This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Are we about to witness the extinction of the controversial delta smelt (Hypomesus transpacificus)? The most recent survey for the tiny fish, over which decades of battles over water rights have been fought, counted just four females and two males.
The announcement came just days after a NASA scientist warned that drought-stricken California only has one year of water left.
Delta smelt used be common throughout the Sacramento-San Joaquin estuary until its water was diverted to supply the 25 million people and farmers who live in the area. Invasive species and changes in water salinity and clarity also played a role in the smelt’s decline. They were protected under the Endangered Species Act in 1993 and a recovery plan was established in 1996. The average population between 2000 and 2006 was 353 fish. That population crashed to just 25 fish the following year. The species has never recovered.
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Despite this extremely low population, the delta smelt has never been listed as anything more severe than “threatened” on the endangered species list. Numerous petitions and lawsuits have tried to change that, to no avail.
Dozens of lawsuits have also tried to remove water usage restrictions put in place to protect the smelt. Most recently, the Supreme Court declined to hear a case where farmers sought to overturn some of those water restrictions.
Delta smelts have a one-year lifespan and a very low reproductive rate, so unless these six fish get pretty darn busy pretty darned quickly, the future does not look bright for the species.
Photo: Peter Johnson, U.S. Fish and Wildlife Service
