You May Be Killing Steelhead And Not Even Know It

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Photo by Louis Cahill

Photo by Louis Cahill

Steelheaders are generally pretty serious about catch-and-release, but it’s likely that many are mortally wounding fish without ever knowing it.

There are few species of fish as vulnerable as wild steelhead. These fish are beset on all sides by threats both natural and man-made. With their numbers dwindling, it’s safe to say, every steelhead counts. It’s vital that those of us who fish for them practice the best catch-and-release practices.

However, common landing practices can kill fish without the angler ever knowing. My buddy Andrew Bennett told me this story. Apparently, a team of biologists studying steelhead in British Columbia discovered this problem, quite by accident. These scientists were tagging steelhead with GPS trackers. They determined that the least intrusive way to capture the fish was, well, the same way we do it. With a fly rod. They landed the fish, tagged them with the GPS device and released them. When they went to their computer to track the fish’s progress they discovered something alarming.

Within two hours many of the fish they had tagged, and released in good health, were dead. They collected the fish and performed autopsies to determine what had gone wrong. In every case the cause of death was head trauma. It turns out that ‘steelhead’ is a misnomer. The fish’s head is, in fact, its most vulnerable spot.

When landing the fish the researchers had played them into shallow water where they would be easy to tail. As the fish came into the shallows they were on longer, fully submerged. Without the resistance of the water surrounding them, their powerful thrashing was able to generate momentum that is not possible underwater. The flopping fish simply hit their heads on a rock.

The fish appeared fine when released, but their injured brains began to swell and soon they were dead. It makes perfect sense if you think about it. Fish have evolved in an environment where hitting their head on anything with enough force to cause damage is almost impossible. Their brains lack the natural protection enjoyed by terrestrial species.

Luckily, this unfortunate outcome is easily avoided. The angler has a couple of good options. Landing fish by hand in knee deep water is a little tougher but much safer for the fish. You can grab the leader to control the fish long enough to tail it. After a fish or two it will feel very natural. When possible, it’s best to use a good catch-and-release net. This is safest for the fish and easiest for the angler. A net helps you seal the deal while the fish is still fresh and requires little reviving.

Always control your fish once he’s landed. Keep his gills wet and support his head in case he makes a sudden attempt to escape. Keeping him, dorsal fin up, will keep his range of motion side-to-side, making it harder for him to injure himself. When possible keep him in deeper water. Never beach a fish when landing him and never lay him on the bank for a photo. It’s just not worth it.

Wild steelhead are a precious resource. Those of us who come to the river looking for them must lead by example and do our best to to be good stewards of these remarkable fish. Their future is, literally in our hands.

Come fish with us in the Bahamas!

Louis Cahill
Gink & Gasoline
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69 thoughts on “You May Be Killing Steelhead And Not Even Know It

  1. That’s a great point Louis. I have an angling buddy that worked at a hatchery for a while and he made mention of how little protection salmonids have on the top of their heads. I think I remember him saying that you could literally scrape away the tissue with a butter knife to reveal the brain. I’m not sure how accurate that is, but I believed it. We all want that hero shot when we catch a great fish, but you gotta be conscious of their heads. Holding that fish over knee deep water keeps that fish’s head from hitting the bank when it flops from your hands. Practice safe handling!

  2. I wonder about that just about every time I see someone land steelhead (or salmon or anything) that way. Intuitively it’s always seemed like a terrible idea considering how big on catch-and-release the guys landing the fish usually are, so it’s great to see someone pointing out the issue, and based on research nonetheless!

    • Ditto! There is an argument on a local Steelhead Facebook page and I would love to reference this article. But, it will be quickly discredited because it doesn’t site the source. It just says apparently a team of biologists accidentally found this. I would love to read the study.

  3. Great to see science and research helping us learn more about “How we should do things’ in flyfishing. Important article!

  4. Great post Louis. Dec Hogan taught me some time ago that if you land a steelhead in knee + deep water, they tend to remain much more calm and easier to get a handle on than if you drag them into the shallows. I’ve done this ever since and always found it easiest, and consequently best for the fish.

  5. Great insight on a species I enjoy chasing. Thanks for the great information and tips on how to keep steelhead around to fight another day!

  6. Can you follow up with the results/data of the research, to paint a complete picture? What this is signaling is a sea-change in the way that all wild fish are handled, from technique to education, to minimums for establishing rules and regulations for pursuing wild fish, especially important in the PNW where ESA-listed fish are targeted among mandatory kill hatchery fish in many of our systems.

