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Saturday, April 18, 2015

Should we Minimize the Angling Duration to Maximize the Survival Rate of Released Fish? What Exactly Happens after you Fight and Release a Fish?

Hello, Blog Readers!

A couple years ago I decided to write a technical fishing post on fish hibernation, since many people sent me e-mails and asked me questions about whether fish hibernated or not. After hours and hours of research and writing, I created a well balanced post with plenty of empirical evidence. Today we will be doing something very similar to that! 

--- Introduction ---

Over the years, I've received much criticism from readers and fellow anglers about "how to properly play a fish." Scientifically speaking, those people were concerned about my "angling duration" and its consequences to released fish. By definition, the angling duration would be the amount of time that it takes to play the fish and reel it in. I would assume that people watched my YouTube videos and read about my fishing preferences (i.e. lighter tackle for bigger fish), eventually starting to get worried about the fish's safety after release. 

The fact is that a huge part of the angling community nowadays practices what is know as C&R or CPR: "Catch & Release; Catch-Photo-Release." That is certainly a wonderful thing! As the famous fly fisherman Lee Wulff mentioned one day: "The finest gift you can give to any fisherman is to put a good fish back, and who knows if the fish that you caught isn't someone else's gift to you?" Indeed! If we want to maintain good fishing for future generations, catch and release is certainly the way to go. So...we go outdoors, catch our fish, take photos, put them back in the water, and we go home proud of ourselves for doing so. We are referred to as a breed of "Catch and Release Anglers." Everything sounds perfectly fine, doesn't it? However, let's think about the fish for a moment: what exactly happens to that fish after it is released? Is it really going to heal from its experience and survive, so it can be caught again according to Lee Wulff's words?

My obvious answer would be "I hope so," and truth be told: in most cases we won't know because we will not be able to see what happens to it after its release. As catch and release anglers, we can only hope that the fish will live and survive to tell its tale. Because we have no certainties when it comes to its fate, we have adopted "trends" in order to maximize the fish's chances of survival. Those trends include the basics of safe fish handling and proper CPR, such as wetting your hands before touching the fish; exposing the fish to air for as little as possible; restricting the fish from bouncing over rough structure; using barbless hooks to avoid extreme injuries; etc. It would certainly be a shame if our released fishes died because we failed to comply with those trends! If that happened all the time, we would have become hypocrites in disguise and the meaning of Catch-Photo-Release would be worthless.

Anyways...It so happens that angling duration is also a dependent variable when it comes to the released fish's survival. Therefore, the question that we will be analyzing is a very different and interesting one: should we force-play our catches and fight them for as little as possible, so their chances of surviving after release are higher? Keep that question in mind as you read through this post. :)

Fighting a fish is certainly a joy for every angler! Every second of it is pure adrenaline! However, how much does each one of those seconds damage the fish afterwards? After we release them, will they really recover from the fight and live to be caught another day? Photo Credit: Bryan Karl Lathrop Photography.

--- Contents ---

This post will be divided in the following sections:

--- The Proper Ways of Catch-and-Release ---
--- Fish Anatomy and Physiology: What Happens during the fight? ---
--- Fish Anatomy and Physiology: What Happens after the release? ---
--- To Play or not to Play the Fish ---
--- Conclusion ---

Note: You may jump to certain section anytime by use of the search engine: press Ctrl+F and type the whole line in the search tab.

--- The Proper Ways of Catch-And-Release ---

As mentioned previously, C&R is not as simple as it may sound! Simply catching a fish and putting it back without any sort of consideration for its afterward health is not proper C&R. Never forget, anglers: the main objective of practicing C&R is to ensure the fish's safety after release. There is no point in practicing it if the fish dies a couple hours later. Without fish, there is no fishing. Period. 

According to the Ichthyology literature, there are five "general trends" to preserve fish populations in our waters: (A) reel the fish in as fast as possible to prevent exhaustion and lactic acid build up in fish; (B) leave the fish outside of the water for as little as possible to prevent anoxia; (C) avoid targeting specific sensitive/soft Species (i.e. Walleye, Trout, Salmon, etc) during high water temperature levels to minimize mortality; (D) use barbless hooks and lures to avoid extreme tissue damage and bleeding in fish; and (E) avoid targeting fish during their respective spawning seasons to preserve its future populations. 

