Investigations are under way after thousands of shellfish were found on Barmston beach near Bridlington.
Crabs and lobsters, most of which were dead, were found along the beach between Barmston and Fraisthorpe.
One person described the scene as "carnage", with puffins and fish among the dead.
Anthony Hurd, manager of the Living Seas Centre, in Flamborough, said: "Something similar happened at South Landing last week, although it was not to the scale as that at Barmston.
"We have even seen lobsters in rock pools – something that is not normally seen.
"I think it is down to the recent rough weather and the prolonged easterly wind, which has been pushing things on to the shore.
"I've never seen it happen here, but have known it to happen in other places."
People are advised not to eat dead shellfish washed up on beaches as it is impossible to say how long they have been dead for and they could pose a serious risk to health.
