A question I get asked on occasion is: Why all this fuss about endangered delta smelt when there is another smelt that looks just the same that can takes its place? The smelt being referenced is the wakasagi (Hypomesus nipponensis), which is indeed similar to the delta smelt (Hypomesus transpacificus). In fact, both species were once thought to be a single species (H. olidus), the pond smelt, with populations scattered along the Pacific Rim, from California to Japan. In 1963, Don McAllister, a Canadian ichthyologist and smelt expert, examined all populations and concluded that the populations in Japan and California were different from the intervening populations. But he also concluded that the two comprised just one species, with the scientific name noting their trans-Pacific distribution. Because having one freshwater species in two locations separated by thousands of miles made no sense from an evolutionary perspective, the species was later split into two species. This left the delta smelt stranded with the transpacificus epithet, following standard rules of zoological nomenclature.
The natural separation of the two species was broken by biologists from the California Department of Fish and Game (CDFG) in 1959. CDFG thought the pond smelt, then recognized as just one widespread species, would be the perfect forage fish for trout and salmon if planted in cold-water reservoirs.
Full Story: https://californiawaterblog.com/2021/02 ... lta-smelt/
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