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Maine Jellyfish Tracking


Reports of jellyfish sightings in the Gulf of Maine seem to have increased over the past few summers. GMRI, the Bigelow Lab for Ocean Sciences, and the Island Institute are partnering to gather information from the public on where and when jellyfish appear in Maine waters.

We lack good historic data on jellyfish distribution in the region. As a result, experts can only speculate about why they are here and whether these occurrences are unprecedented. To better understand these jellyfish, scientists in the Gulf of Maine need your help to track the species we are seeing.

One of our partners, Dr. Nick Record, at the Bigelow Laboratory for Ocean Sciences has been building a library of jellyfish sightings. As more sightings are reported, he hopes to develop predictive models that tell us when to expect jellyfish blooms.


Public data contributions will be an essential component to this scientific work. We want to make it easier to report and collect information on sightings to share with the research community and each other. 

If you encounter jellyfish along the Maine coast this summer, please take a photo and report your findings in one of the following ways:

Along with your photo, please include as much information about the sighting as possible, including:

  • Date
  • Time
  • Location
  • Description (size, approximate abundance, type if known) 

Gulf of Maine Jellyfish Guide

Common Northern Comb Jelly
(Bolinopsis infundibulum)

Moon Jelly
(Aurelia aurita)
Lion's Mane Jellyfish
(Cyanea capillata)

Size: up to 6 inches in length

Can emit of bioluminescent glow at night if disturbed.

Danger: Comb jellies do not have tentacles and unlike jellyfish, do not sting.

Reference: Bolinopsis infundibulum Müller, 1776." Encyclopedia of Life, available from Accessed 13 July 2015

Size: 2-6 inches in diameter

Recognizeable by the distinct four moons in the center of the bell. These are the  reproductive organs. They usually travel in groups.

Danger: Tentacles and arms are used to catch food. They are poisonous to small marine creatures, but harmless to humans.

Reference: Jacinto, V., Bos, A. and E. Ershova, eds. "Aurelia aurita." Encyclopedia of Life, available from Accessed 13 July 2015.

Size: With tentacles, can be several meters long.

Danger: Tentacles have toxin that will give a painful sting if touched.

Reference: Ershova, E. eds. "Cyanea capillata." Encyclopedia of Life, available from Accessed 13 July 2015.