there are Pike in Cochichewick???
Yes (I have witnessed
ONE).
As far as resident only, technically true:
http://www.townofnorthandover.com/pages/nandoverma_dpw/wtp/boating
I am not a resident, but I've fished there for years, no one bothers you there, it's not pressured due to access/electric only/not a lot of shore fishing. You will also notice hundreds of Jon's and other small craft along the shoreline (that's North Andover for you/see Brooks School).
I don't fish there much since purchasing a boat, but it gave the kids and I many days of enjoyment (my son caught his best there).