Saturday, January 10, 2015

Lion's Mane Jellies video Cyanea capillata

The VLM displays a variety of jelly species: moon jellies, sea nettles and lion's mane. Fortunately for us, we are surrounded by the Chesapeake Bay and its tributaries. Several species of jellies are native here and tend to follow salinity and temperature conditions that best suit them. because of the large seasonal fluctuations and the different preferences of different jelly species, each season is dominated by one main species. Winter in the bay is prime time for lion's mane jellies. When the water temperature dips below 50 degrees F - usually by mid-December - they appear seemingly out of nowhere.
video
A large lion's mane jelly in our exhibit

Lion's mane jellies have many long hair-like tentacles

Ice coats the jetty below the Coleman Bridge, Yorktown, VA

But actually their ephyrae, or juvenile form had already arrived and has been feeding and growing, morphing into the full blown medusa or adult jelly stage that most people recognize. The adult species of lion's mane jellies that frequent our area rarely get larger than a foot or so across and several feet long (still a big jelly), but in other parts of the world, lion's mane jellies can grow a bell over 6 feet across with tentacles stretching over 100 feet - the largest jelly species in the world! 


This lion's mane jelly on exhibit has a 5 inch bell and tentacles ~ 16 inches long

Each winter we anticipate arrival of the lion's manes and carefully monitor water temperatures in the nearby York River. We also have a network of members, staff, and volunteers of the VLM that report when they begin to see them. Perhaps the only jelly collector most people have ever heard of is SpongeBob SquarePants, but our staff is also out there with specialized "jelly" nets ready to collect wild jellies to augment our live collection throughout the year. Because of their size and beautiful colors, lion's mane are particularly desirable for exhibition. Unfortunately, January can be pretty cold on the water and this week was especially brutal. With air temps in the teens and wind chill near zero, it had better be worth it - and it was. We caught enough wild jellies to switch our exhibit from primarily sea nettles to lion's manes and will continue to display them and collect them throughout the winter.

 Sea nettles are more recognizable because they are here in the summer and are known for stinging swimmers. They even have a NOAA website dedicated to predicting their presence inshore.

Moon jellies do have tentacles, though they are much shorter than either nettles or lion's mane

Ctenophores or comb jellies are harmless and often luminesce at night

Like most jellies, lion's manes use their stinging tentacles to ensnare and subdue prey. In this area, they feed on virtually anything that becomes entangled in their tentacles as they flow behind the travelling jelly; it could be anything from zooplankton to small fishes. Here at the VLM we hand feed them daily a mix of Artemia nauplii and diced seafood such as shrimp, squid, or scallops. They will be on display throughout the winter and spring, when we will start gearing up for sea nettle season.






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