Six combs a-sparkling

Ctenophore photo from Tumblr

Comb jellies sparkle! Light refracted by 8 moving rows of comb-like plates inside their transparent
bodies create this sparkling phenomenon as they move through the water. One of the most studied
comb jellies is the sea walnut or Leidy’s comb jelly, Mnemiopsis leidyi, a native of Eastern United States
and South American (Massachusetts to Argentina) waters [i] which was accidentally introduced in the
Eastern Atlantic (likely via ballast waters) [ii]. The sea walnut can be a voracious predator on zooplankton
including other ctenophores as well as fish and invertebrate larvae [iii]. Thus, an increase in the abundance
of a local sea walnut population may cause a depletion of the local fish [iv] and invertebrate larval [v]
populations. If it wasn’t for this rather adverse effect on commercially important fish species, this tiny
sparkle of the oceans would have probably remained anonymous, most likely becoming fodder to other
organisms and becoming a natural part of an alien ecosystem.

To learn more about comb jellies or if you have other information you want to add about them, visit SeaLifeBase or become a collaborator and email us at sealifebase@fin.ph.

Inspired by: 12 Planktons of Christmas by Michele Collet

[i] Faasse, M.A. and K.M. Bayha, 2006, The ctenophore Mnemiopsis leidyi A. Agassiz 1865 in coastal waters of the Netherlands: an unrecognized invasion?, Aquatic Invasions 1(4):270-277. 

[ii] Bartley, D.M. (comp./ed.), 2006. Introduced species in fisheries and aquaculture: information for responsible use and control (CD-ROM). Rome, FAO.

[iii] McNamara, M.E., Lonsdale, D.J., Cerrato, R.M., 2010. Shifting abundance of the ctenophore Mnemiopsis leidyi and the implications for larval bivalve mortality. Marine Biology 157:401-412. 

[iv] Oguz, T., Fach, B., Salihoglu, B., 2008. Invasion dynamics of the alien ctenophore Mnemiopsis leidyi and its impact on anchovy collapse in the Black Sea. Journal of Plankton Research 30(12): 1385-1397. 

[v] Shiganova, T.A. and Y.V. Bulgakova, 2000. Effect of gelatinous plankton on the Black and Azov Sea fish and their food resources. ICES Journal of Marine Science 57:641-648.

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