Saturday, December 12, 2015

"Winter jelly-fishing" Lion's mane and Mushroom cap jelly collecting with videos

Mushroom cap jelly Rhopilema verrilli on exhibit




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Mushroom cap jelly on exhibit

We attempt to mimic the seasonality of the Chesapeake Bay species through our exhibits whenever possible. The assemblage of fish species varies greatly during the year, but so do many other groups of animals; each local jelly species is associated with a particular time of year, or more accurately, water temperature. The onset of cooler water temps in late Fall/early Winter - usually below 50 F - triggers the return of the "winter jellies" or Lion's mane jellies Cyanea capillata which we gladly display at the VLM. This is the largest jelly species in our area, and the most colorful. Their name describes the furry mane-like lower bell structure that can be vivid crimson, pink, and peach that makes them a striking species on display.

Lions mane 

Most of the year we house sea nettles, which are the most common and frankly disliked jelly in our area, due to their frequent contact with swimmers. Sea nettles thrive in warmer waters and are an attractive species, but nowhere near as interesting or impressive as large colorful lion's mane. So each Holiday season, we anticipate their appearance and look forward to some quality "jelly-fishing" ala' Sponge Bob and Patrick. We have an excellent spot at historic Yorktown, and this year have been fortunate to have nearly 70 degree weather. 

Scanning the water for jellies - someone has to do it.
One more for the exhibit

Along with the unseasonably warm weather this year (is there really "normal" weather?), there has been an unusually large number of mushroom cap jellies Rhopilema verrilli. We have never seen this species in significant numbers, but there have seen quite a few this year and several very large specimens nearly 20 inches across! Such large jellies are impractical to display and likely would not thrive on exhibit, but this year we took the opportunity to display some of the smaller mushroom caps we saw (approx 10 inch bells) along with the lion's manes. Their bells and lower bodies are much more rigid than lion's mane making their movement less fluid with a quicker pulse than the lion's manes. They also have lower mouth/arms that look like clusters with gastric pouches beneath in lieu of elaborate, flowing tentacles. So far both have fed well and make for an interesting contrast in shape, movement and structure. 

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