I just wrapped the hook bait in shrink wrap and also used fake corn and kept re-casting every 1.5hours during the day to check the bait.
There are lots of ways to get round the crays.
Have a general search

There are literally thousands of crays in most of the lakes, some monsters too.
Put a little bait close in the margins and have a look at night, I couldn't believe how many there was.
The bayliff came round and we said about it so he opened up the back of his jeep to show us a create full of crays he just caught from the traps.
He also said he has removed about 5thousand a month ago but that made little impact.