Sulfite Cures Kill Juvenile Salmonids, ODFW Researchers Find

Breaking news–ODFW researchers today released findings showing up to 30% mortality in juvenile salmonids that ingested sulfite cured roe. The study shows that some fish die from eating just one egg, but that others survive up to 23 days before dying. Sodium sulfite, the most popular “bite stimulant” in modern salmon cures, was clearly identified as the culprit. Early reports from the study had shown much higher mortality in rainbow trout–up to 60% from ingestion–but the final report tempers those findings.

For those who market sulfite cures, this should come as no surprise. Sodium sulfite, and its relatives sodium bisulfite and sodium metabisulfite, are all linked to cancer in laboratory animals and humans, while not officially recognized as carcinogens by the National Cancer Institute. Those who cure eggs commercially, and those who have regular contact with cures and cured eggs, know the caustic effects first hand. Eyes and lungs burn, noses bleed, and skin becomes irritated. Some people report the development of allergies after repeated exposure.

Jeff Mishler, a long time advocate for wild salmonids, instigated the study in 2008 after becoming concerned about the potential harm sulfite cures might be having on baby salmon and steelhead.

“I had heard stories of trout dying from eating cured eggs,” says Mishler. “Then one day while I was bobber fishing with my Dad, I noticed swarms of young-of-the-year steelhead pecking at our baits. Then we noticed the shoreline. Bait anglers had disposed of their old bait along the beach, creating a fuzzy pink margin along the river bank. Baby steelhead were eating them like crazy, and cutthroat hung behind waiting for an easy meal. It suddenly occurred to me that the poisons in cured eggs could be having serious impacts.”

Over the year that followed, Jeff saw this scene repeated everywhere he went. Finally, his concern demanded action, and he worked with ODFW’s research team to craft a study.

Now that this study has been released, anglers and the sportfishing industry are unsure what will happen next. Advocates for wild steelhead and salmon will work hard to spread the word, and push for a ban on sulfite cures. Debate is likely to flare, and more study will undoubtedly be call for to prolong any action.

“The smart manufacturers will simply design new cures that are not poisonous to our fish,” says Mishler. He adds, “Anglers want to do the right thing, and will undoubtedly move toward products that are safe for salmon.”

Ed Bowles, chief of fisheries at ODFW, was careful to clarify that the new study does not attempt to quantify the impact these poisonous bait cures have on fish populations. “We’re not interested in doing that research. It would be incredibly difficult and costly, and it’s not necessary,” Bowles said. “While this doesn’t appear to represent a crisis, we’ve found out that these cures present a non-targeted impact on our salmon and steelhead. Manufacturers need to adjust and get on with it.”–RR


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14 Responses to Sulfite Cures Kill Juvenile Salmonids, ODFW Researchers Find

  1. Rick Allen says:

    Wow! What a nightmare. How has this gone on for so many years? Something must be done. Please, everyone spread the word. Tell anyneone who will listen. Let’s take action!

  2. Karl Mueller says:

    Looks like it kills more than juveniles 😉
    Seriously though, it is really easy to cure roe without sodium sulfite as generations of anglers have. I’m prety sure they caught salmon prior to the 1980’s when this chemical came into widespread use. It’ll be interesting to see how this plays out and how the industry responds. I’ve already seen some spin and some obseqious fawning elsewhere on the web.

    Bottom line: using this stuff is discretionary, unnecessary and ingesting as little as one egg kills some smolts. I would speculate there are sublethal impacts as well. Sodium sulfite is uncalled for.

  3. Steve says:

    Today, (Thurs.) I took my lunch break and stopped in the new sporting goods store in Eugene. I actually spent alot of time looking a the cures for this reason.

    What surprised me is most don’t print the stuff that’s in them..


  4. Rob R says:

    Manufacturers are not required to list ingredients, but all commercial “cures” are sulfite-based. Some coloring agents are mistakenly used as cures, when they are only intended to add color. Coloring agents most often used today contain formadehyde (sp?) which is pure poison. They also include an array of other questionable products.

    A favorite quote I heard yesterday, while interviewing manufacturers, was this: “I was surprised that sulfite was the problem, when our cure has so many other nasty chemicals that I expected to be the problem.”

    The good news is that these same polluters appear to be willing to do the right thing. Time will tell…

  5. kent says:

    Anybody know if Borax cured eggs create a similar effect? I’ve used plain old 20 Mule Team Borax to cure eggs, mainly because I don’t like the dyes and mess of the commercial Cures.

  6. Rob R says:

    Here’s a letter I just sent to the ifish community:

    To stem any further speculation as to the origins of ODFW’s egg cure study, I want to share my side of the story and explain my perspective on this topic: One day several years ago I arrived at the Guide Shop to find Pete’s pet rainbows belly up in the fountain pool. I went inside and asked Toy what happened. She said she didn’t know, that they had been fine the day before. Pete was vacationing somewhere, and the girls were in charge of feeding the fish. The worm guy hadn’t been by the shop, and without the usual trout food, Liz and Toy had been feeding the trout cured eggs. I remember saying something like, “That would do it!” Toy was surprised by my reaction and asked why we would use bait that we knew was poisonous to fish. I was stumped. There was no proof at that time that sulfite cure was dangerous, but it seemed intuitive. Liz used to come out of the basement after a curing session crying from the chemicals, eyes burning, stained from head to toe, complaining that her nose and lungs were burning–obviously not bio-friendly stuff!

