I say trap and relocate them. But somehow ever so mysterily, they don't survive the trip.

Or another thought

Conduct a study of what the impacts on relocating them: $3,000,000.00
Conduct second study to figure out why they came right back: $10,000,000.00
One .223 round entering the brain of a sealion at 2000fps: PRICELESS or about $0.20 and the line forms behind me
_________________________
Netting = EXTINCTION