Peterhead Fish Market has had no auction for the first time in recent history following a boycott by processors.
The Aberdeenshire town is the biggest white fish port in Europe and the market is one of the largest.
The dispute centres around Peterhead Port Authority's decision to stop certain buying practices which it said are anti-competitive.
It operates as a traditional shout auction with processors bidding for boxes of fish landed at the harbour.
Until recently, as part of that, the practice of so-called bid sharing or ringing was commonly used, which is when buyers sometimes bid in groups rather than individually.
However Peterhead Port Authority, which runs the market, is putting a stop to this.
It said that following complaints, it obtained legal advice which described such practices as "anti-competitive and contrary to applicable competition law".
In a letter sent in December to those who use the market, the port authority chief executive Simon Brebner said: "'The measures, which have the support of the fish selling agents, are intended to ensure therefore that in the interests of all stakeholders the sales process at the fish market is conducted in a compliant manner."
The authority insists each bidder should be acting independently and not co-operating with any other party to achieve prices at the auction which may be lower than those which would otherwise be achieved in a "genuinely competitive" market.
The move angered many processors and they responded by boycotting the market.
The Scottish Seafood Association, which represents the majority of processors, said the situation was ongoing and declined to comment.
BBC Scotland understands it is seeking legal advice on the matter.
The Scottish White Fish Producers Association, which represents fishermen, said it was "looking for both parties to sit down to find a workable solution to what isn't an unsurmountable difference".
The market is expected to operate as normal on Thursday. It is unclear if there will be further boycotts.