  7. That was a great read. We need to get this article to as many fisherman as possible. Proper fish handling is something we as fisherman can always do a better job at. I always look forward to reading your post’s, thanks for keeping us updated and educated. Mike Morin

  8. Wow, this makes a lot of sense but something I didn’t think about! While I wasn’t a fan of fish flopping in the past, this is something I will take into greater consideration in the future! Thanks Louis!

  9. Here’s a link to a very good video produced by the Atlantic Salmon Federation on live release of salmon including tailing and netting practices. It should apply to steelhead or any other fish released live:

  10. I had no idea, this is good info. Unfortunately I don’t fish for steelhead, but I imagine the same applies to trout as whole. I generally try to keep them in the net and in the water at all times anyhow.

    The next I eat a stocked trout I’m going to do a little exploratory surgery…;)

  11. So, these “field biologists” flyfished for steelhead, landed and installed GPS trackers, released the fish, and many of the fish died. Something is wrong here. This doesn’t gibe with any of the peer reviewed C&R impact studies (which there are multiple) nor with reality. Places like the Dean River would have dead steelhead floating all over if the field biologists findings were accurate.

    I’m all for careful handling of wild steelhead. But the variable here is “installed GPS tracking units in the fish” so maybe that’s where the cause of death should be attributed eh?

    • well said, it makes perfect sense, and obviously is a good practice regardless of the research that might have been done. But quoting without a source is skeptical. and Like Rob pointed out.. installing a GPS on a fish.. i’d like to see how that works. The image in my head is a little Morbid

  12. where is the references?
    who ,what and where. If this report is legitimate , then it brings a whole new set of questions to C&R .
    Rob are you a lodge owner?

    • Hey Guys, thanks for getting behind this article and sharing it. I think it’s an important topic. Thanks for helping to spread the word.

      Several folks have ask about the study. I actually did a fair bit of searching for the info but came up empty handed. I should have gotten some names and numbers. I think the issue is (and I should have made this more clear), head trauma was not the focus of the study. This was knowledge gleaned in the process of doing a different study. I don’t know that the head trauma data was ever written up. Regardless, this is what was conveyed to me and I believe the source. Sorry I can no offer previously published work.

      I should say, I am not a scientist. That said, my practical experience backs up what I’ve been told here. If anyone reading this knows of published findings, pleas leave a comment and share what you know. The important thing is that we get together on protecting these special fish for generations to come. Thanks!

      • Thanks Rob , had you marked another fellow.

        Louise, thanks for the clarification, We as anglers /conservationists, must be open minded when it comes to conservation of the habitat/Fish /sport, studies , many of them never see light of day other than on the desks they were targeted for.
        Therefore it is up to us, when seeing something that pertains to our sport and the fish we have inherited, to be ready to change our ways or ?? if what we read possibly contradicts what we knew and or re-educates us on what best practices (subjective?)we collectively should be following.

  13. I support the gentle handling of these fish. The use of CnR landing nets is the most helpful suggestion of all. We routinely land fish that would are nowhere near the point of being tailable. I don’t understand why the scientists participating in this whole process wouldn’t have implemented such measures? Also, when looking at mortality factors with CnR steelhead, I’d certainly take as much a look at lactic acid build up and exhaustion as I would head trauma.

    All that said, I do find this sort of article troubling in the sense that it appears to be scientific when it really is not. I’m not saying that CnR head trauma to steelhead doesn’t cause mortality at the rate that is claimed, I just hate to see information like this passed along as fact without having the actual data to go with it. I think we can all agree that steelhead bashing their heads into rocks is not a good thing.

  14. The GPS tags that I’ve seen are about the size of a 410 shell with antennae sticking out, and get stuffed down the throat near the gills.

    Sandy, I’m not a lodge owner.

    It’s very important to handle wild steelhead carefully. But the scenario painted above doesn’t correlate with any science I’ve read or personal real-world experience.

    It’s non-attributed so nothing more than wild hearsay.

  15. I’d like to stand by this “study” but really without any sources these are Fox Facts. I hope these BC Bios are extending their findings. Please follow up on this.

      • Louis,

        We know there wasn’t a study done on head trauma. We’ve all read your article (some of us a number of times now). However, the bi-product of the research was an assumption that Steelhead are susceptible to head trauma and that this can happen when they are beached.

