...it says here in the Cat Chron.   Someone has written in that a chap had his 2 rods confiscated and a 600 euro fine for using dead squid bait as it is not natural fauna in the Ebro.  It seems dead and live baits are illegal (I don't object to the live bait bit) as are any baits which are not indigenous and local.  Presume this means bread crust is OK and perhaps worm or maggot but anything else ain't.  Just another thing to send angling-tourists off to France or Ireland ??  Daft or what? 
Presumably the Agents Rurals are a self-funding organisation judging by the size of the fines they're allowed to deal out.