Increased global demand for squalene – a lipid used in cosmetics and vaccines – has led to a rise in shark deaths but olives could be a more sustainable source than shark livers, Olive Oil Times wrote on 19 July.

However, as olive-derived squalene was 30% more expensive than the alternative from shark livers, cost remained a factor, according to the report.

Although olives were becoming increasingly popular as a source of squalene in cosmetics, 90% of the industry still relied on shark liver oil, leading to 2.7M shark deaths annually, Olive Oil Times said.

Squalene and its hydrogenated counterpart, squalane, are used in cosmetics as emollients; and in vaccines as adjuvants, which boost the immune system response.

Approximately 2,500 to 3,000 sharks are needed to harvest one tonne of squalene, according to the Food and Agriculture Organization of the United Nations (FAO).

In contrast, the Olive Wellness Institute estimated that between 77 and 1,250 tonnes of olive oil (depending on the variety, extraction method and level of refining) contained the same amount of squalene. Extra virgin oil has the highest levels of lipids of any vegetable oil, according to the report.

A large proportion of the shark-derived version of this lipid came from bycatch, when sharks were unintentionally caught in fishing nets, Olive Oil Times wrote. However, the concern was that sharks were captured instead of being set free due to the demand for squalene, making it almost impossible to calculate how many sharks were caught exclusively for squalene.

With scientists racing to develop a range of COVID-19 vaccines at the end of last year, conservationists had expressed concern about the impact on shark populations as the demand for squalene increased, the report said.

While none of the approved COVID-19 vaccines used shark squalene, five of the 300 in development did, Olive Oil Times wrote.

The concern was that if Covid-19 vaccines containing squalene were widely approved and the coronavirus vaccine became an annual requirement, as some health experts were predicting, demand for the lipid would increase, the report said.