        Its clear from the response that what people are bothered about is the insinuation that Anglers are injuring fish by beaching them. When evidence shows that they are a lot more robust than that.

        Yes we should all use nets and do everything you advise. But I strongly disagree with the evidence (however it was accidentally obtained by way of another survey) that a fish that bangs its head slightly upon landing/beaching is a dead fish!

        As a creature that lacks arms and legs, and has to test everything with its mouth and head, has to jump up falls/weirs head first I would suggest that its quite likely that the name Steelhead is pretty appropriate.

        Yes encourage the very best handling of fish possible at all times. Absolutely. but to put an article out there that emphasises some bi-product research and change our behaviour because of it is a little uncalled for in such a public forum.

      • I’m not aware of any study in B.C. where the fish were caught and released using GPS. Have a close look at the LGL study and you will see there were only 4 fish that possibly died following release. There were extremely high survival rates even to post spawn and kelt (76.3% over 1999 and 2000).

        I did re-read your article and it indicates there was a BC study where released steelhead died within 2 hours of release. That does not add up when compared to the data collected over 2 years in the LGL study, which also noted multiple re-captures (some as many as 4 times).

        The LGL study also noted all steelhead were caught using conventional drift fishing gear, and the majority were caught using bait (salmon roe). No fish were caught using fly, however I suspect the result/outcome would be similar.

        I do strongly agree that steelhead should be handled very carefully and handled in a way that protects them from trashing around on the rocks. Steelhead are actually fairly hardy fish, having captured steelhead brood stock for 11 seasons my experience is very few fish die after capture and transport. So I guess your article suggesting the opposite caught me by surprise.

        I would sure be interested in seeing that study your article referenced. It would be great if you could put me onto it please. Thanks, Pat

  16. A very interesting article. However, I find such research a little hard to believe given the journey Salmonoid’s make upstream each year. Salmon and Sea Trout (Sea Run Browns) in the UK push up our rivers in much the same way as Steelhead do the world over. As part of this process they leap up falls, weirs, man made and natural structures, through bolder strewn rapid waters, where many of their leaps are unsuccessful.

    There are many places (and I suspect in the U.S. too) where you could happily go and watch Salmon and Sea Trout attempting to jump falls, weirs and large rocky outcrops (at the right time of year). Its clear to any spectator that many of these fish don’t make it first jump. Its common to watch them jump into the obstacle they are trying to jump over, they often land on rocks and structure that they were trying to jump clear of, often from a significant height without the support of water. If the above research were true, local poachers would spend a hell of a lot of time in the tails of pools waiting for the numerous dead to wash downstream. Its simply not the case. The below video from Toronto illustrates my point perfectly. Watch how many Salmon bounce off the stonework.

  17. I’m afraid that what I wrote in this article, although clearly stated, has been widely misunderstood. I will try to clear it up for you. The scientist I mentioned were not doing a study of steelhead mortality. They were studying migration and discovered that they were accidentally killing fish. The knowledge they gleaned from this was secondary. To my knowledge, there was never a paper written on the subject of head trauma. (There should be.) I am sure that, had that been their intention, they would have gathered the information in a different way. For a scientific study there would need to be a control group an so forth. Again, this was not a scientific study. It was information observed by scientist working on a different study.

    I made some calls to see if I could track these fellows down. Apparently one of the gentlemen died in the last year. That’s about all I have found out. For what it’s worth, this occurred on the Dean River. I’m not sure who was behind the research.

    Are you familiar with the mathematical theorem of Jordan’s curve? Simply put, it’s the idea that any closed curve divides a plane into two spaces, the interior and the exterior. More simply put, there is an inside of a circle and an outside. Such an obvious truth that no one bothered to prove it until the 1900s. Once Jordan brought it up, mathematicians argued about it for the next hundred years. That’s what we’re doing here.

    Let me make a suggestion. If you are finding the idea that head trauma leads to fish mortality hard to swallow, try this simple scientific test. Go out to the river, find a big rock and bang your head on it as hard as you can, five or six times, then jump in the river. Please get back to me with the data.

    Don’t beach fish people!

    It’s that simple.

    • The mortality arguments can get pretty involved. I would chose to err on the safe side and never beach a fish. For thirty years I have been landing fish by wading deeper into the water. They settle down easier and I don’t have to carry a net.
      I always to the downstream side of my legs to block the current, grab the leader
      and then the tail. I wouldn’t insult the fish by taking a picture with me in it.

