Green groups gathered in Malaysia are calling for urgent action to safeguard the world's oceans.
Reports being presented at a UN-led intergovernmental conference on biodiversity are highlighting damaging fishing practices, over-fishing and the lack of protection for the high seas.
Campaigners say three quarters of the world's seas are over fished
However, some Western governments attending are expected to resist extending environmental laws and conservation areas to cover international waters.
The planet's oceans are worth almost $80bn a year to the world economy in terms of fishing alone.
But according to environmental campaigners, only around 0.5% of their area is protected - and that protection, they say, is under-funded.
Reports out from groups including the WWF (World Wildlife Fund) and the Natural Resources Defence Council say that seabed trawling - where heavy chains, nets and steel plates are dragged along the sea floor - is devastating marine habitats.
Yet they say very few fish are caught this way so stopping it would have little economic impact.
Campaigners also reckon that three-quarters of the world's seas are over fished yet they estimate $20bn a year are given to fishing fleets in subsidies.
They are calling for some of that money to be channelled instead into conservation.
The cost is not just being counted in terms of species lost.
Given that almost half of the anti-cancer drugs currently under test are said to have marine origins, campaigners say we would be losing the medicines of the future.
However, environmentalists are expecting some resistance from governments who fear that moves at the conference to protect international waters could harm their fishing industries.