Science: Salmon and spice, and no sign of lice: Garlic's potent properties are helping fish farmers in the war against parasites, says Danny Penman

Garlic may turn out to be the unlikely saviour of the Scottish salmon industry by acting as an eco-friendly pesticide, say researchers at Liverpool University.

Scientists at Liverpool and in the Shetlands have discovered that salmon lice, which cost the industry more than pounds 10m a year in lost production, hate the smell of garlic.

The lice find victims through their acute sense of smell. If salmon are given food containing garlic extract - equivalent to several cloves - the powerful odour confuses the lice, which fall off their hapless victims.

The fish apparently love the nouvelle cuisine and are happy to eat it three times a day as required. The salmon smell of garlic, but a few days in clean water gets rid of the taste from the fish.

At present, sea lice are controlled by a group of pesticides known as organophosphates. Farmers in the Faeroes were the first to experiment, using onions to replace the expensive and environmentally damaging man-made chemicals employed in salmon farming.

At first, the idea of using onions was met with derision, as Chris Young of the Shetland Salmon Farmers Association explains: 'It was viewed with some hilarity at the time - but on the other hand, anything was worth a try.'

Mr Young contacted researchers at Liverpool University to investigate the farmers' claims. Dr Hamish Collin, senior reader at Liverpool University, said: 'A preliminary study found that onions were not particularly effective, but then we decided to try garlic.' This proved effective, and held promise as an organic pesticide.

From there, a grant from the university funded a larger study to provide the necessary hard evidence for a grant application to the Government's Clean Technology Unit (CTU). Dr Collin said: 'The CTU wants to reduce the amount of chemicals being added to the environment - so we went ahead and did the trials in the Shetlands and those were successful.'

Farmers have tried other environmentally friendly ways of controlling salmon lice. The most successful alternative is the salmon lice predator, wrasse, which eats the lice, but can introduce other pests and diseases.

Alastair McIntyre, professor of fisheries and oceanography at Aberdeen University, said: 'There has been a movement to employ organophosphates where possible as something more environmentally friendly (than organochlorines), but nevertheless they are in fact biocides - designed to kill.'

The two main dangers, according to Sian Pullen, marine conservation officer for the World Wide Fund for Nature (UK), is that they kill animals other than sea lice, and pose a health hazard to salmon farmers.

Ms Pullen says: 'The effect is small-scale, but the problem is you have salmon farms in virtually all of the sea lochs on the west coast. Although the effect may be fairly localised, the cumulative result of this in fish farms all the way up the west coast is quite high.'

The organophosphates do not infiltrate the food chain and affect humans. However, they can wipe out a whole layer of the food chain, with devastating local effects, Ms Pullen says.

Another alternative is being developed by scientists at Aberdeen University who are trying to produce a vaccine to protect the fish. The idea is simple in theory but complex in practice. The scientists hope to isolate proteins from the lice that are capable of provoking an effective immune response in the fish. This would allow them to make the proteins artificially and then produce a vaccine.

If the final research at Liverpool proves successful, then the door is open for similar natural compounds to replace the plethora of man-made chemicals used by farmers and aquaculturists alike. Mr Young said: 'Nobody likes to be using any chemicals at all - so an organic, environmentally sound compound would be most welcome.'

(Photograph omitted)

Suggested Topics
News
people'It can last and it's terrifying'
Sport
Radamel Falcao
footballManchester United agree loan deal for Monaco striker Falcao
Sport
Louis van Gaal, Radamel Falcao, Arturo Vidal, Mats Hummels and Javier Hernandez
footballFalcao, Hernandez, Welbeck and every deal live as it happens
Sport
footballFeaturing Bart Simpson
PROMOTED VIDEO
News
peopleA spokesperson said the support group was 'extremely disappointed'
Voices
A man shoots at targets depicting a portrait of Russian President Vladimir Putin, in a shooting range in the center of the western Ukrainian city of Lviv
voicesIt's cowardice to pretend this is anything other than an invasion
News
i100
Arts and Entertainment
Alex Kapranos of Franz Ferdinand performs live
music Pro-independence show to take place four days before vote
News
news Video - hailed as 'most original' since Benedict Cumberbatch's
Arts and Entertainment
booksNovelist takes aim at Orwell's rules for writing plain English
News
ebooksAn unforgettable anthology of contemporary reportage
Arts and Entertainment
The eyes have it: Kate Bush
music
News
i100
Life and Style
tech

