Too early for lion’s mane jellies?

Posted 3/16/23

It couldn’t be an orange, yet suspended below the surface was a round reddish object.

At first I thought what I had only seen briefly on last Monday’s morning row to Cole Farm and back …

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Too early for lion’s mane jellies?


It couldn’t be an orange, yet suspended below the surface was a round reddish object.

At first I thought what I had only seen briefly on last Monday’s morning row to Cole Farm and back was a partially submerged coke can or some other form of trash. But then about 50 yards farther was another orange blob below the surface. Now I was on the watch and there were more of them. Could they be jellyfish?

I have seen dish-sized reddish jellyfish in May and early June, but never at this time of year. Usually they’re much closer to the surface, pink or orange and less clearly defined with tentacles sweeping at their sides.

This seems too early for lion’s mane jellyfish. They had to be something else.

So, I did what has become the common thing to do when you’re on the hunt for information – appeal to Google.

I was surprised by what I found when I did a search on lion’s mane jellyfish.

Wikipedia reported the  “The lion's mane jellyfish (Cyanea capillata), also known as the giant jellyfish, arctic red jellyfish, or the hair jelly,  is one of the largest known species of jellyfish. Its range is confined to cold, boreal waters of the Arctic, northern Atlantic, and northern Pacific Oceans. It is common in the English Channel, Irish Sea, North Sea, and in western Scandinavian waters south to Kattegat and Øresund. It may also drift into the southwestern part of the Baltic Sea (where it cannot breed due to the low salinity). Similar jellyfish – which may be the same species – are known to inhabit seas near Australia and New Zealand.”

From additional sites I gleaned the jellyfish can be as big as seven feet in diameter. That was a sobering revelation. Can you imagine such creatures washing up along the 39 miles of Warwick shoreline?

Additional searches found an article in ecoRI News written by Rhode Island resident and author Todd McLeish.  He wrote that changes in the jellyfish-like creatures could have implications for the health of the bay’s fish populations.

His inquiries led him to an article in the Journal of Plankton Research and a report that while the number of jellyfish hasn’t increased higher bay temperatures have led them to be more prevalent earlier in the spring and later in the fall than previously observed.

“And because they feed voraciously on copepods — zooplankton near the bottom of the food chain, upon which many young fish feed — they are likely limiting the amount of food available to larval fish. Ctenophores also eat fish eggs and some larval fish, which also could impact fish populations” McLeish writes.

I had no idea where this deep dive into jellyfish would take me.

McLeish quotes Emily Slesinger, a doctoral student at Rutgers: “They’re dormant and slow and lazy in winter, but once conditions get favorable and the ecosystem begins ramping up with phytoplankton blooms and copepods increasing, that’s when ctenophore abundance increases and they’re rapidly feeding. That’s when they start to reproduce.”

McLeish gained additional insights from Barbara Sullivan-Watts, emerita marine research scientist at URI’s Graduate School of Oceanography: “Sullivan-Watts said that it could be because of the 50 percent reduction in nutrients being discharged into the bay from wastewater treatment plants since 2005. That may have affected the abundance of phytoplankton, limiting food available to zooplankton like copepods, and ultimately decreasing the availability of food to ctenophores. The scientists have detected a slight decrease in the abundance of ctenophores in the bay in the last few years, which may be the result of this cascade of events.”

“While that cascade hasn’t yet been proven, what is known is that some species of copepods that used to be abundant in Narragansett Bay are now less common because so many are eaten by ctenophores.”

I have heard this line of reasoning from shell fishermen for the decline of quohogs in what were once productive harvesting areas in the bay. Indeed, the bay is much cleaner to the naked eye. I can see the bottom at six feet on most days when a good day 15 years ago was two to three feet.

On my most recent outing the bottom was clearly visible at six feet. I kept an eye out for red blobs, but there weren’t any. All I spotted were flecks of white shells and dark clumps of seaweed waving in the tidal swing.

Might have I seen a premature bloom of jellyfish like some of the anxious crocus and daffodils in my yard? The Bay frequently offers an adventure and, if you’re curious, a lesson. 

jellies, side up


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