It's interesting in a way - can simply denying that Spanish ships are fishing in UK waters do the job? Lying has got him this far, after all, and if this election has shown us anything its that the truth does not matter.
I think it can. No-one really cares about fish outside of Grimsby anyway. He was still banging on about 40 new hospitals this morning - it's not true, never been true, never will be but he repeats it ad nauseam. Will do the same for fish and whatever else now because he knows he can get away with it.