Great predators in Britain's seas, like basking sharks, dolphins and porpoises, urgently need more protection, according to a new report.
The Wildlife Trusts say the animals are at risk from over-fishing, pollution and boat traffic.
They're calling on the government to create 17 protected zones around the coastlines in England and Wales.
The government says it's working to support the creatures but isn't sure protected zones are the best solution.
The Wildlife Trusts say that potential protected zones will work because the areas would be kept free from intensive boat use, wind farms and a type of fishing called scallop dredging. That would mean the water would have more nutrients in it, which is better for sea life and be better quality in general.
Experts say the nutrients would would feed plankton, which attracts fish and whales as it's one of their major food sources.