Sandy Hook bay is loaded with them every winter. I've seen them in Raritan Bay but not as frequently. They usually leave the area right around this time. A few years back in the summer months I did see a Harbor Seal (I think that's what it was) and he hung out in the marina all summer looking for an easy meal when people were cleaning fish.
https://www.nps.gov/gate/learn/natur...ook-Waters.pdf
