What's that blob!?! The Pacific ocean hosts a variety of gelatinous species, and depending on the tide, they end up along Oregon's shore lines. This summer, our beach was inundated with one species in particular: the water jelly. So many washed up that some locals began to refer to 2016 as "The Summer of the Water Jelly."
Water jellies are found along the entirety of the West Coast, from Alaska to California. Like all jellyfish, they're scientifically categorized as a plankton. Water jellies can't move against the ocean's currents, and are thus at the mercy of local ocean conditions.
As they drift, the jellies unfurl their 100 plus poisoned-laced tentacles. Have no fear, though, the water jelly's tentacles aren't harmful to humans! They are, however, laced with nematocysts. Nematocysts are specialized cells that contain a barbed, sometimes venomous structure, shaped like a coiled thread. Nematocysts occur in animals scientifically grouped as coelenterates; anemones are another celenterate, which also uses nematocysts.
Although the water jelly's nematocysts are too weak to affect humans, it effectively employs them for both self-defense and to capture prey. A majority of the water jelly's diet is comprised to zooplankton, such as copepods and other larvae plankton. Its appetite is so voracious that the density of water jellies in any particular aquatic area has a direct inverse correlation to the zooplankton density of that area. In other words, the more water jellies, the less plankton.
The water jelly is hunted and consumed by other larger jellyfish, such as the Brown Sea Nettle and the Lion's Mane Jelly. There are even document cases of water jelly cannibalism. It's hard to blame the jelly, though, because with no heart, blood, or brain, it just might not know any better!
The lifecycle of water jellies is quite fascinating. Early in the spring, tiny jellies begin to form and then bud away from their hydroid colonies. These tiny jellies grow rapidly until they reach about 3 cm in diameter, at which point their growth rate slows and energy redirects to gamete production. These tiny jellies have separate sexes, and will "free-spawn" either their eggs or sperm into the ocean daily. The eggs are thus fertilized, floating in the water, where they they develop into swimming planulae larvae. These larvae eventually settle down on hard surfaces, and grow into new hydroid colonies. This process repeats annually.
A couple of cool facts about water jellies:
- Water jellies are capable of producing bioluminesce. The light they produce is a faint bluish which, to us, may appear more green.
- Sometimes, animals called hyperiid amphipods actually live within water jellies; check the shoreline and see if you can spot one!
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| Photo Courtesy of Tiffany Boothe, Seaside Aquarium |
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| Photo Courtesy of Tiffany Boothe, Seaside Aquarium |
