Experts claim that the capture of a seahorse in the Thames estuary is a sign that the river is getting cleaner and warmer.
According to the BBC, the seahorse was caught by fishermen off Leigh on Sea, Essex, and the species hasn't been caught in the Thames since the 1970s.
David Knapp of the Sealife Centre at Southend, who are keeping the seahorse, told the BBC: "Everyone thinks the Thames Estuary is a polluted, dead river but that could not be further from the truth.
"We have seen an increase in all sorts of wildlife, not just fish but birds too.
"Little egrets and avocets which were very rarely seen in England a decade ago are now quite a common sight along parts of the Thames."