  18. Louis, i appreciate that you say there was no study done on the actual mortality. However, any study on tracking fish would include references to the fish that were lost in the process of tagging.

    While I think that this topic should be brought up more often, I do not believe in the ‘a friend of a friend told me about some researchers…’, as being an adequate source of information. I’d also find it exceedingly unlikely that fish that were destined to have GPS tags placed in them, would be tailed at the beach, rather then netted and moved into a holding tub for the procedure. Since you heard it from a ‘source’, you’d think that source would be quickly contacted to get you the study information, rather then having to spend time googling for the result.

    I’m glad that this is getting out to the masses, and more people are questioning their previous landing techniques (see the discussion on Speypages to see the evidence). I completely agree that fish should not ever touch the beach, and at the very least this post will make people reflect on their own landing habits.

  19. Regarding Steelhead: The Idaho Fish and Game department and their fishery leader on the Clearwater river have established a no kill period of time in the early part of the season– July, August, September. Those of us who fly fish generally use barbless hooks– in fact, it may be required but it never enforced. Gear anglers are allowed to fish in the no kill season also– no enforcement on gear that I am aware of. The claim by fishery managers is that there is very little mortality to the fish no matter the gear or the subsequent release techniques used. More than likely, this is a justification statement which allows all forms of angling during the no kill season. The impression that I get from IDFG fishery people is that the steelhead and probably the salmon are a hardy lot and it does not matter too much about gear or handling.

    Hero photos are nice to have as fishing prowness is demonstrated to whomever. I just have to believe that handling a fish is important to its longevity and vigor. Education of the fishing public is probably the only way to teach proper techniques. I find it interesting that in order to obtain a hunting license in Idaho that the participant completes a hunter training course. I am wondering if that same logic should be used to obtain a fishing license– a fishing training class of some kind that would include handling and releasing as well as ethical behavior.

    After working as a volunteer in the steelhead hatchery system on the Clearwater, I find it interesting that wild (native) fish are captured along with hatchery fish; placed in holding tanks; chemically made comotose; crowded into lifts that take the fish out of water and dump them on stainless slanted tables for sorting; measured by handling (out of water); run through a machine that finds and reads a previously inserted PIT tag, and then dumped into a slide chute out of water into an empty plastic bin where a staff member takes the fish and places is “carefully” in a delivery trucks’ holding tank for a trip back to the river. The claim is that there is no damage to the fish– all is well.

    Yes, we should all work to handle these beautiful creatures with care or not handle them at all— and that includes the so called scientists and fish managers who claim– all is well — handle them as you want.

  20. The value of this piece for educating all salmonid catch and release anglers, especially if you include the Atlantic Salmon video, is enormous. I applaud you for writing it, Louis. I am going to discuss this topic at our January TU meeting and show the YouTube video.

    With regard to the tempest created by the piece beyond the point you obviously made about beaching fish, constructive dialogue on important subject matter is always educational, regardless of your point of view. When it comes to these issues, hitting a nerve is more effective than remaining quiet just because someone may think your source citations may not be in order. Also, I remain impressed with the ardor and knowledge of your readers!

  21. Reading this I can not agree – sure this is super safe way of doing it. But these fish jump waterfalls bash on side of rocks and survive. If anything the stress of of the GPS being installed could have killed them as it freaked the fish out.

    Cool story, but these fish are stronger than we think.

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  24. I appreciate concern in the article as well as the follow-up comments. I have spent many days in dive gear over many decades watching salmon and steelhead launch themselves against concrete dam faces. They do this over and over again and sometimes over a period of days before laddering. A very few die in the process. For these “biologists” to have their steelhead die within two hours of a self-inflicted head bonk (underwater none the less) seems rather far fetched. Regardless, handle these guys with care, keep them in the water, and revive with patience. Thanks for the reminder.

  25. Why do you say the least intrusive way to land steelhead is with a fly rod? Is this because that’s what you use, or are you implying that spin or casting tackle is more intrusive? Just curious. Also, I fish some of the most productive steelhead water in eastern oregon. I handle 15 to 30 steelhead a day and to my knowledge not even one has died. I am extremely careful with the fish when landing and releasing as I hope most people are. I’ve even repeatedly caught the same fish in a day and in consecutive days. I guess I’m just saying that with proper care, steelhead are a little more rugged than this post implies. I do appreciate the concern and love you obviously have for steelhead so please don’t take my views the wrong way.

