The silver trout (Salvelinus agassizii) is an extinct char species or subspecies that inhabited a few waters in New Hampshire in the United States prior to 1939, when a biological survey conducted on the Connecticut watershed by the New Hampshire Fish and Game Department found none.
Description
The silver trout was about a foot long. It had an olive-green back that faded to a bright silver underside tinged with vermillion. Females had faint golden spots along their side. Males were darker-colored with more red on the belly, and had small red spots within their golden spots. Size-based sexual dimorphism was also far more pronounced among the silver trout than among other char, with males being much larger than females, as opposed to only a slight size difference in other char species.
Taxonomy
left|thumb|1902 illustration by Frank Mackie Johnson
The distinctiveness of the silver trout was noted by famed naturalist Louis Agassiz as far back as 1859, who requested specimens of trout from Dublin Pond, and upon analyzing them, identified them as a taxon distinct from the brook trout.
Distribution
The silver trout was an exceedingly rare fish, having become trapped by changed drainage systems in two New Hampshire lakes (Dublin/Monadnock Pond and Christine Lake in Stark) that were left as successors of Lake Hitchcock, a very large glacial lake that persisted for 4,000 years where the silver trout probably evolved from brook trout.
In Kendall's 1914 monograph, an 1884 letter from a local fish warden is reproduced. The warden states that both silver and brook trout were captured from Dublin Pond for a project to stock nearby Stone Pond.
The silver trout was apparently one of only two native gamefish species that originally inhabited Dublin Pond prior to the introduction of other fish species. The other was a "perch" of uncertain affinities that inhabited an entirely different reach of the pond. The silver trout and the perch were never seen or caught together.
While the silver trout is most likely extinct, success stories like the Pyramid Lake Lahontan cutthroat trout and the Sunapee golden trout exist, and it may still persist.