Police are investigating after more than 4,000 fish at a trout farm died.

The fish at the Glen Wyllin trout farm were killed because the compressor which regulates oxygen in the water was deliberately turned off.

The incident occurred early on June 11, but has only just come to light as police appeal for information.

Production manager Tim Knighton said: ’It’s hard to put an exact figure on the value, but it’s at least £200,000, which will take the company at least three years to recover the fish lost.’

The farm sells the eggs to more than 50 countries all over the world. Mr Knighton told the Examiner he doubted anyone deliberately set out to kill the fish and possibly didn’t understand what would be the result of their actions.

The effect of the compressor being switched off was that the oxygen level was severely depleted and many of the fish were killed.

The farm reuses 90% of its water and, without the compressor, the water becomes starved of oxygen.

Mr Knighton said: ’We came in on the Monday morning and it was switched off.

’The farm manager then discovered that 4,372 brood stock with a predicted harvest of 15,000,000 eggs which we would normally have available for sale from October were dead.’

He explained once a person accessed the area, it would not be difficult to locate and switch off the machine, saying it basically has an on/off switch.

But he believes noise complaints over the compressor could possibly be linked to what happened.

He added: ’We were using a back-up compressor because the main one was waiting to be repaired, which was difficult during TT.

’We had some complaints over the noise of the machine. It wasn’t so much loud, you could stand and talk next to it, but people at the Glen Wyllin campsite were complaining about it.’

During TT, one visitor told Isle of Man Newspapers the noise was like ’living near a building site’.

Mr Knighton confirmed environmental health officers were aware of the noise issue, but accepted the farm’s reasoning that it was difficult to have the main machine repaired during the TT fortnight.

In a tragic turn of events, the piece needed to repair the main machine arrived on the island on Thursday of race week and was due to be fitted on the Monday morning that the fish were killed.

Mr Knighton said the events are ’pretty horrendous’.

’It’s very sad. Obviously it’s sad because of the fish, but also because it’s people’s livelihoods and we’ll now have to let customers down.’

The incident is being investigated by Peel police. Anyone with information should ring 842208 or Crimestoppers on 0800 555 111.