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Jumping into a lake with millions of jellyfish may sound worse than swimming with sharks and, for the most part it is, unless you happen to be snorkeling in Jellyfish Lake - located in the Eli Malk island of The Republic of Palau, in the Pacific Ocean, 500 miles from the Philippines.
The marine lake is one of about 70 lakes that are scattered all over the rocky island nation and is accessible only by crossing over a narrow ridge that separates it from the surrounding lagoon. Once there, visitors are in for a real visual treat - the lake is filled with millions of Golden Jellyfish floating around like lava lamps.
Scientists believe that this particular species became entrapped in the lake millions of years ago, when a submerged reef rose from the sea and created a landlocked salt water area.
Over the years, the jellyfish have evolved to adjust to their small universe. One of the biggest changes is lack of predators that the fish need to defend themselves against. Accordingly, the fish has lost their ability to sting as aggressively, making it safe for humans to snorkel with them.
The Golden Jellyfish have also adopted to their micro-environment in other ways - In the oceans, jellyfish have a propensity to migrate and while the fish haven't forgotten the ways of their ancestors, their area of migration is quite small - spanning about one km round-trip.
Accordingly, every sunny morning, they head out across the lake until they get to the farthest sunny spot usually by mid-day. They then turn back, completing their entire migration, before the end of the day.
The Golden Jellyfish avoid shaded areas for two reasons - One because their only predator in the lake, the anemone are waiting on the sides, with their tentacles outstretched to snare these beautiful creatures, and two because similar to other jellyfish, they too derive their color and a lot of their energy from the algae that live inside their tissues. The algae need sun to produce sugars, which they share with the jellyfish, who in turn not only keeps them safe from predators, but also, provide a 'mobile' home with almost constant sun.
The lake is also home to the Moon Jellyfish species, which remain in deeper waters and are therefore difficult to spot, as well as, a number of other beautiful species of sponges, anemones, sea squirts and mussels - but it is the Golden Jellyfish that tourists flock to swim with! To read more about these beautiful jellyfish go to www.fishnfins.com.
sources:fishfins.com, dailymail.com.uk, pbs.org