OK - So according to Billfisher & his "empirical evidence" that spill over is "unlikely" unless it isn't a well managed fishery (with lots of assumptions)
What is a well managed fishery ? - closed seasons , even lower bag / possession / boat limits , greater restriction on tackle , more slot / size limits - reduced commercial quotas …….. all of which play their part.
I guess if you make it less worth while to go for a fish - then less effort would see fish numbers stabilise & increase .
There are already a lot of these "fishery management " tools in place ……. & yet "anecdotally" fishing is getting harder , fish quality is diminishing & there is a need to travel further & wider .
But somehow locking down areas is "unlikely" to help improve things
Chris
PS - This makes for a pretty reasonable read - on the current science / data collection