Lion's Mane Jellyfish Photos

The lion's mane jellyfish ranges from the Arctic to Mexico. The largest of all jellyfish species, in Arctic waters its bell can reach 8 feet with tentacles trailing up to 100 feet long. Juveniles are pink, turning red as they mature into reddish brown or purple adults. The largest documented specimen found in Puget Sound was found beached on Whidbey Island ( in 1998 ) and measured 5 feet across the bell. 

Like all jellyfish, the lion's mane rides the ocean currents, pulsing its bell to force water out of the bell and push itself in the opposite direction to the current.  Its life cycle goes through five stages, including two distinct body shapes (medusa and polyp).  During the benthic, or bottom-dwelling stage, they attach to a surface — wood or stone are favorites — feeding with tiny tentacles and cloning new jellies.  A single colony of jellyfish can be traced back to a polyp that may have first cloned itself hundreds of years before. Any piling in Puget Sound clothed with what looks like small white polyps may be in fact paved with the polyps of jellies.

In April, bottom-dwelling jelly polyps bud off tiny, baby jellyfish. By July, the juveniles have grown to the adult gobs we know so well. Adult males then release sperm into the water, where it is gathered by females that brood the eggs internally, then release them as ciliated beings no bigger than the head of a pin. These drift to the bottom, where they attach, and begin the life cycle anew.

Most adults die by October, victims of bacterial infection, depleted plankton supplies and the appetites of fish and other predators. Lions Mane Jellyfish typically feed on tiny crustaceans, zooplankton, small fish and moon jellies.

The venom in the nematocysts of the Lion’s Mane is a powerful neurotoxin.  If a human were to get stung enough, it could be fatal, provided sufficient poison had been absorbed by the body. The venom can cause paralysis of the breathing muscles, effectively suffocating the victim.  More common for divers is welt-like stings across the top of the upper lip (one of the few areas we have exposed). These small stings can be equated to a bee sting (applying vinegar with a q-tip will provide immediate relief).   The stinging cells ( nematocysts ) in the tentacles can actually live for months after they are detached from the Jellyfish ( often chopped up by a boat propeller or current ).  These are culprits that most often sting divers, who didn’t even see the small floating tentacle.  Do try to avoid doing the full face plant into a live Lion’s Mane, which could be very painful.

Note:  This article was also published in Northwest Dive News Magazine, in the October,  2003 issue.

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