The European Commission is taking the UK to court for failing to protect endangered harbour porpoises.
Britain is supposed to have created special sites round the coastlines to protect the animals, but has proposed only two.
The Commission says it has repeatedly urged the government to fulfil its obligations as other nations have done.
The government has not yet made a comment on the court action.
The move comes as the Wildlife Trusts launch a campaign for the UK to declare many more Marine Conservation Zones (MCZs) to safeguard mammals round the shores.
They say safeguards to the UK’s domestic marine life should be as strong as they are around Britain’s overseas territories.
Ministers recently promised to safeguard an area of ocean equivalent to 16 times the land area of the UK.
But that figure refers mainly to the seas round far-flung islands. Progress on our own marine reserves is slower.
The government said it would announce new sites in Phase Three of its marine conservation zones (MCZs).
But this will not happen until 2018.
That would add to the 50 existing zones dotted round the UK, but a spokesman would not say how many new MCZs were being considered.
Wildlife campaigners say the existing areas need to be joined together to ensure safe passage for mobile species like dolphins.
Lissa Batey, from the Wildlife Trusts, told BBC News: “We can’t achieve an ecologically coherent network of protected areas without including top predators in the process – whales, dolphins, porpoises and basking sharks – which are still under threat.
“Many are suffering from the impacts of fishing, whether direct or indirect, increased boat traffic, marine developments and the more persistent effects of pollution.
“By designating areas of the sea, we can provide safe havens and some impacts can be limited or removed altogether.”
The vast majority of the UK’s protected space, though, surrounds oceanic islands forming part of the legacy of empire.
Ministers are safeguarding the waters around four islands in the Pacific and Atlantic, including one of the world’s biggest zones around Pitcairn, home to descendants of the Bounty mutineers.
There will be two more zones around the south Atlantic islands of Ascension and Tristan da Cunha.
The British moves contribute to an extraordinary period for ocean conservation. President Obama has also announced the world’s biggest protected zone round Hawaii.
Dr Mark Spalding, from the US group The Nature Conservancy hailed recent global developments.
He told BBC News: “The UK’s dramatic expansion of protected areas is a tremendous contribution to the conservation of the oceans, and one that needs to be roundly applauded.
“The numbers are eye-watering, but actually we should really look beyond these numbers. In both Pitcairn and St Helena these protected areas have been established with, and for, the local communities.
“That means sustainable fishing and the potential for growth in ecotourism. It’s a different model from simply closing off large tracts of the ocean – and while that’s important too, it’s not a model that can work everywhere. We should watch these places and learn from them.”
Professor Callum Roberts, from the University of York, told BBC News the vast majority of MCZs are what he called worthless paper parks.
“They have no management, virtually nothing in the way of protection, and fail almost every test of a worthwhile marine protected area,” he said.
The Wildlife Trusts agreed enforcement should be improved but said that already in Lyme Bay, one of the early protected zones, species were returning.
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Article source: http://www.bbc.co.uk/news/science-environment-37497203