Richard Lochhead questioned Lord Davies's fishing knowledge
The Scottish fisheries secretary has accused the UK government of "rubbing salt into the wound" after refusing to let him attend a European meeting.
Richard Lochhead said informal talks in Spain, which are being attended by a House of Lords representative, will now include more important issues.
A report on the future of the Common Fisheries Policy is to be discussed.
First Minister Alex Salmond has written to Prime Minister Gordon Brown to ask him to reverse the exclusion.
Mr Lochhead had asked to go but was refused permission by UK Secretary of State Hilary Benn.
Instead, the representative will be Lord Davies of Oldham, a parliamentary under-secretary of state at the UK rural affairs ministry Defra.
Mr Lochhead said: "Last month's cancelled fishing negotiations in Luxembourg had been scheduled to discuss issues of immense importance to Scotland and now these agenda items have been added to the informal meeting in Vigo that Scotland is barred from attending.
"This rubs salt into the wound caused by the UK government's decision to stop Scotland attending in favour of an unelected Lord whose knowledge of Scots fishing could probably fit onto the back of a postage stamp with lots of room to spare."
He said the fisheries policy "has failed" the industry and repeated calls to return "key decision-making" to Scotland.
A Defra spokesman said the department was required to represent the UK at the meeting and as such Lord Davies was attending as a minister.
Mr Salmond's letter to Mr Brown states: "As you know, Scotland's fishing industry represents over 70% of the UK's as a whole, and it is disgraceful that the nation of the UK with the strongest interest in the issues at stake should be excluded from the Vigo talks, with the elected Scottish fisheries minister refused attendance by Defra even at a time when a UK fisheries minister is not available."