Grieg lice numbers down nearly 90%

SHETLAND based Grieg Seafood has recorded a drop of nearly 90 per cent in numbers of adult female sea lice over the last year, the Shetland News reported.
Managing director Grant Cumming said a variety of factors, including new farming methods and colder sea temperatures, had helped to cut numbers of the parasite.
Grieg Seafood harvested 1,201 tonnes during the first quarter of 2018 in its region, which includes the isles as well as Skye, compared to 1,293 tonnes the previous year.
‘We produced a loss for the first quarter, which is disappointing, but we had a very low harvest volume, which is the main reason for showing a loss,’ Cumming said.
But there was an 87 per cent reduction in adult female sea lice in Shetland compared to the first quarter of 2017.
‘We’re making a lot of changes to how we farm fish,’ said Cumming, who recently appeared before the Scottish parliament’s Rural Economy and Connectivity committee, as part of its investigation into salmon farming in Scotland.
He explained to MSPs that he had consolidated Grieg’s operations, reducing the number of active farms, to help bring lice numbers in Shetland under control.
He told the Shetland News yesterday: ‘So there’s longer fallow periods, and farm management agreements with our neighbours that are more robust than they were in the past.
‘But in addition to that, being able to treat our sea lice with freshwater has made a big difference to us too.’
Cumming added that the sea in and around Shetland has been colder than the last four or five years – below seven degrees for the most of March – which has stunted the growth of lice.
‘Other things that we’re doing is that we’re using a lot of cleaner fish to eat sea lice off our salmon, so going forward all our sites will be stocked with cleaner fish,’ he said.
‘And most of sites are being stocked as well with something called a sea lice skirt, which is a six metre deep tarpaulin which goes around the pen.’
Grieg’s accounts, meanwhile, were down by an extra £900,000 due to a feed barge sinking in Skye in November.
Cumming said it is unclear why the barge sunk and confirmed that it will be raised in the summer.
Picture: Grieg Seafood managing director Grant Cumming