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American comb jelly, Mnemiopsis leidyi


Short description of Mnemiopsis leidyi, American comb jelly

A comb jelly up to 180 mm in length, usually transparent or slightly milky and translucent with four rows of small ciliated combs which are iridescent by day and may glow green by night.  A key distinguishing feature is the presence of oral lobes which span nearly the entire length of the body.

Description of Mnemiopsis leidyi, American comb jelly status in GB

The sea walnut was recorded in the Ouse Esturay in 2016 and has been recorded from the North Sea off the Netherlands coast since 2006.

Habitat summary: Mnemiopsis leidyi, American comb jelly

It occurs in the water column of shallow estuaries, bays and coastal waters, tolerating temperatures of 0-32 °C and salinities from <two – 38 psu. 

Overview table

Environment: Marine
Species status: Non-Native
Native range: Northeastern U.S.A.
Functional type: Predator
Status in England: Non-Native
Status in Scotland: Non-Native
Status in Wales: Non-Native
Location of first record: The Wash, Norfolk
Date of first record: 2014

Distribution map

Map of the UK with areas shaded to show the UK distribution of American comb jelly

GB Distribution from NBN Atlas

Author's name:

Natalie Sweet

Last updated:

October 3rd 2019

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