Salmon fishing
Archer was a key figure in early research into "the sex life of the salmon" and in efforts to protect it from commercial netting. He set up home in Norway, having secured the fishing rights to the Suldalslågen, a major salmon river in 1884.
It was salmon fishing that was the primary interest of Walter Archer when he came to Sand, Rogaland. He leased all rights to salmon fishing in the entire Suldalslågen watercourse for a period of 40 years, from 1884 to 1924. Salmon stairs were built in the Sandsfossen waterfall in Sand, a hatchery was started, salmon were marked as part of an extensive work to protect and strengthen the salmon stock. For the first time in hundreds of years, the fish could go undisturbed by anything other than sport fishing with rod and line on the entire stretch.
In 1892, Archer was appointed Chief Inspector of Salmon Fisheries in Scotland. He left Scotland in 1898 to take up the position of Inspector of Fisheries for England and Wales.
As Assistant Secretary, Archer was in charge of the Fisheries Division of the Board of Agriculture and Fisheries since its establishment in October 1903. He was a member of the Royal Commission on Salmon Fisheries, 1900–1902, the Committee on Ichthyological Research and in 1908, Archer became President of the International Council for the Exploration of the Sea, the world's oldest intergovernmental science organization.
On 3 May 1912, The Times reported that Archer had been compelled to "retire from the public service owing to ill-health".
