On Wednesday of this week, an interesting ruling was issued by the U.S. Fish and Wildlife Service regarding two species we have on display at the Tennessee Aquarium. The two species are the shovelnose and the pallid sturgeon (Scaphirhynchus platorynchus and S. albus respectively) and they are exhibited in the Reelfoot Lake tank in the Tennessee River Gallery. These very similar looking fish, both belonging to the same genus, are found in portions of the Mississippi and Missouri Rivers. Both species prefer similar big river habitat and can be found inhabiting the same stretches of river. The larger of the two species, the pallid sturgeon, has been listed as “Endangered” by the USFWS since 1990, receiving the highest level of protection. The smaller shovelnose sturgeon whose population is in much better shape, is not deemed to need protection- in fact, a commercial fishery exists in some states for the harvest of shovelnose sturgeon for their roe (eggs) used to make caviar. According to the recent ruling, however, shovelnose sturgeon will be listed as “Threatened” for the portions of their range that overlaps the range of the pallid sturgeon prohibiting all commercial fishing for this species for large parts of pallid sturgeon range. This ruling goes in to effect as of October of this year under a Similarity of Appearance clause in the Endangered Species Act (50 CFR 17.50).
Pallid and shovelnose sturgeon sometimes appear so similar that even trained scientists have difficulty distinguishing some members of each species from the other. There have been documented cases where commercial fishermen unknowingly harvested endangered pallid sturgeon. A small pallid sturgeon could easily be mistaken for a shovelnose, and a large shovelnose sturgeon could easily be mistaken for a pallid. Because of the difficulty in visually distinguishing the two species in the wild, federal regulators felt that it is necessary to prohibit take of both species in order to protect the critically endangered pallid sturgeon.