January 15, 2021

2021: Is this the year that wild delta smelt become extinct?

[Cross-posted from California WaterBlog]


By Karrigan Börk, Peter Moyle, John Durand, T-C Hung, and Andrew L. Rypel


2020 was a bad year for delta smelt. No smelt were found in the standard fish sampling programs (fall midwater trawl, summer townet survey). Surveys designed specifically to catch smelt (Spring Kodiak Trawl, Enhanced Delta Smelt Monitoring Program) caught just two of them despite many long hours of sampling. The program to net adult delta smelt for captive brood stock caught just one smelt in over 151 tries. All signs point to the Delta smelt as disappearing from the wild this year, or, perhaps, 2022.

In case you had forgotten, the Delta smelt is an attractive, translucent little fish that eats plankton, has a one-year life cycle, and smells like cucumbers. It was listed as a threatened species in 1993 and has continued to decline since then. Former President Trump made it notorious when he called it a “certain little tiny fish” that was costing farmers millions of gallons of water (not true, of course).

 

As part of the permitting process for Delta water infrastructure, the USFWS issued a Biological Opinion (BO), written by biologists, that found that increased export of water from the big pumps of the State Water Project and the Central Valley Project would further endanger the smelt. The BO was then revised by non-biologists to conclude that increased pumping would not hurt the smelt. The reason given was that large-scale habitat improvement efforts, plus the development of a facility for spawning and rearing of domesticated smelt, would save the species. We have written a short, fairly readable, article for a law journal that describes why the revised BO will not save the smelt. We will not write further about the paper in this blog but encourage readers to give the full article a read (it is a free download).

 

So, is this the year the smelt becomes extinct in the wild? Frankly, we are impressed by its resilience (see previous California WaterBlogs on smelt status) but small populations of endangered pelagic fish in large habitats tend to disappear, no matter what we do, partly the result of random events.

Looking for delta smelt

We trawl clear Delta water

And find emptiness.