Not to put a damper on your summer’s day, but i just read the following in the July/August 2008 EcoNews newsletter. It’s a downer, no doubt, but i like Victoria’s Guy Dauncey , who publishes the newsletter, because of his irrepressible optimism. In fact, he’ll be getting a good chunk of my $100 climate change rebate from the BC government.
I highly recommend EcoNews as a monthly read — subscribe using the box on the left of the page. And put pressure on our nice Canadian governments, who are dragging their feet in every way possible even as the citizenry forges ahead with grassroots initiatives.
Something extremely disturbing is happening in the world’s oceans. Thanks to our seemingly endless hunger for seafood, we have killed off 90% of the large predatory fish.
There is a consequence to this, since large predatory fish eat other fish — it’s like removing 90% the police from a community. The result in this case is an explosion of jellyfish, since we have killed 90% the sharks, swordfish, tuna, cod, and leatherback turtles that love to eat them.
Holiday destinations in the Mediterranean and Adriatic seas are being plagued with them, in some places as thick as 100 jellyfish per cubic meter of water.
In the US, they are everywhere from Cape Cod to Hawaii.
In May, a mass of jellyfish forced a Japanese nuclear reactor to close down after they blocked its seawater cooling system.
In Northern Ireland, an invasion of non-native mauve stinger jellyfish in a dense pack 10 miles square by 35 feet deep killed 120,000 salmon in a hatchery overnight.
In Namibia, south-west Africa, once one of the most prolific fishing areas in the world, then plundered by the fishing fleets, the jellyfish have moved in and taken over.
Very few fish eat jellyfish, but jellyfish love to eat young larval fish and eggs, making recovery extremely difficult.
“We’re pushing the oceans back to the dawn of evolution, a half-billion years ago when the oceans were ruled by jellyfish and bacteria,” said Jeremy Jackson, a marine ecologist at the Scripps Institution of Oceanography who has dubbed what’s happening as “the rise of slime”.
In addition to us removing their predators, jellyfish thrive in warmer waters — and US and Australian climate researchers reported in June that the world’s oceans have warmed 50% faster over the last 40 years than previously thought, due to climate change.
The only good news is that in the 4% of the oceans that have remained free of human impact, the sharks and predatory fish still dominate, keeping order in the marine world.
The solution is for at least 1/3rd of the world’s oceans to be declared global marine protected areas, with no fishing of any kind allowed. We know from experience in New Zealand and elsewhere that this allows the fish to recover — but time is running out, and global leadership is painfully slow.