The common fisheries policy needs urgent reform
The UK's seas are to be given much better protection, the government says.
It says this will benefit more than 44,000 different species which live in British waters.
In two years' time it plans to produce a comprehensive assessment of the state of the UK's seas.
But several campaign groups have criticised the plans, which they believe are too slow a response to a serious crisis.
The plans were disclosed by the Environment Secretary, Margaret Beckett, at the launch of the UK's first marine stewardship report.
Planning scrutinised
Entitled Safeguarding our Seas: a strategy for the conservation and sustainable development of our marine environment, the report's promises include:
Mrs Beckett said: "More than 70% of fish stocks are either fully or over-exploited. Three-quarters of saltmarsh in England and Wales has been lost.
"Over 50% of the world's coral reefs are threatened by pollution, coastal development and climate change.
"'Safeguarding Our Seas' provides a coherent and integrated approach to tackle these threats to the marine environment. It shows how we are moving away from one-dimensional thinking by adopting an ecosystem-based approach."
Several marine groups have welcomed the strategy, but say they have reservations about it.
Cetaceans threatened
English Nature, which advises the government, said it was "concerned that the vision for sustainable fisheries may be at risk from pressure exerted on the European Commission by some member states".
These, it said, "do not support changes to the existing common fisheries policy (CFP) which would favour sustainable fisheries in EU waters."
Paul Knapman of English Nature said: "Fish stocks are on the brink of collapse, species such as dolphin and porpoise are being killed at unsustainable levels, and deep water fisheries are being subsidised without any regard to their devastating impact on the marine environment."
Dr Sharon Thompson of the Royal Society for the Protection of Birds told BBC News Online: "We welcome the strategy - we're very happy to see marine conservation high on the government's agenda.
"There are some very good things in it - the conservation of biological diversity, for instance, the ecosystem approach, and strategic planning.
"But will the environment department and the Department for Transport, Local Government and the Regions (DTLR) see eye-to-eye on what needs to be done?
'Inadequate response'
"It's DTLR that's proposing a new airport at Cliffe marshes in the Thames estuary, a very sensitive site. That's one of the things that worries us."
The Wildlife Trusts said the government was "dithering", and its recommendations were "far too little, too late".
It said the strategy did little to address the serious problems facing the marine environment now, and fell far short of what was needed in terms of action and funding.