can you pick seashells here

Yes

I have lived there 45 and spend most of it at shired picking them up and never had anything said to me about it

We did it all the time, there's no signs saying not to.

Are you asking about legality or availability? There are a ton of shells here; whole low-tide islands made of oysters. I think I even found some sand dollars. However, I'm unsure if there are laws about removing and transporting them. I don't imagine that it would be a problem but always best to double check the local laws.