I googled Portsmouth co-op and all the articles that came up were about it closing, but they were all from 2002. I haven't been there this year (freezer is full of macs), but there are plenty of commercial boats tied up there, and I think they're still operating. Whenever I went I was tied up at the dock and walked in the back door, usually around 5am. They're just regular guys and seemed happy to help out with any kind of bait we wanted, they had tons of different species laying around. The Seabrook co-op would do the same I imagine.
Went over to Taylors today,they were closed must have gone to lunch.Sign said be back at 12:30.They open at 7am except Sunday.We had planned to fish today but wife said with storms coming and raining falling we made a bait run instead.Ended up at the Seabrook Co-op,do you know how many herring you can get in a 5 gallon bucket,holy $@#t.She even got me to buy lunch at Markey's in Salisbury Ma. Shudda went fishn,weather was great down there. Got enough bait for the rest of this season,maybe even chum for ice fishing.