Increases in jellyfish numbers around the world may be yet another coal mine canary in relation to our impact on the planet.
Scientists from the University of Columbia have found increasing jellyfish populations in 62 per cent of the regions they analyzed; including East Asia, the Black Sea, the Mediterranean, the Northeast U.S. Shelf, Hawaii, and Antarctica.
According to PhD student Lucas Brotz, lead author of the study, analysis of available information from 1950 to today for more than 138 different jellyfish populations has confirmed what was previously only anecdotal evidence.
Places where rising numbers of jellyfish were noted were often areas heavily impacted by humans – through pollution, overfishing and warming waters.
Back in the early 1990’s I was studying a specific species here in Australia – catostylus mosaicus; the mosaic jellyfish. Not much was known about them at the time. My interests weren’t so much environmental, but more commercial as it is a species eaten in Asian nations.
I was convinced the incredibly high numbers of jellyfish was in part due to oyster farming activities in the river as jellyfish feed on oyster spat; so again, the increase was human-related.
Unfortunately my biomass studies and related research were never accepted by those I needed on-side as I didn’t have one those uni degree thingies. As far as I know, that jellyfish resource (one that causes its fair share of problems) remains untapped. It’s a shame as harvesting and processing some of those jellyfish would have been a very environmentally friendly enterprise.
Anyway, probably the more important point from the University of British Columbia’s study – performed by folks with a degree (me bitter? never!) – is the one about warming waters being a possible factor.
As ocean temperatures rise due to global warming, we can expect to see not only increased numbers of jellyfish, but species also turning up in places where they didn’t previously.
This is a big deal.
While increased numbers of jellyfish could be great for some aquatic life, such as turtles; it may negatively impact on other species.
Masses of jellyfish can impact on human activities too – sometimes with quite serious consequences aside from stings. For example, in the space of 3 weeks during 2011, jellyfish forced the shutdown of three nuclear power stations in Japan, Scotland and Israel when the critters began blocking water intake filters.
Also, jellyfish moving into places where they haven’t frequented before may have major knock-on and unpredictable effects on local ecosystems.
More jellyfish is just a single example of the thousands, perhaps millions of changes that are going on right now as our world warms and reacts to all the other damage we do. How it will all pan out is anyone’s guess – we’re really at the mercy of the butterfly effect now.