  26. this is what seems to be the crux or focus of the debate:

    “Within two hours many of the fish they had tagged, and released in good health, were dead. They collected the fish and performed autopsies to determine what had gone wrong”

    That paragraph , suggest that the “scientists ” did further studies to “determine” the cause/s of the mortalities.

    However ,when reading the article or re-reading the article ,depending on the view or expectation that you have been pre-wired with, i.e:. Title or pre-amble. you can read and surmise different issues.

    I happen to agree that miss-handling the fish is a crime, and to allow a catch , steelhead or otherwise to flop around on the beach , sandy, or cobbled or boulder beach is abhorrent. I NOW feel strongly that in no case should a fish be lifted from the water or allowed to contact the beach, unless the fish are destined for the plate, but that is a different issue.

    This article is great , it focuses our attention on what may be a simple part of the equation, one that is often neglected.

    seems sometime the messenger gets flogged 😉

  27. L, so in stating these deaths as facts from scientists, but then having no real facts to back them up, this is just crap. This is simply your opinion, that SH have craniums soft as an egg shell.

    You may think you are doing good with this kind of commentary, but when you use pseudoscience to make an unverifiable claim, you undermine any future “research” in the field. It is unfortunate.

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  29. Well I’m not in it for the sport I practice catch fillet and realese, and by reading this article just proves it’s more humane to eat em than to release em!

  30. I think you are referring to the LGL study on the Chilliwack River in B.C. That study was conducted to determine the impact of multiple recaptures on a heavily fished river as well as potential impacts on successful spawning on recreationally caught and released steelhead. The results conclusively determined there was no correlation between multiple recapture and mortality and spawning success. It also demonstrated there were zero post hook and release mortalities in a 2 year study.

    Here’s the report

  31. I’d like someone to direct me to information where ANYONE is using GPS devices to study steelhead. I’m not talking PIT tags, or radio transmitters, but GPS.

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  34. I don’t think you will find any study out there using gps. I believe the LGL study is the only one that is remotely close, and that was radio tagging. That study conclusively determined there was no connection between actual catch and release hook mortality and widely held urban myths on the subject. Its statistically a non-issue.

    To my knowledge BC has never used gps tagging – far too expensive and we live in poverty here when it comes to funding fisheries management. I only take issue with the article putting it out there that this was somehow connected with a scientific study of some sort, when in fact it is not correct. The article claims some wide connection to handling fish and post release mortality, as well as angling methodology. There is no empirical evidence to support any of those claims.

    BC has a long history of steelhead brood stock capture programs and all the catch data I’m aware of shows very low mortality rates. In some cases those fish are caught and transported down river attached to rafts and jet boats in capture tubes. In some cases because the hatchery truck is not available fish are also held in river for a day or more. Despite multiple handling these fish are remarkably resilient.

    So, not to flog the messenger as was suggested – I do strongly agree with the general premise of the article which is we should be careful to avoid having fish landed on beach rocks where they thrash around potentially causing harm. The article does nicely position an issue that few anglers consider in their excitement to land the fish.

  35. just to be clear, I’m not condoning or sudjesting that we flog Louis, just that on occasion, when the poo flies ,you might need to change the gear. 🙂

  36. Great article and comments! No more beaching steelies, period.

    But isn’t it strange how we vehemently express our concern for these fish, yet continually refuse to face up to the root of the problem? If we truly care for these fish, WHY ARE WE FORCING THEM INTO SUBMISSION FOR OUR GRATIFICATION?? We “concerned” fly anglers are long overdue for a bitch slapping from the rest of the world. The answer to this conundrum is simple, but addicts are addicts. In our heart of hearts we know the truth: If we aren’t hunting for food, we have no business putting hooks in the water.

    Hypocritically yours,


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  38. Great notice to us all. Further, my fishing companion is a PhD biologist for Fish and Wildlife and he’s always told me that lifting a large adult salmonoid fully out of the water by its tail can cause severe spine injuries. Same reasons. They are dangling by their spine and effectively weigh 8x their in – water weight. Tail a fish in the water- yes. Lift out without supporting horizontally-NO.

