BETHEL ISLAND, Calif. - For two decades now, Michael Birch has spent about 150 days a year bass fishing for sport and in big-money tournaments on the Sacramento-San Joaquin River Delta.
The 51-year-old Oakley man knows the murky, narrow passages and tight switchbacks so well he can instinctively maneuver his speed boat through miles and miles of waterways, relying only on GPS to avoid water hazards and shallow spots and locate key fishing holes.
Out on the water, with time on his hands, he’s studied the growth cycles of the Delta’s massive swaths of channel-choking vegetation, such as Brazilian waterweed, which can sprout several inches a day, and floating water hyacinth, which can double in size in just two weeks.
He’s also tuned in to the characteristic sounds and smells of the Delta, such as beavers slapping their flat tails on the water, and the smell of fragrant tules wafting through the morning air.
But over the last several months, Birch said the sound of those tail-slapping beavers has all but disappeared, and the Delta reeks of rotting wildlife, dead fish and powerful chemicals.
“It smells almost like an over-chlorinated swimming pool,’’ said Birch. “We’ve had guys whose eyes have watered up from the smell.”
Birch believes that what he and others are smelling are pesticides sprayed on the Delta by California State Parks Division of Boating and Waterways to combat out-of-control grasses and plants.
State officials say pesticide sprays and pellets containing fluridone are needed to control invasive plants and weeds that displace native plants and form dense mats of vegetation that create safety hazards for boaters while obstructing navigation channels, marinas and irrigation systems.
State officials say warmer weather during the drought years of 2015 and 2016 significantly increased infestation levels, leading to changes in their vegetation management program.
Charts provided by the state show a 50 percent hike in the amount of pellets used from 2014 to 2017 and a 66 percent increase in the amount of spray that was administered during the same time period.
What’s more, officials say they recently received approval to treat invasive plants over a wider range of dates, “which improves our ability to control invasion plants by treating them at the most effective times.”
Given that, state officials told KTVU in an email that “we have been using more herbicides in recent years than in the past; and treating more acreage in recent years versus the past.”
And anglers from Sandmound Slough in Bethel Island to Rock Slough near Knightsen to Horseshoe Bend in Brentwood and Latham Slough near Stockton claim that increase is directly responsible for the spike in dead beavers, fish, turtles, goats, ducks, muskrats, and otters since the spring.
“Carp, catfish, bass, blue gill, crappie, you see them dead every time you go out,” Birch said. “You can smell the dead wildlife before you see them.”
Anglers have taken dozens of photographs of the dead animals as well as scores of pictures of dead fish, many of which have gaping sores on their bodies.
They also came together this summer to form the Norcal Delta Anglers Coalition to share information about the die-off problem and work to learn more about how the chemicals and the pellets the state is using is impacting the Delta.
"This isn't just about a couple fishermen. This is about five thousand fishermen,’’ “You just haven't heard their voices yet,’’ said Andy Doudna, who heads the coalition. “And that's what the Delta Anglers Coalition is. We are the voice for them. We're hearing it left and right, every day.”
The pellets used by the state are called sonar with an active ingredient of fluridone, which keeps underwater plants from performing their normal processes. The sunlight then causes them to deteriorate and decompose, creating a lack of oxygen in the water.
Anglers say this process might be to blame for the die offs and also one of the reasons some areas of the Delta look like a green swamp.
“We’re looking at the grass and it looks like toxic sludge,” said Birch. “One of our problems is they’re killing the entire ecosystem.”
“If we kill the grass, we kill the bass,’’ Doudna said. “I mean we have no grass for the bait fish to hang into. We have no crawfish in the grass anymore. The bass are literally going to leave this area because they have no alternative choice -- it's survival."
Anglers say they aren’t the only ones who have concerns for the condition of the Delta.
"This is a concern of all of ours. It's not just the fishermen,’’ said Doudna. “It's the wakeboarder, it's the jet skier, it's the guy who wants to get in the water and ride his board, it's the paddle boarder that's soaking in this water. We don't have confirmed evidence of what the repercussions are from this product in the water.”
KTVU spoke to several boaters, jet skiers, and wakeboards to see if they share angler’s concerns about increased spraying leading to dead fish and wildlife. Some said they had seen the spraying but didn’t consider it a huge concern. Few said they had seen an increase in dead wildlife or fish.
Gloria Sandoval, a spokeswoman for California State Parks, said in an email that the Division of Boating and Waterways “adheres to strict guidelines from local, state and federal entities to ensure that the Delta is protected from our use of herbicides.”
State parks officials told KTVU they have “heard of dead wildlife” but crews have not seen evidence of dead wildlife. And officials say there is nothing to suggest a connection between die off reports and the use of herbicides. KTVU provided pictures of the dead fish and wildlife to state officials, but did not receive a response.
State fish and wildlife officials were also emailed copies of the photographs, but did not comment.
“We don’t have any kind of widespread reports or records of die-offs,’’ said California Department of Fish and Wildlife spokesman Peter Tira.
State parks stands behind its controlled use of chemicals that it says are reviewed and approved by the U.S. Fish and Wildlife Service and National Marine Fisheries Service.
But KTVU decided to have samples of water independently tested to see what turned up. The state puts out weekly maps that show where the chemicals are sprayed and where the pellets are dropped.
But on the week KTVU was preparing to test, the maps showed spraying was being done all over the Delta. But maps showed specific spots for pellet dropping and a boat crew was found dropping the fluridone pellets in a Bethel Island slough.
Water samples were sent to North Coast Laboratories in Northern California and about three weeks later the test results came back showing “typical concentrations of fluridone found in the environment during the application season,” said Marie Stillway, the manager of the Aquatic Health Program Laboratory at UC Davis, who analyzed the results for KTVU.
“Those results are very indicative of the concentrations that you would expect in the water during the treatment,’’ said Stillway, who has studied the effects of chemicals like fluridone. “At those concentrations, those are too low to cause the kind of effects you're seeing."
Asked what could be causing the fish and wildlife to die, Stillway said it could be a combination of factors.
"That's a complicated issue and it's something that we as researchers are trying to investigate further,’’ she said. “There's a lot that goes on beneath the surface and so I don't have a definitive answer. But it has a lot to do with the combination of chemicals in the water and changes in things like temperature and salinity… when you have all of those factors, it's hard to pin it down to one specific thing."