Missiles and eggs were thrown yesterday as Sinn Fein members of the North's cross-party Assembly agriculture committee toured the staunchly unionist village of Portavogie, on the Ards peninsula in Co Down.
They had travelled to Portavogie to talk to local fishermen.
RUC officers made a number of arrests at the harbour, and the committee chairman, the DUP leader, the Rev Ian Paisley, was taunted by protesters.
The committee continued on its day-long fact-finding mission to the Co Down fishing villages of Ardglass and Kilkeel.
Dr Paisley said fishermen were unable to take a viable catch from the Irish Sea under EU regulations and as a result the fishing industry was in a "calamitous state".
Local protesters told Dr Paisley and Mr Ian Paisley jnr they were angered that the DUP was associating with Sinn Fein. "We're trying to keep your husbands in jobs. I'm not going to stop doing my job because of Sinn Fein," Mr Paisley said.
Mr Francie Molloy (Sinn Fein, Mid Ulster) described the protest as "shortsighted and stupid". He said he and his party colleague, Mr Gerry McHugh, (Fermanagh and South Tyrone), wanted to see the plight of fishermen first hand.
"The strong point coming across from everyone is that there is an urgent need for a compensation scheme, because people are not being allowed to work," said Mr Molloy.
Mr George Savage (UUP, Upper Bann), deputy chairman of the committee, said local politicians were committed to helping the fisherman, but that the reversal of devolution would mean the Assembly could not go to Brussels to lobby for the beleaguered industry.
Mr David Ford, (Alliance, South Antrim) admitted it was "bizarre" that the committee was undertaking the fact-finding exercise against the backdrop of political turmoil.
"It is a shame we are going to lose this opportunity because of the refusal of people to move," he said.