Thousands of dead fish and sea creatures including seals and velvet crabs washed up on Yorkshire's East Coast over the weekend after gale force winds and an underwater storm.
A group of fishermen rescued live lobsters to release them back into the sea at Fraisthorpe, near Bridlington.
Yorkshire Wildlife Trust has described the scenes on Holderness Coast as 'devastating'.
Meanwhile in Lincolnshire, dozens of dead fish were found in River Witham near Woodhall Spa.
The Environmental Agency said it has experts on site.
We have a team of environmental experts on site, working hard to identify the cause of this incident. Our focus is on ensuring we understand the reason behind the deaths and ensuring it has stopped. At this stage, we believe the deaths are the result of pollution entering the watercourse, and not cold weather or salt from road gritting. If anyone spots signs of pollution or fish in distress, they can contact our Incident Hotline on 0800 80 70 60.