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Striped Bass Feminization in the Delta

Marty originally published this on Dan Blanton's Bulletin Board but I found the subject so provocative I asked if CSPA could post it on our website. Marty generously agreed.

Large amounts of delta water are consumed by Californians living in both the Bay Area and Southern California. No effort is made to remove the chemicals that currently cause the sex shift of delta fishes. Could these same chemicals be causing fertility and other health problems for humans drinking this same water? Ed.

Following the post, Marty Gingras, DFG, published a response. His post is following Marty's article.

by Marty Seldon, NCCFFF
December 16, 2008 -- In the 1920’s our significant western population of striped bass had about a 50 percent ratio of females to males. Today, males represent only about 10% of the much, much smaller population.  UC Riverside concluded that we are now learning that there is a world-wide epidemic of fish feminizing activity. Present indications are that steroidal estrogens, pesticides, and insecticides such as the pyrethroids may be part of the problem that can result in reduced sperm counts and reproductive abnormalities.  In some cases, such chemicals have been found to disrupt neurological and immunological functions. Urban drain waters have also been found to be generally toxic.

The telltale marker vitellogenin has been found in open-sea and deep water fish. The feminization of flatfish off the Southern California Coast has been documented. One British study found estrogens in fish resident below waste water treatment plants. A Canadian study added a minute amount of the ethinyl estradiol steroid to a lake and the fathead minnows were destroyed. UC Berkeley scientists found 16 sites in the Sacramento-San Joaquin watersheds that have the potential for salmonid feminization.

The Cal-Fed sponsored “Estuary Magazine” summarizes some of these problems Http://www.sfestuary.org/estuarynewsletter.html (The article is in the December issue, not on-line as of yet.) They are serious.


As W.C. Fields said, “you are what you drink,” and parts per million of all sorts of horrible drugs are being dumped into our waterways and through our insufficient waste water treatment plants.  Man is next up on the food chain and anyone who kills and eats California stripers over 26” should have his head examined.  Also very frightening is that its also impacting our salmon and steelhead.



Posted by Marty Gingras on Dan Blanton's Bulletin Board, 2008-12-16, 14:35:53 in reply to Striped Bass Feminization posted by Marty Seldon on 2008-12-15 23:53:25

Hi all,

According to our creel and population (e.g., tagging) data colected almonst annually since 1969, the sex ratio of striped bass in anadromous waters of California is not skewed heavily (perhaps at all) towards females. If you know of data to the contrary, please contact me.

We are actively interested in striped bass sex ratio. Sex ratio is pretty hard to get at because of sampling bias, so we are now thinking of using genetics to determine sex of young striped bass.


Marty Gingras
Supervising Biologist (Fisheries)
California Department of Fish and Game
Bay Delta Region
4001 North Wilson Way
Stockton, California 95205

Phone (209) 948-3702
FAX (209) 946-6355
email mgingras@dfg.ca.gov

12-20-08 -- Marty reported the following: 

The December Issue of Estuary Newsletter is devoted to Estrogens,


Pesticides, and other important Delta Problems. 

On Page 2, “Pelagic Organism Decline (POD)” Dept of Water Resources Biologist Ted Sommer states: Sex Ratios have shifted from 50-50 in the 1920’s to only 10% females today (I had a typo and reversed it to 10% males but this may be worse), a signal that something rally big has changed out there.”  He also states, ”What’s been driving us nuts, is how you can have so many adults and so few juveniles.”


However I'm not sure that the original author didn't make a typo. In all of the cases I've seen, feminization occurs with the birth control and other drugs in the water column. Ed.


Marty provided this series of articles on the subject. Worth reading! Ed.


Estrogen in Our Rivers and Fishery Problem Reference