New Zealand is unlikely to compromise on its protection plan for the Antarctic's Ross Sea at key talks this year, out of concern that harsher measures on fishing would scupper a deal with other nations.
Twenty-five countries will meet in Germany in July for a last-ditch attempt to establish an enormous marine protected area in the region - 3500km south of New Zealand - after talks in November failed.
The meeting was hugely significant. It was only the second time the Commission for the Conservation of Antarctic Marine Living Resources had held a special interim gathering.
Foreign Affairs Minister Murray McCully said it was crucial to gain a consensus on protection.
"We need to nail it. This is the best chance we're ever going to have of [securing a protected area].
"If there's any room for further delay, then we have risk. This is by no means a done deal, and the worst outcome is to have no [agreement] at all."
The joint US-NZ proposal on the table is a 2.27 million sq km protected area which included a tag-and-release programme on the Ross Sea's continental shelf, where the highest concentration of toothfish were found.
Conservationists were concerned that this agreement was too heavily weighted towards commercial fishing. The research zone would require three toothfish to be tagged and released per tonne caught by commercial fisheries, so around 10 fish would end up on restaurant plates for every fish tagged for research.
The US-NZ plan also proposed a no-fishing zone in a crucial spawning area in the northwest of the Ross Sea. However, this no-take rule only applied during autumn, winter, and spring - when no fishing took place.
Antarctic Ocean Alliance co-ordinator Geoff Keey said the proposal was a start. He said it was encouraging that the spawning zone and the continental shelf region had been recognised as areas that were sensitive to overfishing.
Mr McCully said that significant amounts of work and compromise had gone in to making the joint proposal, and altering it could lead to another failed consensus. "I'm particularly concerned to keep the proposal intact. We don't want people unpicking things from here.
"I can't rule out further changes but you've got to remember that there are 25 countries sitting around this table and some of them only have fishing interests to protect.
"While I can understand that people feel passionately about the need to move the balance further towards conservation values, the fact is that you're not going to get 25 countries to agree to that."
Mr McCully expected no changes in the US stance on a marine reserve as a result of John Kerry's nomination as replacement for Hillary Clinton as Secretary of State. Ms Clinton was known to be passionate about Antarctica and conservation.
Seafood Industry Council spokesman Don Carson said his organisation would oppose any measure that led to a smaller catch. Three New Zealand ships caught around 730 tonnes of toothfish last summer out of a permitted take of 3800 tonnes for all countries.
That catch was worth $20 million to the New Zealand fishing industry out of total exports of $1.5 billion.
Mr Carson argued that tag-and-release programmes at McMurdo Sound did not reflect the population's health throughout the Ross Sea.
The US-NZ plan for the Ross Sea
*2.27 million sq km marine protected area, the largest in the world.
*1.6 million sq km no-take zone.
*Special research zone which requires 1 in 10 fish caught by fisheries to be tagged and released.
*Catch in the special zone cannot exceed 1450 tonnes in a five-year period or 500 tonnes in one season.
*Fishing in the special spawning zone only permitted between December and March.
*Timeframe for the marine reserve is open to negotiation.