A health check on Ireland's native species has put six fish, including Atlantic salmon, on a new extinction alert.
The threatened wildlife red list warns the European eel is at critical levels while the rare natterjack toad, the only amphibian of its kind in the country and a protected animal, is endangered.
While most fish stocks were reported to be in good health, five species were regarded as vulnerable.
Experts who compiled the study for the National Parks and Wildlife Service blamed water pollution, the spread of invasive species, overfishing, unsympathetic river management and climate change for the red list.
Habitat loss is the main reason for the natterjack toad's new classification.
Dr Cathal Gallagher, of Inland Fisheries Ireland, said the red list would be used to decide how threatened species could be protected over the next decade.
"For us who work closely with fish, this document catalogues the status, distribution and threats facing both our native and non-native fish species, it points to outstanding issues that need to be addressed and gives us a time frame for actions," he said.
"This document provides scientists, managers and stakeholders with an analysis which can be used to support our fish populations for the next 10 years."
Scientists involved in the red list study hit out at river barriers such as weirs for their impact on migration.
The fish populations said to be vulnerable were pollan, Arctic char, twaite shad, Killarney shad and the Atlantic salmon. The lamprey was classified near-threatened.