For the past few decades fish stocks in the oceans around Britain have been depleting due to overfishing, causing a knock-on effect to other species.
Once-common species are now facing extinction, including the common skate, angel shark, sturgeon and leatherback turtle which are all critically endangered.
In order to protect the wildlife that is left, the Marine Conservation Society (MCS) want a third of UK waters to be designated as “no-take” nature reserves by 2020 as part of the Marine Bill currently going through Parliament.
Dr Jean-Luc Solandt, biodiversity policy officer for MCS, said: “We have dithered while Rome burns.
“Marine reserves are a cost-effective way to achieve benefits for wildlife and the fish species that rely on habitats being protected for the long term.
“It makes social, economic and ecological sense. We must no longer fear these simple and cheap methods to recover our seas and embrace their proven value for marine management.”
He warned that currently the Bill, which puts a duty on ministers to create marine conservation zones but does not indicate what they would look like or what level of protection they would receive, was “just window-dressing in terms of recovery and sustainability”.
In addition to the 30 per cent of the seas that should be protected as broad habitats, specialist areas such as sea grass beds and reefs should be safeguarded, he added.
A Defra spokesman said: “The Marine Bill is a new flexible tool which will allow us to provide better marine protection, for example through Marine Conservation Zones to safeguard rare and threatened habitats and species.
“Separately the UK wants to secure a sustainable Common Fisheries Policy which ensures both conservation of fish stocks and a living for fishermen and dependent industries.”