Sea pen culture is key to success

THE development of a reliable and manageable system of sea pen culture has been at the heart of Marine Harvest’s salmon farming success.

The first production pens went into the sea at the Loch Ailort site in 1971. And although they were very different to those now widely used by the company, some of those pens are still operating.

‘When designing sea pens suitable for rearing salmon the engineer must pay attention to seven key factors,’ Unilever’s Dr Robert Young told a recent Atlantic Salmon Conference. ‘A good pen must minimise the risk of fish loss; permit good water exchange; be of manageable size; give good access to the fish; be easily cleaned of fouling; be of minimum cost; and be capable of a long productive life.’

Grilse harvest

Smolt transfer to the sea units starts in May each year and ends in late June. First grilse are harvested exactly a year later and salmon are harvested any time after that depending on market demand. Most grilse are marketed at 1.5kg to 2kg (about the 4lb mark).

‘There has been a good, steady trade for grilse this year. This certainly helps the profitability of any salmon enterprise,’ said farms’ manager Dr Hillcoat.

Salmon at all but one of the Marine Harvest sea sites are hand fed. The exception is the Ephesus site in Loch Ailort.

‘There has also been considerable involvement in our expanding programme by the Highlands and Islands Development Board’, said Marine Harvest chairman, Dr Iain Anderson. ‘Fish farming is a business ideally suited to this part of the world and has proved to be one of the genuine job creating industries for the isolated west coast areas.’