From the Hunting and Trapping Guide:

Trap and Target Shooting
Trap or target shooting on any state property or public hunting area is prohibited unless the area is a designated shooting range.


I don't think it would be too much of a stretch to interpret CT waters as "state property". At the very least I'd foresee getting pinched for illegal dumping and/ or breach of peace by CG/local/State PD......my.02