Leaving the EU's failed Common Fisheries Policy is one of the most important benefits of Brexit.
All fish stocks in UK waters will be fished at sustainable levels after Brexit, the government has said as it publishes new legislation on fisheries.
The Fisheries Bill being introduced into parliament creates the powers for the UK to operate as an independent coastal state and manage its fish stocks.
It contains a legal guarantee the UK will quit the EU-wide Common Fisheries Policy (CFP) at the end of the transition period in December 2020.
But Sarah Denman, an UK environment lawyer at ClientEarth, said the bill fell "far short" of the government's election manifesto promise to secure sustainable fisheries.
She said: "The upcoming fisheries negotiations with the EU will be an important test to see if the government is serious about managing our fisheries sustainably for the benefit of the marine environment and coastal communities.
"In the face of the climate and ecological emergency, the UK urgently needs to show much greater ambition to protect, preserve and restore our marine environment."
Patrick Killoran at Greener UK said: "The additional focus on climate change and sustainability is very helpful, as it recognises that vibrant fisheries create a healthier wider environment."
But he added loopholes must be closed that allowed ministers to exceed fishing limits.
"The focus we can expect on rights and access over the next few months must be matched by more detail on how the Government will actually ensure sustainable fishing," he said.
At present, the CFP dictates how much British fishermen can catch and where, and fishermen have often complained they do not get a fair share of what is caught in UK waters.
The new legislation will end the automatic right of EU vessels to fish in British waters, with access to fisheries set to be a matter for the UK to negotiate in the future.
Foreign vessels will have to be licensed and follow rules set by the UK if they fish in British waters.
The Bill's publication comes in the wake of a warning fromLeo Varadkar, the Irish Prime Minister, that Brussels would look for concessions on fishing in exchange for the UK's financial services industry to have better access to the European single market.
It contains a legal requirement for all fish stocks to be fished at sustainable levels, and aims to ensure species such as dolphins are protected and bycatch of unwanted fish is reduced.
It will allow for management plans that are more tailored to the UK's mixed fisheries, where different fish stocks swim together, and that take into account the whole marine environment, officials said.
There are also measures on "climate-smart fishing" to consider the impacts of climate change on fisheries - which could see fish move or struggle in the face of rising temperatures - when managing stocks.
The plans also recognise that many fish stocks are shared with other countries, which will mean negotiation is important to ensure sustainable catches.
It includes new measures for devolved governments and a single set of UK-wide objectives to ensure fish stocks, and the marine environment, are better protected, Defra said.
Theresa Villiers, the environment secretary, said: "Leaving the EU's failed Common Fisheries Policy is one of the most important benefits of Brexit.
"It means we can create a fairer system which will allow marine habitats to thrive, with new powers to support our fishing sector and conserve our wonderful Blue Belt at home and abroad."
George Eustice, the fisheries minister, said: "The Fisheries Bill gives us the powers to implement our own independent fisheries policy, improve our marine habitats and make decisions based on the health of our fish stocks, not vested interests.
"For many people in coastal communities, taking back control and leaving the Common Fisheries Policy is at the heart of getting Brexit done, and this Bill delivers for the environment, fishermen and the Union."
Emily Beament is the PA environment correspondent.