Some 31 marine conservation zones – covering an area around three times the size of Cornwall – will be given increased protection next year off the shores of England and Wales.
But the figure only represents a proportion of the 127 "underwater national parks" that were recommended by independent advisors to create a network of wildlife-protected sites in the UK's seas.
Off the South West coast, just 15 zones were signed off from 58 previously earmarked by the Finding Sanctuary independent body after two years' work. Padstow Bay, the Tamar Estuary and Torbay will be among the first wave. The zones, Labour's flagship environmental legislation in government, will protect wildlife ranging from seahorses to corals. Dolphins, basking sharks and pink sea fans are among the Westcountry wildlife poised for greater protection.
The plans drew criticism from fishermen and the shipping industry against claims they would jeopardise livelihoods and coastal regeneration.
Despite spending £8.8 million on the policy, the Department for Environment, Food and Rural Affairs (Defra) said the "poor state of evidence in the marine environment" has hindered efforts.
Indicating that opposition to plans has been taken on board, ministers also avoided backing sites that would "unduly compromise coastal development". A controversial MCZ in the Fal estuary, which the town council claimed would have threatened "350 years of history and shipping power", is not in the first tranche.
Under proposals put out for consultation, no areas will be given the highest level of protection as no-take zones – where all damaging activities such as fishing are banned.
Natural environment minister Richard Benyon said: "Designating the right sites in the right places, so that our seas are sustainable, productive and healthy, and to ensure that the right balance is struck between conservation and industry."
Former environment minister Ben Bradshaw, Labour MP for Exeter, said the announcement was "extremely disappointing".
He said: "The Government's own independent advisors said the original much bigger network would be required to be effective in protecting marine biodiversity.
"All those organisations with an interest in our seas spent two years identifying the areas. They now feel badly let down. Let's hope this is just a start."
Abby Crosby, marine conservation officer for Cornwall Wildlife Trust, said: "We are sad to see the loss of some of Cornwall's most fantastic sites, from Mounts Bay to the Gannel Estuary in Newquay.
"These areas highlight some of our most special wildlife, from dolphins and basking sharks to crayfish and pink sea fans.
"These areas will now have a delay in their much needed protection due to decisions made by UK government."
The Marine Conservation Society said 59 of the 127 sites were highly threatened and should be designated immediately – but just 22 of the at-risk sites were included.
Dr Jean-Luc Solandt, its senior biodiversity policy officer, said: "We wouldn't stand by and let wildflower meadows and ancient forests be dug up and cleared, and yet heavy fishing gear is dragged across all kinds of habitats, destroying large swathes of the seabed with very little control."
The South West 15 sites are: East of Haig Fras, North Devon; Southwest Deeps (West); The Canyons, Land's End; Lundy, North Devon; Padstow Bay and Surrounds; Isles of Scilly; The Manacles, the Lizard Peninsula; Upper Fowey and Pont Pill, South East Cornwall; Whitsand and Looe Bay off South East Cornwall; Tamar Estuary; Skerries Bank and Surround, South Devon; Torbay; Chesil Beach and Stennis Ledges, Dorset; South of Dorset; Poole Rocks, Dorset.
