Two US scientists say they have managed to trace the life of a whale from its conception in the north Atlantic to its sale as raw meat in Japan 29 years later.

The BBC's Corinne Podger reports on the genetic monitoring programme

The scientists, from the Center for Conservation and Evolutionary Genetics at Harvard University, reported their work in the journal Nature.

They began by studying 69 grams of whalemeat bought in 1993 in a department store in Osaka, during a survey of Japanese whale markets.

Hybrid of blue and fin whales

Analysis of material in the meat's nuclear and mitochondrial genes showed that it came from a blue whale, or at least that the mother had been a blue whale - as mitochondrial DNA is inherited maternally.

The scientists, Frank Cipriano and Stephen R Palumbi, checked genetic databases, and found that the sequence analysis of the meat exactly matched that of a whale referred to simply as "26".

They established that "26" had a blue whale mother and a fin whale father. Ear-plug growth layers showed it was born in 1965.

It was killed off the coast of Iceland on 29 June 1989 as part of a four-year Icelandic scientific whaling programme.

There was a record of its death, though the whereabouts of the meat from "26" had not previously been known.

To confirm that the meat in the market was indeed from "26", the scientists carried out further tests. These showed that the meat contained distinctly different characteristics of both blue and fin whales.

Analysis of similar material from an archived sample taken from "26" when it was alive showed an identical match, confirming the scientists' belief that the animal had been the source of the meat.

They say alternative explanations, such as the possibility that there are many blue/fin hybrids in the north Atlantic, seem much less likely.

In principle, they say, further development of their work "could allow courtroom-level confidence" in identifying products from individual whales.

Genetic profiles compared

The scientists say a genetic monitoring programme would allow the documentation of traces of a whale from hunt to market, by comparing genetic profiles at the market with those of registered animals.

They say their results show that the use of several genetic markers now available for whales would allow individual animals to be tracked through international commercial channels.

That would improve the control of whaling, which has "loopholes in the current regulatory network large enough for protected whales to slip through".

End of an era

The death of "26" brought to an end an extraordinary chapter in marine biology - blue/fin hybrids are hardly ever reported.

Although fin whale numbers appear to be slowly recovering from years of industrial whaling, the blue whale - the largest creature ever to have lived on earth - remains extremely rare.

Cetacean experts said the existence of another blue/fin hybrid about five years ago probably meant that the blue had been unable to find a mate of its own kind.

Whales are supposed to be protected by two international bodies, but "26" was legally caught and sold.

The International Whaling Commission (IWC) imposed a global moratorium on commercial whaling in 1986. However, member states can catch any number of any whale species they choose, so long as they do it for what they describe as scientific study.

When "26" was harpooned, Iceland was still a member of the IWC - and there was nothing in the rules to stop it selling the meat from this rarest of whales to anyone it wanted.

The UN's Convention on International Trade in Endangered Species (Cites) controls the sale to foreign countries of products from protected species, including Whales.