"[Monitoring] had been considered essential to get on top of by-catch, waste, under-reporting and non-compliance ... The new Labour Government has shown itself, in this move, to be no friend of science, or conservation either."
Nash said delaying the rollout of cameras and electronic monitoring would not see more dolphin deaths.
"The new technology doesn't determine what's going to be in the net. It will highlight if fishers are catching dolphins and not reporting that, but there's nothing in the electronic monitoring that will prevent dolphins from being caught."
Rose accused Nash of being in the pocket of the "powerful fishing lobby", but Nash rejected that.
"Everyone in the industry acknowledges that we have an issue with by-catch, and we have to deal with it. But I would rather delay this and deal with all the issues than roll out something that is half-baked and hasn't got buy-in by the people required to use it."
He said the system was not being cancelled, but would be improved in consultation with all stakeholders.
"This is an important initiative to get right, and we will not be following the hasty timetable set by the previous Government.
"If we get it wrong, the level of compliance will be patchy at best, and that's the last thing we want."