Every walk on Morro Strand State Beach is an adventure. On December 24 while strolling along looking at birds I noticed some most unusual organisms at my feet. Dozens of crystalline-like cylinders covered with warty bumps were strewn around the high tide line. I couldn’t wait to get home and call my docent marine biologist guru to get an ID. Faylla Chapman immediately told me they were pyrosomes, a free-floating tunicate that are typically found in the upper layers of open ocean in warm seas. What were they doing here in Morro Bay?
Wikipedia to the rescue for possible answers! In 2017 pyrosomes were found in masses along Pacific beaches as far north as Alaska. Scientists are not sure why, but one hypothesis is that unusually warm water over several years may have been the cause.
Pyrosomes are cone-shaped colonies made up of hundreds to thousands of zooids, each a few millimeters in size, embedded in a gelatinous tunic that joins all the individuals. The cylinders can range up to 60’ long. Each of the bumps you see in the close-up photo is a single zooid capable of filtering microscopic plant cells to feed itself.
The movement of the colony is at the mercy of currents, tides and waves which brought them to our local beaches. There were more on Christmas Day when I walked to Morro Rock but the numbers diminished the next day. Keep your eyes open when you ‘re on the beach for these so-called “sea pickles.”