  39. This is a great article and give us allot of insight into why these fish perish at our hands even though we practice catch and release. Remember catch and release means alive! We practice this to propagate the species and to allow others to enjoy the same fish that we did. I think it was Hemingway that said “a fish is to precious a resource to only be caught once”. I am encouraging an educational video for the DSR web site to define the proper techniques of both playing and releasing these magnificent fish. You should be able to see a video like this within the next year on their web site.
    Happy fishing and let’s kep the Steelhead and other Salmonoids alive and well.
    Capt. Lou

  40. Good article and interesting debate about the study. And although the fish mortality was a side observation and not the focus of the study, I think it is a good reminder to handle steelhead carefully and keep them in the water as much as possible where they are safe.

    Washington state has a regulation that you cannot remove a steelhead, salmon or bull trout from the water unless you intend to reduce it to possetion. A clear message that handling those fish has a consequence from keeping them out of the water too long or trauma from mishandling.

    I am investigating getting a similar regulation in Idaho and called and talked to Washington Fish and Wildlife about the origins of the regulation. The fish biologist I talked to said he wasn’t surprised at the fish mortality observations in the BC GPS study and indicated they had similar observations from studies they had done. I will see if I can get more information from him.

  41. I contacted the WAFW biologist and he said the study he mentioned was an internal study on the release mortality on rainbow trout that was never published/released.

    Doing some research on fish mortality online I haven’t found much that addresses fish handling/dropping, but there is good literature to support that removing fish out of the water impacts their survival (see references below). A good reason in itself to make sure to leave the steelhead in the water–especially if it’s wild.

    Hooking Mortality by Anatomical Location and Its Use in Estimating Mortality of Spring Chinook Salmon Caught and Released in a River Sport Fishery

    We estimated the hooking mortality of spring Chinook salmon Oncorhynchus tshawytscha that were caught and released to determine whether selective fishing on hatchery Chinook salmon would reduce harvest mortality of wild fish in a sport fishery in the lower Willamette River, Oregon. Hooking mortality in the fishery was estimated from hooking mortality rates for each of five anatomical locations (jaw, 2.3%; tongue, 17.8%; eye, 0.0%; gills, 81.6%; and esophagus–stomach, 67.3%) and from the frequency of these anatomical locations in the sport fishery (jaw, 81.5%; tongue, 5.1%; eye, 0.4%; gills, 5.1%; and esophagus–stomach, 7.8%). Mortality rates by anatomical location were estimated from recaptures of 869 tagged fish that were experimentally angled and of 825 tagged controls that were trapped in a nearby fishway. Anatomical hook locations in the lower Willamette River sport fishery were determined with creel surveys. We estimated hooking mortality rates of 12.2% for wild Chinook salmon caught and released in the sport fishery and 3.2% for the entire run of wild Chinook salmon based on a mean encounter rate of 26%. Hook location was the primary factor affecting recapture of hooked fish, but fish length, gear type, bleeding, and the elapsed time to unhook fish were also significant factors. A selective sport fishery in the lower Willamette River can be used to reduce harvest mortality on runs of wild Chinook salmon while maintaining fishing opportunity on hatchery Chinook salmon. The effect of selective fisheries for Chinook salmon in other rivers would depend on the frequency distribution of anatomical hook locations and on river-specific encounter rates.

    Physiological Effects of Brief Air Exposure in Exhaustively Exercised Rainbow Trout (Oncorhynchus mykiss): Implications for “Catch and Release” Fisheries

    This study evaluated the immediate physiological response of wild rainbow trout to catch-and-release angling in the Alagnak River, southwest Alaska. Information was recorded on individual rainbow trout (n = 415) captured by angling including landing time and the time required to remove hooks (angling duration), the time to anesthetize fish in clove oil and withdraw blood, fish length and weight, and water temperature at capture locations. Plasma cortisol, glucose, ions (sodium, potassium, chloride), and lactate were analyzed to determine the effects of angling duration, fish size, body condition, and temperature. Levels of plasma ions did not change significantly during the observed physiological response and levels of plasma glucose were sometimes influenced by length (2000, 2001), body condition (2001), or temperature (2001). Levels of plasma cortisol and lactate in extended capture fish (angling duration greater than 2 min) were significantly higher than levels in rapid capture fish (angling duration less than 2 min). Rapid capture fish were significantly smaller than extended capture fish, reflecting that fish size influenced landing and handling times. Fish size was related to cortisol and lactate in 2002, which corresponded to the year when larger fish were captured and there were longer landing times. Body condition (i.e., weight/length regression residuals index), was significantly related to lactate in 2000 and 2001. Water temperatures were higher in 2001 (mean temperature ± S.E., 13 ± 2 °C) than in 2002 (10 ± 2 °C), and fish captured in 2001 had significantly higher cortisol and lactate concentrations than fish captured in 2002. The pattern of increase in plasma cortisol and lactate was due to the amount of time fish were angled, and the upper limit of the response was due to water temperature. The results of this study indicate the importance of minimizing the duration of angling in order to reduce the sublethal physiological disturbances in wild fish subjected to catch-and-release angling, particularly during warmer water temperatures. It is also important to note that factors such as fish size may influence both the duration of angling and subsequent physiological response.

