Dalhousie scientist asks beachgoers to record jellyfish sightings

Jellyfish swim in a tank at the Inbursa Aquarium in Mexico City, Friday, May 30, 2014. Mexican magnate Carlos Slim inaugurated the underground aquarium, one of the biggest in Latin America. (AP Photo/Rebecca Blackwell)

HALIFAX -- They are a maligned menace of the sea -- slimy blobs that float silently through the water before delivering a nasty sting to swimmers.

Jellyfish make their way to waters off the East Coast every summer, becoming a pest to people but an important food source for some turtles that travel from their breeding grounds in the Caribbean to feast exclusively on the gelatinous creatures.

Now a researcher studying the endangered leatherback sea turtle wants to know where the jellyfish go and how numerous they may be, and she's calling on citizen scientists to help out.

Bethany Nordstrom, a graduate biology student at Dalhousie University in Halifax, is asking people to record their sightings of the jellyfish this summer to gain insight into the turtles' feeding habits and the predator-prey relationship between the species.

"We know there are people who are out on the water all the time that see jellyfish year after year," she said Wednesday. "So I'm looking for anyone who spots a jellyfish or even if it's washed up on the beach to report it to me, just to get a better idea of when these jellyfish are showing up and how long they persist and in what areas."

Nordstrom said scientists know quite a bit about the turtles, which are classified as endangered in Canadian waters, but very little about the lowly jellyfish. Understanding where the jellyfish go will add to knowledge about the location of the turtles' critical habitats and the abundance of their food.

She said it could also provide insight into changes in the marine ecology, since they are collecting information on environmental conditions like water temperature. The unique research will serve as a baseline for future years and provide the scientific community with an understanding of broader changes in the ecosystem.

"It's really important to have this baseline data just so you can keep track of species like this," she said. "They have a lot of impact not only on leatherback sea turtles, but also on lots of human activities."

In particular, the turtles like to feed on the lion's mane, a jellyfish with a purplish hue and very long red tentacles that can cause painful stings. They also eat clear moon jellyfish that have four small rings on top and comb jellies.

Nordstrom, who is collaborating with the Bigelow Laboratory for Ocean Science in Maine, said people can email her at jellyfishΓåòdal.ca with the location, jellyfish description and date of the sighting.

She said she's already received reports of sightings, suggesting the jellyfish are showing up a bit early this year. Nordstrom will also do field work in July when she goes out with Fisheries officers to conduct groundfish surveys as well as trips in August off Cape Breton.

She said she appreciates the creatures may not be a favourite animal for study, but hopes that people will share their encounters with them.

"They do deliver a bit of a sting so they can ruin a nice summer day," she said with a laugh. "Anything that kind of wraps around you in the water is not pleasant!"