Scottish Fishermen's Federation Chief Executive Elspeth Macdonald addressed a letter to UK Prime Minister Boris Johnson Friday expressing the industry's anger over mounting financial losses faced by vessels as the Brexit fisheries deal comes to action.

Scottish seafood processors have expressed fears of being cut out of the supply chain as vessels head for ports in Denmark to land their catches to avoid disruptions following the United Kingdom's departure from the European Union on Jan. 1.

Macdonald said the final agreement falls well short of what the prime minister promised to the fishing industry from the final Brexit agreement.

"There is huge disappointment and a great deal of anger about your failure to deliver on promises made repeatedly to this industry," Macdonald said.

In a July 6 letter last year, Johnson took a strong posture on UK fishing rights, saying the government was "simply not prepared to agree to an arrangement that is manifestly unbalanced and against the interests of the UK fishing industry."

However, in the ultimate deal, the EU fleet will continue to have full and unfettered access to UK waters until the middle of 2026. If the United Kingdom wants to change the agreement at that point, the European Union can impose a suite of punitive sanctions.

Under the terms of the Brexit deal, the United Kingdom's quota share will rise from 24.5 percent to 32.2 percent over five years, "which can hardly be claimed as a resounding success," Macdonald said.

The industry is also concerned over the outcome of many key whitefish species, specifically North Sea cod and saithe.

"This industry now finds itself in the worst of both worlds," Macdonald said in her letter to Johnson.

The UK seafood industry has faced major logistical disruptions in getting fish market since the turn of the year.

In her letter, Macdonald called on Johnson to increase the amount of government support for the seafood sector to offset the additional costs and lost business.

Currently, the UK government is providing support to the fishing industry via a £100 million (€112 million/$137 million) fund.

"Your deal has failed the industry in the short term, but there is scope to rights its wrongs, and your government needs to commit to doing everything that it can to achieve this," Macdonald said.

"We will have another chance to revisit this in 2026, so there is much to do between now and then to prepare the ground for that."

The current priority, McDonald added in her letter is for the government to secure enough fish through talks with the European Union and Norway to "bridge the gap that your deal failed to, and [...] stem the losses that are mounting up and compensate those businesses already affected."