The government has admitted moving slowly to protect wildlife in the seas because of the cost.
Environment Minister Richard Benyon said that in the current financial squeeze he could not designate as many areas for protection as he would like.
He said he was hoping to confirm the designation of the current tranche of 31 Marine Protected Zones under a consultation that ends on Sunday.
Environmentalists have accused the government of dragging its feet.
This is because 127 zones were originally nominated for protection after a compromise deal agreed with other users of the sea.
Jolyon Chesworth from the Wildlife Trusts said: "We are disappointed at the rate of progress. The government has an international obligation to protect wildlife in the seas.
"The marine environment is not as obvious to people as it is when they see wildlife walking through a woodland or downland but it's just as important and equally worthy of protection.
"The 127 zones were only nominated after very long discussions with anglers, sailors and the fishing industry. We are now being asked to compromise on a compromise."
But Mr Benyon told the BBC that with cuts to the Defra budget, the cost of making scientific assessments and then developing rules for the use of different areas could not be dismissed.
"We are constrained by a hugely expensive process at a time when we have little money in government", he said.
"I want to do as many zones as we can for as little as we can. People have waited many years for this; we will designate the first tranche in September and will announce the next lot for consultation then."
Environmentalists are worried that the UK might slither back from its international commitment to create an ecologically coherent network of sites.
They are angry that several key sites have been left out of the first tranche on the grounds that insufficient evidence was supplied to justify them.
Sailors' fears
Mr Chesworth said that in his south of England region there was a cast-iron case for designating, among others, Bembridge Levels on the Isle of Wight - home of the stalked jellyfish and Poole Harbour - a key breeding ground for sea horses.
But both of these zones have been contested by sailors who fear that new rules will prevent them anchoring on sensitive sites. One boat owner on the Isle of Wight told Mr Benyon that the designations were "bonkers".
Boaters are the mainstay of the local economy and have lived in harmony with wildlife for decades, he said.
John Pockett from the Royal Yachting Association told the BBC: "We fear we won't be able to anchor our yachts; we fear we won't be able to train our next Ben Ainslie (the Olympian) because we won't be able to anchor marker boats."
Sailors are not the only ones protesting. In some areas fishing crews object to MPZs, even though they are supposed to provide a breeding ground for fish stocks to recover.
Conservationists warn that recently revealed chalk arches off the North Norfolk coast could be destroyed by one careless pass of a trawl net.
A further complication is the fact that UK jurisdiction ends six nautical miles from the shore, even though its responsibility for wildlife stretches further.
"It would be terrible to stop our own fishermen from exploiting a sensitive areas then allow boats of other nationalities to come in", Mr Benyon said. "We are trying to negotiate this with Brussels."
The proposals stem from the 2009 UK Marine Bill. If all the sites had been approved, just over a quarter of English waters would end up under some kind of protection. Currently, the total is way under 1%.
Globally just 0.6% of the world's oceans have been protected, compared to almost 13% of our planet's land area.
Marine author Callum Roberts told the BBC: "There's no way you'll have an effective network of marine-protected areas the way we are going. It's undermining trust."
But public sector cutbacks are a reality. And the government insists that the state of the economy will inevitably be felt on the sea bed, like everywhere else.