I speared my first fish (a pollack) by the rocks on the East side of Burgh Island.
I saw some reasonable sized mullet there as well right up close to the beach, and a small flounder by the river mouth.
An angler I spoke to told me he had seen two spearos swim round the island and come back with several large Bass. I don't know if this means it is safe to do so, but it certainly sounds like it's worth investigating.
Hope Cove is a good launch site and a fairly short boat ride away, so if a boat is a good idea I could bring one along