    Physiological Effects of Brief Air Exposure in Exhaustively Exercised Rainbow Trout (Oncorhynchus mykiss): Implications for “Catch and Release” Fisheries


    Rainbow trout (Oncorhynchus mykiss) which were air exposed for 60 s after exhaustive exercise initially had a much larger extracellular acidosis than trout which were only exercised. In both groups, however, plasma pH returned to normal by 4 h. Blood lactate concentrations were also greater in the air-exposed fish and continued to increase throughout the experiment. During air exposure, there was retention of carbon dioxide in the blood, and oxygen tension (Po2) and hemoglobin:oxygen carriage (Hb:O2) both fell by over 80%. After 30 min of recovery, however, blood gases resembled those in fish which were only exercised. Finally, survival after 12 h was 10% in control fish and 88% in the exercised fish but fell to 62 and 28% in fish which were air exposed for 30 and 60 s, respectively, after exercise. These results indicate that thebrief period of air exposure which occurs in many “catch and release” fisheries is a significant additional stress which may ultimately influence whether a released fish survives.

  42. Angler stress is mentioned as impacting steelhead and salmon survival but I have found little addressing the subject. Some mentions of head trauma on migrating smolts impacting survival reinforces that their head is vulnerable. However, there continues to be good data related to air exposure impacting fish mortality. Here is an excerpt from a study that is a summary of fish mortality in recreational fishing titled “Do Catch-and-Release Guidelines from State and Provincial Fisheries Agencies in North America Conform to Scientifically Based Best Practices”

    “Air exposure was the most widely discussed catch-and release issue among agencies. It was found that 44 of 49 agencies provided advice on the subject. The most common recommendation (64%) was to keep the fish in the water at all times. This is consistent with studies showing that air exposure is extremely harmful in fish that have experienced physiological disturbances associated with angling (Ferguson and Tufts 1992; Cooke et al. 2001; Suski et al. 2004). Ferguson and Tufts (1992) found that when rainbow trout were exposed to air for either 30 or 60 seconds after exhaustive exercise, mortality increased from 38% to 72%, respectively.”

  43. Pingback: How to Handle Fish | Canadian River Angler

  44. Pingback: Landing Big Steelheads |

  45. I have worked in hatchery research for five years as a volunteer and have had a career in the sciences for 25 years. A fishes tail is meant as a propulsion system in very limited ranges of motion. It has operated millions of cycles before you reach down and grab it for a Facebook photo. Fish moving from salt to fresh water go through skeletal changes that make them stressed and fragile. Has your fishing buddy ever complained about a bad back? The next fisherman you see grab and tail a fish out of water, ask him if he’d feel the difference between his balls hanging down, or being hung by them.

  46. The Wild Steelhead Coalition helped fund this study.
    Consequences of catch-and-release angling on the physiology, behavior and survival of wild steelhead Oncorhynchus mykiss in the Bulkley River, British Columbia
    Here’s a link to the abstract, however it requires a subscription.
    Two highlights:
    Estimated survival within 3-days of capture was 95.5%.
    Estimated pre-spawn survival was 85%.

  47. A large strong fish, while reorganizing its bodily resources to withstand the extreme rigors of a spawning run, is suddenly interrupted by an angler forcing it to use those resources to fight for its life is usually condemned to die. Time out of water, clumsy handling of the fish, squeezing internal organs, etc. all speed up the process. Sure, it appears to have recovered and looks healthy while swimming away. But the fish is often dead within a 1/2 hour or less.Take the time to observe this process the next time you think you safely released your catch. No rocks or scientists required.

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