-developed velum.  Has 80 or more narrow, unbranched radial canals (sometimes only 60) which extend all the way to the margin of the bell.  The slender gonads run along most of the length of the radial canals and do not hang down.  Gonads are bluish in males, rosy in females.  Has one to several unbranched tentacles for each radial canal. All tentacles extend from the margin of the bell.  The tentacles are in a single row around the margin of the bell, can be extended long or held very short (as in the photo above), and are usually not all of the same size.  The manubrium is short and wide, with ruffled edges ("lips") but can be closed all the way when prey is inside.  Usually colorless.  Diameter up to about 8 cm.

How to Distinguish from Similar Species:  Aequorea spp range from Alaska to Baja California, and get much larger than this species (to 25 cm) off Alaska.

Geographical Range:  British Columbia to central California.  Closely related species can be found in other parts of the Pacific, on the U.S. Atlantic coast from Maine to Texas, and in the Mediterranean Sea.

Depth Range:

Habitat:  Pelagic, often nearshore.

Biology/Natural History:  This is the largest of our local Hydrozoan jellyfish, though the Scyphozoan jellyfish can grow much larger.  Feeds mainly on gelatinous plankton such as Mitrocomella polydiademata and other hydromedusae, on ctenophores, on polychaetes, and on appendicularians.  It may occasionally be cannibalistic.  Also eat larval fish such as Pacific herring, Clupea pallasi.  This species is bioluminescent and may flash brightly when disturbed.  A related species off Baja California can divide by fission.  The hydroid stage of this polyp is not often seen in the field.  Some references suggest that the polyps may be what is now identified as Campanulina forskali.

Aequorea victoria is the source for "green fluorescent protein", which is a marker used in molecular biology.



Dichotomous Keys:
  Flora and Fairbanks, 1966
  Kozloff 1987, 1996
  Smith and Carlton, 1975 (as Aequoria sp)

General References:
  Harbo, 1999
  Kozloff, 1993
  McConnaughey and McConnaughey, 1985 (as Aequorea aequorea)
  Niesen, 1994
  Niesen, 1997
  O'Clair and O'Clair, 1998
  Sept, 1999
  Wrobel and Mills, 1998

Scientific Articles:

Amsterdam A, Lin S, Hopkins N., 1995.  The Aequorea victoria green fluorescent protein can be used as a reporter in live zebrafish embryos.  Developmental Biology 171:1  123-129

Costello, John H., Sean P. Colin, and John O. Dabiri, 2008.  Medusan morphospace:  phylogenetic constraints, biomechanical solutions, and ecological consequences.  Invertebrate Biology 127(3): 265-290

Nancy E. Freitag,* and Kathleen E. Jacobs, 1999.  Examination of Listeria monocytogenes Intracellular Gene Expression by Using the Green Fluorescent Protein of Aequorea victoria.  Infection and Immunity 67:4 1844-1852

Mats Ormö,    Andrew B. Cubitt,    Karen Kallio,    Larry A. Gross,    Roger Y. Tsien,   S. James Remington, 1996.  Crystal Structure of the Aequorea victoria Green Fluorescent Protein.  Science 273: 1392-1395

Douglas C. Prasher, Virginia K. Eckenrode, William W. Ward, Frank G. Prendergast and Milton J. Cormier, 1992.  Primary structure of the Aequorea victoria green-fluorescent protein.  Gene 111: 229-233

Purcell, JE; Siferd, TD; Marliave, JB, 1987.   Vulnerability of larval herring (Clupea harengus pallasi ) to capture by the jellyfish Aequorea victoria .  Marine Biology 94:2 157-162

Reum, Jonathan P., Mary E. Hunsicker, and Caroline E. Paulsen, 2010.  Species composition and relative abundance of large medusae in Puget Sound, Washington.  Northwest Science 84:1 pp. 131-140

Christoph Reichel, Jaideep Mathur, Peter Eckesdagger , Kerstin Langenkemper, Csaba Koncz, Jeff Schell, Bernd Reiss, and Christoph MaasDagger, 1996.  Enhanced green fluorescence by the expression of an Aequorea victoria green fluorescent protein mutant in mono- and dicotyledonous plant cells.  Proceedings of the National Academy of Sciences 93: 5888-5893

Vroemen S.F.; De Jonge H.; Van Marrewijk W.J.A.; Van der Horst D.J.; Cao C.; A. Ashton-Miller J.; Schultz A.B.; Alexander N.B.; Monger B.C.1; Chinniah-Chandy S.; Meir E.; Billings S.; Greene C.H.; Wiebe P.H., 1998.   Sound scattering by the gelatinous zooplankters Aequorea victoria and Pleurobrachia bachei.  Deep-Sea Research Pert II: Topical Studies in Oceanography 45:7 1255-1271

Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors:

This species is less common around Rosario in late spring and early summer but becomes quite common by the end of summer.
June 30, 2009:  Many Aequorea victoria are washing up on the beach at Rosario Bay.  Most of them are moribund, and have this flatworm crawling over them.  The flatworm is up to 5 mm long.

Authors and Editors of Page:
Dave Cowles (2006):  Created original page
Jonathan Cowles (2007):  Updated page with CSS