The price of a fish supper could rise in the coming weeks as a strike by Icelandic fishermen threatens the UK’s supply of fresh cod and haddock.

The dispute, which has been fuelled by currency swings following the Brexit vote, has now started to affect British fish industry jobs, with business owners warning consumers that price hikes could be on the horizon. The news threatens a further hit to consumers’ pockets as poor weather in Spain has caused a spike in lettuce, broccoli and aubergine prices.

“Since January we have had virtually no Icelandic fish,” said Martyn Boyers, chief executive of the group that operates Grimsby fish market, the UK’s biggest importer of fresh Icelandic fish. “We are currently down 75% on Icelandic fish in weight terms over the last five weeks. It’s putting pressure on jobs in the supply chain and availability in shops.”

The supply crisis has forced job cuts at the Grimsby market, with roughly one-fifth of staff let go – from 32 down to 26. “If this strike continues it will be a problem not just for us but for all people who receive Icelandic fish,” added Boyers. “Everyone in the supply chain will be affected and, if they do get fish, they will have to pay more for it. Cod and haddock are a staple part of the British diet.”

At Grimsby, the price of whole cod is £2.80–£3 per kilogram with haddock at £2.20-£3.30 per kg.

Kolbjorn Giskeodegard, a seafood analyst at broker Nordea, said the Icelandic strike’s fallout had raised the price of Norwegian cod, which was “extraordinarily high” in the wholesale market last month: “The price was up 40% to 50% on thin volumes,” he said, explaining that the shortage had been created not only by the Icelandic strike but a delay to the start of the Norwegian fishing season.

The Icelandic fisherman grounded their vessels over pay and conditions in December last year. A key area of tension is the chunk of the fishermen’s pay packet linked to their catch. The Brexit blow to the pound has been bad news for the trawlermen, who have suffered a sharp fall in income due to the swing in the exchange rate as the Icelandic kronor strengthened against the pound.

“The kronor has strengthened a lot [against the pound] over the last six to 10 months, said Haukur Thor Hauksson, deputy managing director of Fisheries Iceland. “So it follows that the income derived in kronor terms for both the ships and sailors has fallen. If you look back 10 months ago the pound was worth 200 ISK; today it is about 140. That’s a drop of 30% the sailors are seeing in the price going to the British market.”

Hauksson said parties from both sides were having constructive meetings to try to resolve the issue. “I can’t promise anything regarding the timeline but we are having good talks.”

The pressure on the fish price comes as supermarkets struggle to supply fresh vegetables. Last week, retailers started rationing iceberg lettuces while others banned bulk purchases of aubergines, broccoli, loose courgettes and cabbage. Even olive oil has been affected, with weather conditions in Italy and Spain causing double-digit rises in wholesale prices.

The shortages have started to affect the bottom line, with retailers selling 9% less iceberg lettuce – the UK’s most popular leafy salad – in the three months to the end of January. Rocket and spinach sales were also down 42% and 12% respectively, according to industry analysts Kantar Worldpanel.

To get their five a day shoppers have turned to cos lettuce, romaine and little gem, according to Kantar. Sales of kale soared 37% and cabbage lifted 4.2% as people turned to cheaper and more abundant vegetables. Sales of frozen vegetables such as peas, sweetcorn and spinach also rose 4% – almost £12m worth.