Apple agrees deal with Visa on contactless payments

Life and Style
techIf those brochure kitchens look a little too perfect to be true, well, that’s probably because they are
News
i100
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Technical Software Consultant (Excel, VBA, SQL, JAVA, Oracle)

£40000 - £50000 per annum: Harrington Starr: You will not be expected to hav...

Technical Sales Manager

£45000 - £53000 Per Annum plus bonus plus package: The Green Recruitment Compa...

Humanities Teacher

£110 - £135 per day + Competitive Rates: Randstad Education Maidstone: Outstan...

SQL DBA/Developer

£500 per day: Harrington Starr: SQL DBA/Developer SQL, C#, VBA, Data Warehousi...

Day In a Page

Alexander Fury: The designer names to look for at fashion week this season

The big names to look for this fashion week

This week, designers begin to show their spring 2015 collections in New York
Will Self: 'I like Orwell's writing as much as the next talented mediocrity'

'I like Orwell's writing as much as the next talented mediocrity'

Will Self takes aim at Orwell's rules for writing plain English
Meet Afghanistan's middle-class paint-ballers

Meet Afghanistan's middle-class paint-ballers

Toy guns proving a popular diversion in a country flooded with the real thing
Al Pacino wows Venice

Al Pacino wows Venice

Ham among the brilliance as actor premieres two films at festival
Neil Lawson Baker interview: ‘I’ve gained so much from art. It’s only right to give something back’.

Neil Lawson Baker interview

‘I’ve gained so much from art. It’s only right to give something back’.
The other Mugabe who is lining up for the Zimbabwean presidency

The other Mugabe who is lining up for the Zimbabwean presidency

Wife of President Robert Mugabe appears to have her sights set on succeeding her husband
The model of a gadget launch: Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed

The model for a gadget launch

Cultivate an atmosphere of mystery and excitement to sell stuff people didn't realise they needed
Alice Roberts: She's done pretty well, for a boffin without a beard

She's done pretty well, for a boffin without a beard

Alice Roberts talks about her new book on evolution - and why her early TV work drew flak from (mostly male) colleagues
Get well soon, Joan Rivers - an inspiration, whether she likes it or not

Get well soon, Joan Rivers

She is awful. But she's also wonderful, not in spite of but because of the fact she's forever saying appalling things, argues Ellen E Jones
Doctor Who Into the Dalek review: A classic sci-fi adventure with all the spectacle of a blockbuster

A fresh take on an old foe

Doctor Who Into the Dalek more than compensated for last week's nonsensical offering
Fashion walks away from the celebrity runway show

Fashion walks away from the celebrity runway show

As the collections start, fashion editor Alexander Fury finds video and the internet are proving more attractive
Meet the stars of TV's Wolf Hall... and it's not the cast of the Tudor trilogy

Meet the stars of TV's Wolf Hall...

... and it's not the cast of the Tudor trilogy
Weekend at the Asylum: Europe's biggest steampunk convention heads to Lincoln

Europe's biggest steampunk convention

Jake Wallis Simons discovers how Victorian ray guns and the martial art of biscuit dunking are precisely what the 21st century needs
Don't swallow the tripe – a user's guide to weasel words

Don't swallow the tripe – a user's guide to weasel words

Lying is dangerous and unnecessary. A new book explains the strategies needed to avoid it. John Rentoul on the art of 'uncommunication'
Daddy, who was Richard Attenborough? Was the beloved thespian the last of the cross-generation stars?

Daddy, who was Richard Attenborough?

The atomisation of culture means that few of those we regard as stars are universally loved any more, says DJ Taylor