In the pristine waters of the northern Gulf of Mexico lies a sleeping giant of sorts. The Pink Meanie Jellyfish (Drymonema larsoni) is an elusive and rare species of jellyfish that was only described to science in 2010. These bright pink jellies can reach a bell diameter of 3 feet and sport hundreds of tentacles that trail a considerable distance behind them. So how does a giant, fluorescent jellyfish go unknown for so long?
The secret lies in their fascinating life cycle and unique biology. Adult Pink Meanies feed exclusively on other species of jellyfish, primarily Moon Jellies. In fact, they seem to have no stomachs for storing their food. Instead, they trap moon jellies in their billowing mouth arms and slowly digest them, absorbing their nutrients over several hours. Metal!
So what does this have to do with anything? Well, Pink Meanies seem to only show up in large numbers every decade or so. It's common for a few to be spotted each year towards the end of summer, and they are often mistaken for Lion's Mane Jellyfish. There are likely many factors at play for what makes it a "Pink Meanie year". Moon jellyfish almost definitely play a role in this, however. No Moon Jellies means no food, and no Pink Meanies.
2022 just so happened to be a very good year for Drymonema. In late September I began to hear about sightings of multiple Pink Meanies in the Pensacola Beach area. These sightings increased to the point of many jellies being spotted in one area. Opportunities don't happen like this often, so I quickly made plans to drive down to Pensacola from Charlotte.
It is always a little nerve wracking planning a very spontaneous trip and then driving many hours (in this case 9 hrs each way) hoping you will find a rare and elusive jellyfish. There have been plenty of trips that ended empty handed. Fortunately though, the rumors were absolutely true. The first morning of my trip I found over ten Pink Meanies of varying size. Some of them were at least 3' in diameter. Including their mouth-arms, they rivaled me in size!
My goal here was to obtain viable embryos or larvae so I could bring them back to our lab and study them in captivity. Growing them in captivity would mean the convenience of being able to study them at any time. Additionally, cultures could be shared with other institutions around the world. So I began sampling gonadal tissue from each jelly I cam across. Despite the weather being 90 degrees, I wore a full wetsuit to limit the amount of times I got stung. Despite this, I could still feel hundreds of tentacles wrap around my legs and ankles as I approached the jellyfish. And stung I did get! Their name would suggest otherwise, but I found the stings to be fairly mild. They did leave a red rash that itched for a few days afterwards. As I gently turned over each Pink Meanie to gather samples, it was common to see multiple half digested moon jellies slough out of their arms. Truly an eldrich horror.
My AirBnB was converted into a laboratory that evening so that I could observe the samples I took and hopefully generate embryos using in vitro fertilization.
Fertile eggs were found, as were 2 and four cell embryos. This is where my luck ran out and things get pretty weird, though. I carefully packed up over a dozen containers of samples and made the trek back to Charlotte. Upon returning, it seemed like many of the eggs had deteriorated. Low success rates are pretty common with in vitro so this wasn't super abnormal. Planula larvae were observed swimming around these containers which would normally be a huge cause for celebration. I was initially skeptical though. These planula settled and developed into polyps which are nearly identical in appearance to moon jellyfish polyps. Bamboozled by the Moon jellies yet again!
So what now? There is always a chance that the polyp stage of Drymonema bears a remarkable resemblance to Aurelia. My hopes are not super high, but time will tell. Once the polyps mature and start producing ephyra, I will have a better idea of their true identity.
Despite that roadblock, this trip was incredibly fulfilling. I had never seen a Pink Meanie in person before then. There is something so humbling and magical about swimming up to a massive Pink Meanie, as it calmly drifts through the gulf waters. It is a memory I will not forget, and I greatly look forward to a second chance at culturing them. But for now, these giants will likely go back to rest so they may wake again in years to come.
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