While the United Nations' Convention on Biological Diversity has a goal of managing ocean resources sustainably by 2020, Dr Costello said this goal was looking less achievable, not more.
"Most people probably think we are making progress in marine conservation but the figures show that's not the case," Dr Costello said.
"So far extinctions in the ocean have been lower than on land but we know some marine species are on the brink and at least a ten-fold increase in no-take marine reserves is the best way to conserve marine biodiversity for future generations."
New Zealand protects 6.9 per cent of its marine environment through some form of protection but less than one per cent of our Exclusive Economic Zone - the world's fourth largest - was protected through no-take reserves.
Scientists know that more than 15,000 marine species inhabit our territorial seas and our EEZ, but there may be a further 50,000 yet to be found in our waters
On average, seven new marine species were identified every fortnight - something that would seem remarkable if not for the fact that less than 1 per cent of our marine environment had ever been surveyed.
Globally, less than one per cent of the world's oceans are designated no-take marine reserves and less than one quarter of coastal countries have even one designated marine reserve.
The latest study showed that, since 1950, 9,000 MPAs have been established by 150 countries, and today, just 6 per cent of those are no-take; in 1950 the figure was 27 per cent.
By 2013, a total of 94 per cent of MPAs allowed some fishing.
"MPAs are often multiple-use, with the aim of managing resources rather than preserving and protecting biodiversity in its wild condition," Dr Ballantine said.
"Only areas that are no-take should be regarded as truly protecting ocean ecosystems and if countries can't accurately report from no-take areas within MPAs, then conservation gain should be assumed to be zero."
Of the existing 9,000 MPAs around the world, protection measures vary.
"Any fishing tends to impact marine ecosystems and particularly if regulations for an MPA allow fishing of the largest animals which has a direct impact on population structure and therefore the ecosystem as a whole," Dr Costello said.
Discussion document due before overhaul of "cumbersome" legislation.
The Government is now working on a legislation overhaul to create a new Marine Protected Areas Act, and Environment Minister Nick Smith told a conference earlier this month that a discussion paper on it would be released later this year.
In a speech to the Environmental Defence Society's annual conference, Dr Smith said that the purpose of marine reserves were "way too narrow" and the mechanisms behind them were "cumbersome and divisive".
"We need to provide for a graduated approach to marine protection as is now world best practice and we need to recognise a wider range of marine species other than just marine mammals may be in need of sanctuaries."
While the Government had advanced 10 new marine reserves last year in areas like the subantarctic islands, the West Coast, Akaroa and Kaikoura, he said the "Marine Reserves Act passed during the Holyoake era is past its use-by date".
A recent DoC briefing stated the 1971 Act failed to provide for effective collaborative planning or recognition of the Marine and Coastal Area (Takutai Moana) Act 2011, or for a purpose other than scientific study to lead to the establishment of marine protected areas.
An overhaul would remove the need to use area-specific legislation and duplicate consultation to protect an area formally once the Government had accepted the work of forums set up by DoC and the Ministry for Primary Industries under the Marine Protected Areas Policy.New Zealand's ocean estate, more than 20 times its land area, spans 15,000 km of coastline and nearly six million square kilometres of ocean.
Despite this vast area, most Kiwis think the bulk of it is protected.
A survey co-authored by World Wildlife Fund-NZ and published in the journal Marine Policy, revealed many Kiwis hugely over-estimate our present level of protection.
On average, the public thought that less than 30 per cent of our marine environment was protected by no-take reserves, and that 36 per cent should be protected.
The study authors recommended more public education to highlight the actual levels.
Just under 10 per cent of our territorial sea, or waters within 12 nautical miles of the coast, is now protected by marine reserves - close to the target recommended by the UN.
But when compared against territorial sea and all 4.4 million sq km of our EEZ, a tiny amount is covered by protected areas, although any commercial activities beyond fishing are still subject to environmental regulations under the recently updated EEZ Act.
Just under a third of the EEZ was also covered by benthic protection areas, where bottom trawling and dredging is banned, while 2.5 per cent of our territorial waters are partially protected under another classification applying to cases such as cable and pipeline zones and area-based fisheries restrictions.
By comparison, around a third of our land fell within some form of protected area.
Fisheries Act review
Meanwhile, the Government was also reviewing the Fisheries Act, with an aim to increase greater net value to all sectors, while "enhancing" fisheries' sustainability, Primary Industries Minister Nathan Guy told Seafood New Zealand's 2015 conference last week.
The review would be "high level" could possibly include changes to fisheries management processes within the current legislation, regulatory change, and amendments to the Fisheries Act.
It would not be getting into the detail of aspects like bag limits or quotas, he said, nor would it undermine existing rights and interests of commercial, customary and recreational fishers, treaty settlements or core elements of the current Quota Management System.The Ministry of Primary Industry would be canvassing the views of stakeholder organisations over the next few weeks.
Recreational fishing advocacy group LegaSea responded to the review by today calling on the Government to broaden its focus to take into account the value of recreational fishing.
"The Government has called for seafood revenue to double by 2025 but we're already at the maximum amount of fish we can take out of the sea, so if we want to hit that target we need to change our focus away from taking as much as we can from the ocean and move towards higher-value activities," spokesman Scott Macindoe said.
The group believed recreational fishing had a "substantial economic value" despite only taking six per cent of New Zealand's total catch each year, and this needs to be recognised in any overhaul of the Fisheries Act.
