European and South American governments plan to intensify efforts to prevent a return to commercial whaling.
On Sunday the International Whaling Commission (IWC) passed a declaration calling for the eventual lifting of the 20-year global moratorium.
European and South American delegates told BBC News they now plan to recruit more anti-whaling countries into the organisation.
Japan is planning a meeting early next year to drive its campaign forward.
It will host a three-day summit, probably in January, open to nations which support its aim of “normalising” the IWC – by which it means returning the 60-year-old organisation to its original purpose of regulating commercial whaling.
“We are not trying to exclude, or separate or divide this organisation,” said Joji Morishita, Japan’s deputy whaling commissioner.
But in a clear statement of intent to vocal anti-whaling nations such as Australia and the UK, he warned: “We will not welcome the repetition of the polarisation of the IWC in this meeting – that will be very clearly stated and underlined.”
Following Sunday’s approval of the St Kitts Declaration, as the resolution is called, the onus is now on anti-whaling countries to intensify efforts aimed at ensuring Japan does not achieve the three-quarters majority of IWC members which it needs to overturn the global moratorium.
Such a powerful coalition remains a long way off, as demonstrated by the fact that Sunday’s resolution passed by the narrowest margin possible, a single vote.
Conservation groups have been urging Britain, Australia, the US and their allies to recruit more allies to their cause, either by lobbying pro-whaling IWC members to switch sides or by persuading more conservation-minded countries to join up.
Several groups identify the European Union as a natural recruitment ground.
Delegates from three EU nations, declining to be identified publicly, told BBC News they are already talking to the Union’s newest members.
“We have 14 of the 15 pre-enlargement countries in [the IWC] already, and only one of them supports whaling,” said one delegate.
“We have three of the  new members and we’re talking to the rest,” he said.
His reference to “only one” nation which supports whaling was a scarcely-veiled criticism of Denmark, whose vote in favour of the St Kitts Declaration proved crucial.
In fact Denmark adopts pro- and anti-whaling positions on different motions, and is in the position of representing both Denmark itself, and Greenland and the Faroe Islands where whaling is supported.
Some delegates from other European countries professed themselves amazed by the Danish position on such a key issue, and may ask ministers to “have a word” with their counterparts in Copenhagen.
WWF labelled Sunday “Denmark’s day of whaling shame”.
There is likely to be a new recruitment drive in Latin America as well, according to Brazil’s commissioner Maria Theresa Pessoa.
“We have been doing it already, together with Argentina,” she told BBC News.
“We met in Buenos Aires last October with a number of Latin American countries that are not members of the IWC but might have an interest in joining or re-joining; and we are talking with these countries, and hoping that we will gather the necessary conditions for them to become part of the IWC and attach themselves to our thesis.
“Eventually we will [achieve a majority]. I don’t think that the resumption
of commercial whaling is acceptable for world opinion in the 21st Century.”
Brazil sees the development of ecotourism as particularly valuable for Latin American countries.
Flushed by its victory on Sunday, Japan decided not to seek censure of Greenpeace over what it calls “interference in scientific research”.