Sightings of comb jellies will be studied

In the autumn, offshore storms wash unexpected life up onto our local beaches. Last week, large numbers of translucent blobs washed up on Short Sands Beach in York, Maine. Small drops of iridescent jelly on the sand.

There is something compelling about animals such as these that are so far removed in form from what we typically think of as animals. These are among the most primitive of animals — drifting with the whims of ocean currents. Based on the size (a little over 1 inch in length) and plump little gooseberry shape, these were probably sea gooseberries (Pleurobrachia pileus). Sea gooseberries belong to a group of animals called ctenophores. While they are often mistaken for jellyfish, they lack stinging cells — they are in a totally different group.

Their common name, "comb jelly," refers to the eight rows of fused cilia (known as comb rows) that run the length of their egg-shaped bodies; iridescent rows like the teeth of a comb that beat in synchrony, propelling these little gelatinous blobs through the water.

Comb jellies are true minimalists. They sense their prey with the most rudimentary of senses — something called an ectodermal nerve net, the most primitive of nervous systems, a dispersed network of sensory cells instead of a central brain. It isn't clear how they follow their prey, however electrical activity in the neural net increases when prey are present and are sensing something. They hunt with long sticky tentacles that capture prey (smaller plankton-like fish larvae, tiny shrimp, copepods) and haul it into their mouths.

We call it a mouth but I don't know whether this adequately describes it — the comb jelly mouth takes in food but it also spits out waste. Comb jellies don't need the kind of digestive system we have, nor the reproductive system — in addition to waste, sperm and eggs are released from the mouth. Comb jellies are at one with the water — nutrients and oxygen simply diffuse in and out of their cells. Fertilization occurs externally, after spitting them out, sperm and eggs intermingle in the open ocean.

Sightings of comb jellies and jellyfish have been increasing in the Gulf of Maine over the past couple years. It is currently not known whether this is unusual, whether warming oceans are causing jellies to increase in number as their predators dwindle or whether this is normal — we simply do not have historic data on jellyfish distribution in the Gulf of Maine.

So, the Gulf of Maine Research Institute has partnered with the Bigelow Laboratory for Ocean Science to build a library of jellyfish sightings (both true jellyfish and comb jellies). They are asking any visitors to the Gulf of Maine who happen to see comb jellies or jellyfish to do the following: Take a photo, record any helpful information (a description, the date, time and location) and either tweet the sighting with the hashtag #mainejellies, email to jellyfish@bigelow.org, or post to www.facebook.com/gulfofmaine with hashtag #mainejellies.

Susan Pike, a researcher and an environmental sciences and biology teacher at St. Thomas Aquinas High School, welcomes your ideas for future column topics. She may be reached at spike3116@gmail.com. Read more of her Nature News columns online.