Enhanced Delta Smelt Monitoring still showing signs of smelt

Wednesday, 12/06/2017, 6:00 am
Staff

Less than a year ago, during the Obama administration, Congress enacted the Water Infrastructure for Improvements to the Nation (WIIN) Act around the same time as the Enhanced Delta Smelt Monitoring (EDSM) program was founded. The state was thinking on the same plane as the federal government, as one of the many mandates of the WIIN Act requires the Department of Interior to establish increased monitoring and distribution studies of Delta smelt.

The focus of the EDSM program is to record and determine the abundance, or lack thereof, of Delta smelt in eight locations in the Delta. Project objectives include estimating the number of Delta smelt at risk of entrainment and developing ways to provide early warning. Ken Newman, 2017 Long-Term Operations Biological Opinions Science Review meeting, Sacramento

The program ran from December 15, 2016 to November 24 of this year and was broken up into three phases. Phase one went from December through March and focused on adult Delta smelt. Phase two then continued from April through June, concentrating on post-larval smelt. Finally, phase three picked up from July through November, focusing on juvenile and sub-adult populations.

Crews set out once a week for four or five days and trawled in waters ranging from two to ten meters deep, sampling at least twice unless a predetermined amount of Delta smelt were caught in the first sample. The most recent samples taken the last week, ending phase three, found a total of three Delta smelt in one of the 25 sites surveyed, the Suisun Marsh. That followed finding only one the week prior in the lower Sacramento River.

The Delta Stewardship Council held a long-term operations biological opinion science review yesterday in West Sacramento where Ken Newman, a mathematician and statistician with the U.S. Fish and Wildlife Service (USFWS), presented the EDSM program to an independent review panel seeking unbiased feedback. This biennial science review is intended to examine last year's water operations and actions of several agencies set by their particular Reasonable and Prudent Alternatives, looking at the best available science to make informed decisions on an appropriate future trajectory.

A concern with the program is that Delta smelt are becoming increasingly sparse and such a small amount are being found, despite the intense effort to find them. The program has taken some criticism about the study area being too small and excluding nearshore areas. Waters that are less than two meters deep make up about six percent of the suitable habitats where Delta smelt may reside in the Bay-Delta region. 2017 Long-Term Operations Biological Opinions Science Review meeting, Sacramento

Dr. Brian Kennedy from the science panel asked Newman, “If you are forced to defend your decision not to sample areas less than two meters, what's the best answer for that?”

“That's a big open question, what's the density of fish in that six percent?...If they're really dense there, that small amount could matter,” Newman said.

A weekly report is released every Friday on the USFWS website with information about which sites have Delta smelt findings, including graphs and maps. There is a lot of attention on monitoring lately and it seems to be a common trend among agencies. Continued monitoring of the nearly extinct Delta smelt is crucial to understanding our ecological impact in the Delta, and the program could start inspecting the more shallow waters in 2018.