The U.K. fishing industry voted overwhelmingly for Brexit ; 92% voted Leave according to a poll from June 2016 (source : The Guardian).
Now they are bleating about the massive logistical and administrative problems and delays that they are encountering in trying to export their catch into EU markets. Today, fish transportation companies have been driving their lorries around central London to protest about the situation.
But this is what they voted for : to ‘take back control of our waters’. They voted Leave in the full knowledge that most of the U.K. catch was exported to Europe, and that that would obviously be more difficult after Brexit, so they should suck it up & stop whinging.