    A year or two later I was fishing the Trask side-by-side with Jeff Mishler. He was flyfishing and I was using every method in the book. Markee was giving us the usual shrill ration of grief, calling me a snagger, etc. At some point, as I reeled in a bait of eggs, I pointed out a swarm of young-of-the-year steelhead chasing the bait. I related the Guide Shop trout incident, and Mishler, being a man of action, got the idea for a study. Later, while fishing with his Dad on the Nestucca, Jeff’s idea for a study crystallized, and he soon started working toward that end. This week’s announcement from ODFW is the culmination of those efforts, and I applaud Jeff for working on behalf of our fish. It would be a mistake to assume that Jeff’s intentions are to attack bait fishermen. Jeff cures and fishes eggs himself, but he is also an ardent advocate for wild steelhead and salmon.

    Here’s where things get a little sticky: I consider Scott Amerman to be a friend and mentor. I owe a ton to Scott and Gary, two of the finest salmon fishermen I know. It’s never been my intention to harm their business. Far from it. I helped build their new website with an eye toward conveying the image that I believe they represent: the best of the best. And I won’t pose for holy pictures. I’ve soaked hundreds, if not thousands of pounds of Amerman eggs over the last 12 years, and I’ve recommended them to hundreds of anglers.

    You have all seen the professional manner in which Scott has approached ODFW’s research findings. And he’s 100% correct that there has been no documentation of smolts or parr dying in the wild from eating cured roe. Despite my concerns, and despite the solid results of ODFW’s study, there is no evidence that fish are dying from sulfite ingestion in our rivers. ODFW biologists think the effects of sulfite cures on fish populations are likely to be negligible. But the fact is we don’t know. I empathize with Scott’s concern, that taking sulfite out of his cure might not solve anything. There could be other chemicals in several of these cures that could be found to be harmful to fish, if further study were conducted. But given the information we have today, I think the prudent thing to do is stop using sodium sulfite and any other chemicals that we suspect to be harmful. To me it’s a matter of doing the right thing for the fish.

    Finally, I want to express my sincere gratitude to the vast majority you who are standing up for our fish, especially Bill Monroe. Thank you very much! You’ve given me a much needed dose of faith and hope.

    Happy Holidays, and best wishes for a great winter steelhead season!

  7. Jeff Mishler says:

    Nope. Studies have proved that borax does not kill juveniles. Salt and sugar cures are fine too. Jello. fine. There are plenty of options out there.

  8. Jeff Mishler says:

    I take that back about borax. Apparently there is a study that concludes there are physiological impacts on juveniles fed borax cured eggs, not mortality but developmental issues. ….More later.


  9. Steve P. says:

    Rob, where is that letter posted on ifish? Curious to read reaction to it.

  10. Rob R says:

    I don’t think the letter will ever get posted on ifish. Long story 🙂

  11. scott says:

    Maybe instead of spending enormous resources and time trying to save a few smolt, we should be worrying about all of the “run off contamination” that enters Puget Sound and Portland Metro waterways.

    According to published reports, every 2 years enough surface oil run off from city streets enters Puget Sound to equal the Exxon Valdez spill.

    This would seem to be a more pressing problem than a flawed “scientific study” that attempts to draw wide sweeping conclusions with very little, if any, fact to back it up.

    Oh ya…let’s not forget about you fly guys with all of your dubbing material, fly dry, feather dyes and other products that you so generously apply to and or use in and on your gear.

    However, I am sure that there is a reasonable explanation and justification for your “damage” to the resource.

  12. Karl Mueller says:


    Maybe we should worry about run-off contamination and using poison baits that appear to kill smolts. I don’t know how reducing run-off in Puget Sound and Portland would address coastal salmon smolts in Oregon.

    It seems to me everyone here is being fairly reasonable in their arguments with the exception of one person. I don’t even see anybody on this site foaming at the mouth or pointing a lot of fingers at bait fisherman. Why so defensive?

    Personally, I fly fish, I fish with hardware and very occaisonally I drift eggs. This isn’t about technique. If you notice, the fellow who instigated the study was fishing eggs at the time he became concerned.

    For me, if I am doing something entirely optional that kills smolts I will modify my behavior. If there is a study done that shows dyes in dubbing kills smolts, well then, maybe we will have to move to vegetable based dyes.

    You do make a valid point, we should all worry aout how our behaviors impact salmon, including you.

  13. Doug says:

    The cured egg issue has received a lot of attention, and the use of sulfites should probably be phased out if it’s shown to cause fish mortality of any significance, but you can also think about this as yet another “weapon” we have at our disposal to kill fish unintentionally.

    Isn’t it odd that there are several stocks of salmon and steelhead listed under the endangered species act, but ODF&W and the National Marine Fisheries Service still let us head out to the ocean, rivers and streams in pursuit of lowly hatchery fish, even though often times that means culling through a bunch of fish you can’t keep before you latch on to the one or two that you can keep? On average, 1 or 2 out of 10 salmon that are hooked and released will die from stress, injury or because of their weakened condition, more likely to be eaten by a seal or some other fish-eater. Bait fishing was mentioned in the article on cured eggs, and that method can have the highest death rate because fish usually swallow the bait and hook whether it’s eggs, shrimp or whatever. Fly fishing also has a higher hooking mortality rate than lures.

    None of what I’ve written is news to most serious fishermen, but before you head out to soak whatever it is you intend to catch a fish on, keep in mind that there’s a good chance you’ll kill a fish that you release. In the case of salmon and steelhead, odds are good that the fish will have spawned in the near future too, but at least they won’t be producing the small fish to be exposed to death from eating cured eggs!

    Isn’t it odd that we all find a way of justifying our actions when we know darn well we’re likely to commit a philosophical crime?

  14. Devon keiner says:

    Does anyone have the actual study for this? I’m a fisheries technician student and I am doing an experiment regarding the affects of cured baits on salmon smolts. this study would be really helpful to me.

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