Fast-breeding jellyfish could take over our seas if we don’t act now to protect threatened marine ecosystems, Northern Ireland wildlife experts have warned.

The ‘rise of slime’ is coming unless we halt the threatened collapse of marine ecosystems, the Ulster Wildlife Trust said.

Seafloor habitats are being destroyed by overfishing, rising water temperatures and dwindling marine biodiversity, reducing the ability of the seas around Ireland to recover and support humans long-term, the Trust said.

And this could pave the way for increasing invasions of jellyfish and microbes — the forerunner of which was the devastating attack by billions of mauve stingers on a major salmon fishery on the Antrim coast in 2007.

The Northern Salmon Company lost millions of pounds when the jellyfish descended on organic salmon being reared in Glenarm Bay and Red Bay, destroying the entire stock. Mauve stingers invaded the Irish Sea from the Antrim Coast to Dumfries and Galloway and as far north as the Shetland Islands.

Meanwhile, the jellyfish have become so prevalent off the Mediterranean coastline that they are being scooped up and used as land fertiliser, Melanie Gomes from the Trust said.

And in other parts of the world the animals are sweeping in as ecosystems collapse, she warned.

“The predictions for these animals is that they are increasing due to factors such as overfishing and predator loss, nutrient enrichment, coastal development, and climate change.”

Jellyfish compete for many of the same food sources as fish — so fewer fish in the seas means more room for jellyfish.

Northern Ireland is by no means isolated from these threats, yet we are not doing enough to put in place adequate control measures, Ms Gomes said.

“We urgently need an effective network of Marine Protected Areas with a core of highly protected marine reserves to fully protect our marine biodiversity and fishery nursery sites. Marine reserves — where no damaging activities are allowed — are key to the recovery of biodiversity and the resilience of marine ecosystems.

“The Marine Bill for Northern Ireland is also vital to ensuring we have healthy and productive seas for all sea users although more work needs to be done.”