Jellies may be change indicator species and reports around the world are telling us about growing numbers of seajelly 'smacks' or' swarms' or 'blooms'.
|A common Australian jelly, Catostylus mosaicus, or blue blubber jelly (Photo courtesy of Tony Isaacson)|
Probably the most spectacular example are the devastating blooms of the massive jellies, 'Nomuras', off the coast of Japan. As adults they weigh in at 220kg and measure 2m in diameter. They have been swarming in the Japan Sea since 2002, clogging fishnets and overturning trawlers owing to their size. (see BBC article here).
Why is this happening? Some scientists remind us that we have been taking too many fish from the sea that eat jellies. Others point out that changes occurring from human activities like; marine pollution from stormwater, ocean acidification and temperature rise to name a few, may just be giving jellies the edge they need to reclaim the ocean where they were once the top predator hundreds of millions of years ago.