Fish, lobsters, crabs, whelks and even seals have been killed by a combination of freezing seas, gales and high tides during last week's freak weather, and deposited on beaches along the Holderness coastline.
Lobsters are the only species to have survived in large numbers, and Yorkshire Wildlife Trust volunteers are leading a rescue operation to return them to the water.
The charity described the piles of whelks, mussels, starfish and shellfish as 'ankle deep' on beaches near Bridlington. Their Living Seas action team are working with local fishermen to gather the lobsters and take them to special tanks for care until they can be released.
North Sea marine expert Bex Lynam explained what caused the mass stranding - an event that happens on average around once every 10 years.
“There was a three degree drop in sea temperature last week which will have caused animals to hunker down and reduce their activity levels. This makes them vulnerable to rough seas – they became dislodged by large waves and washed ashore when the rough weather kicked in. Larger animals such as dolphins are more mobile and can save themselves by swimming away when this sort of thing happens.
“Lobsters are one of the few species still alive – that’s why we’re saving them with local fisherman. This area is very important for shellfish and we work alongside fisherman to promote sustainable fisheries and protect reproductive stocks. It’s worth saving them so that they can be put back into the sea and continue to breed."
Holderness Inshore is already designated as a Marine Conservation Zone. The government is due to announce a consultation into more marine conservation zones this year.