Jellyfish Populations Are Increasing
Posted on 5 December 2019
While warming seas and habitat destruction are causing a mass loss of several species, there’s one animal that’s thriving: the jellyfish.
Jellyfish populations have shot up over the past 20 years due to a combination of factors. Firstly, because they have no complex body parts, they can adapt pretty easily to changing conditions in the ocean. Things like temperature, acidity and salinity (the level of salt in the ocean) have changed dramatically over the years, which many species haven’t been able to keep up with – except jellyfish.
Secondly, overfishing has removed many of the creatures that once kept jellyfish under control. This gives jellyfish plenty of room to multiply. Next, shipping and underwater drilling actually help jellyfish because they give them hard surfaces to reproduce on.
And lastly, when huge amounts of fertiliser run-off enter the ocean, it causes plankton and algae populations to increase massively. They then suck the oxygen out of the water, causing a “dead zone” where most marine life cannot survive. But some jellyfish can exist in these zones, feeding off the plankton without any competition.