“Knowing the effect on the fish is more informative than knowing which chemicals may be causing it,” says UC Davis’ Richard Connon (whose colleagues gave him his sinister title), referring to taking an ecological rather than regulatory perspective on fish health, and also to the less obvious sublethal effects of contaminants on fish behavior and reproduction. Connon is the lead author of a wide-ranging journal article in the December 2019 issue of SFEWS on how to better focus contaminants research in the Delta, and how to use more advanced tools to get at the synergistic and additive effects of multiple contaminants and stressors. Despite decades of monitoring, gigabytes of available data, and significant regulatory oversight, there remains “major uncertainty” on the extent of these effects, according to the article. The article also highlights the gap between assessment techniques currently used by regulators and the more advanced techniques now at the fingertips of forward-thinking scientists.
 
The article describes an array of advanced analytical tools for getting at the complexities. These include “high-throughput screening” and “rapid throughput bioassays,” which can speed up costly and time-consuming testing of both water samples and biological effects. Some of the tools detailed go by names unfathomable to the non-scientist (in-silico analyses, Omic approaches, bioinformatics, eDNA metabarcoding…). Taken together, however, the 22 pages compiled from 27 co-authors clearly point to the synthesis and dedication required ahead to make useful recommendations to Delta managers. “Contaminants are always going to end up in waterways, but if we know which locations are having the worst effects, maybe we focus our efforts there, and also provide organisms with respites and refuges so they can better cope with all these stressors,” says Connon. “… like putting a fish in a spa or on a treadmill so they can build up their fitness.”

Pearls in the ocean of information that our reporters didn’t want you to miss
Cache Slough water quality monitoring station. Courtesy USGS
 

A recent test found more than 250 chemicals in the Delta’s Cache Slough, but "Dr Doom" says figuring out what they all are, and their concentrations, is beside the point in our efforts to understand stressors on native fish resilience.

“Knowing the effect on the fish is more informative than knowing which chemicals may be causing it,” says UC Davis’ Richard Connon (whose colleagues gave him his sinister title), referring to taking an ecological rather than regulatory perspective on fish health, and also to the less obvious sublethal effects of contaminants on fish behavior and reproduction. Connon is the lead author of a wide-ranging journal article in the December 2019 issue of SFEWS on how to better focus contaminants research in the Delta, and how to use more advanced tools to get at the synergistic and additive effects of multiple contaminants and stressors. Despite decades of monitoring, gigabytes of available data, and significant regulatory oversight, there remains “major uncertainty” on the extent of these effects, according to the article. The article also highlights the gap between assessment techniques currently used by regulators and the more advanced techniques now at the fingertips of forward-thinking scientists.
 
The article describes an array of advanced analytical tools for getting at the complexities. These include “high-throughput screening” and “rapid throughput bioassays,” which can speed up costly and time-consuming testing of both water samples and biological effects. Some of the tools detailed go by names unfathomable to the non-scientist (in-silico analyses, Omic approaches, bioinformatics, eDNA metabarcoding…). Taken together, however, the 22 pages compiled from 27 co-authors clearly point to the synthesis and dedication required ahead to make useful recommendations to Delta managers. “Contaminants are always going to end up in waterways, but if we know which locations are having the worst effects, maybe we focus our efforts there, and also provide organisms with respites and refuges so they can better cope with all these stressors,” says Connon. “… like putting a fish in a spa or on a treadmill so they can build up their fitness.”

About the author

Ariel Rubissow Okamoto is both today’s editor-in-chief and the founding editor of ESTUARY magazine (1992-2001). She enjoys writing in-depth, silo-crossing stories about water, restoration, and science. She’s a co-author of a Natural History of San Francisco Bay (UC Press 2011), frequent contributor of climate change stories to Bay Nature magazine, and occasional essayist for publications like the San Francisco Chronicle (see her Portfolio here). In other lives, she has been a vintner, soccer mom, and waitress. She lives in San Francisco close to the Bay with her architect husband Paul Okamoto.

Related Posts

Of Mice and Marshes: Surveying Salties to Save Them

It’s five in the morning, and Don Edwards San Francisco Bay National Wildlife Refuge remains in the tight velvet grip of night. All is peaceful and quiet, despite the fact that the toll plaza of the Dumbarton Bridge is less than a quarter-mile away. By 5:15, car dome lights and...

California will spend big bucks on beavers to try to boost their numbers and reap some of the benefits—including slowing wildfire—these ecosystem engineers can provide.

After years of advocacy by beaver “believers,” the state has allocated funding for a beaver restoration program. The $1.67 million in license plate funds for fiscal year 2022-23 and $1.44 million the following year represents a new way of thinking about beaver management in California, says Kate Lundquist, of the...

Climate change is heating, salinizing, and expanding the San Francisco Estuary, a review of nearly 200 scientific studies concludes.

Sea level rise, changing snow and rainfall patterns, and warmer waters are some of the changes already observed in the Estuary and expected to continue through the rest of the century as greenhouse gas concentrations rise. Changes to water are at the heart of the documented and further expected impacts;...