Usually in the first week of May, or a week prior, the first quality fish tend to move in. Not giants, they're usually around 10 to 20 pounds, but not little 14" fish.
The main reason the bass move up into the Bay is to take advantage of the feast that is there in the spring. Herring will be falling back out of the rivers, adult bunker are usually around, silversides, squid, mantis shrimp, worm hatches.
Many people liveline bunker for them or throw Black Saltys, but I like my Tsunami Shads. I just seem to catch more fish working the bottom with them then I do with bunker. But, it's definitely a lot of fun seeing a live bunker get crushed on the surface by a bass.
Tsunami Shads
In mid May or shortly after bigger fish start to arrive in the Bay. 25+ pound fish. And by late May there's usually a few 40's moving around. Early June, and if the bait sticks around, even later in the season the striper fishing can stay good in the Bay.
My favorite place to be is in the
whitewater and/or open ocean whether it's on shore or in a boat, so as soon as there are good fish outside the Bay, that's usually where I end up fishing. The Upper Bay often literally starts to stink as summer settles in.
Can't really tell you much about Fishers Island, it's an area I haven't fished more then a few times.