Conservation efforts along the 153 miles of the River Thames have delivered mixed results for wildlife, according to a new report that finds improvements in some species and habitats alongside emerging threats from climate change and pollution.

Researchers recorded increases in several wading bird species, marine mammals and restored natural habitats, including intertidal areas that act as nurseries for many fish. The river continues to support a surprising range of wildlife, with seahorses, eels, seals and even sharks – including tope, starry smoothhound and spurdog – now documented in the Thames.

However, the number of fish species found in the tidal stretch of the river has shown a slight decline since the early 1990s. Conservation scientists say more research is needed to understand the reasons behind the trend.