I'll be very sincere with you folks: from these 5 trends, I follow 4 of them religiously (as for 04/18/15). The only one that I don't yet follow is (D), and that is about to change -- I just ordered a nice batch of barbless hooks from Gamakatsu and I'll test them to see how it goes. The problem with barbless hooks nowadays is that it's hard to find a good brand/supplier with high quality and low prices...hopefully this will change as time passes.

Regarding (A), this is the main topic for this post and I'll make sure to include my point of view at the end of it. However, just so everyone knows, I don't power-play big fish; however, I do reel the fish in as fast and comfortable as I possibly can to prevent full exhaustion. The release is then followed by proper fish reviving. The PA Fish and Boat Commission offers a really good guide on it.

Regarding (B), I time myself to keep air exposure to a minimum. Smaller Species are thrown back after a quick photo and most of my catches do not pass the 2 minutes margin for bigger fish. If the fishing environment and circumstances allow, I try to unhook the fish as closer to the water as possible (if not in it).

Regarding (C), I don't intentionally target Species of fish that have a high mortality rate under high water temperature levels. Some of our local "soft/sensitive" Species include the Walleye and Wild/Stocked Trout.  

Regarding (E), years ago I used to target spawning populations of Largemouth Bass without knowing about its consequences. After reading several research papers and consulting the law, I no longer target bedding Bass or any other bedding Species. Targeting bedding Bass is not only bad for its future populations (this will be discussed further below), but it's also illegal in PA. I'll copy and paste the entire sentence from the hyperlink that was given above: "It is not a violation of the bass regulations if a bass is immediately returned unharmed to the waters from which it was taken. It is unlawful for an angler to cast repeatedly into a clearly visible bass spawning nest or redd in an effort to catch or take bass."

Summarizing, as a conscientious C&R angler I recommend all anglers to follow as many of these trends as possible. If you truly love the sport and love the fish that you catch, I'm sure that you will be able to make a couple efforts to maximize their survival rate. After all, it's just in our human nature to do what is best for what we love.

--- Fish Anatomy and Physiology: What Happens during the fight? ---

It's time for some science talk, folks. In order to explore this "angling duration" topic to a full extent, I'll have to guide you through some basic fish anatomy and physiology. After all, without knowing what exactly is happening inside of a fish during a fight, one can't possibly define the angling duration to be "too long" or "too short." 

I promise you that I'll try to keep this as informative and exciting as possible! Please keep in mind that I did take college level courses in Anatomy and Physiology and Molecular Biology; therefore, I do have an idea of what I am talking about here. Heh.

So...you got the bite and set the hook! Fish on!!! If it's a big one, soon the drag starts to scream, meaning that the fish is trying its best to swim away from you. You pump it up; start gaining ground, and soon the fish is at your disposition -- ready to be scooped up. This is exactly what I remember from all those Rapala fishing video games. As a matter of fact, most old school fishing games had a little "energy bar" for the fish at the top. Ultimately, the objective of the game would be to "tire the fish" by depleting its "energy bar," so you could bring in your catch.

If you think about it, reeling in a fish is the same thing as giving it plenty of exercise! From a video game perspective, the fish starts with 100% of its available energy (full bar). The main difference between the video game scenario and real life catching lies in the fact that by the end of the real life fight, the fish's remaining energy will actually depend on how long the fish fought for! In other words, the fish's energy doesn't necessary have to be totally depleted for the angler to land the fish (having a net always helps in this case).


Here is a screenshot of Marine Fishing by the Sega console (2000). The bar on the bottom represents the amount of "energy" left in the fish. Once the bar is depleted, the fish is "tired out." Photo Credit: Video Game Critic.

Now, let's convert this video game scenario to proper Biology! It's well known in the body of C&R research that angling duration is directly proportional to physiological disturbance. Therefore, the longer you play the fish, more exercise it will have to do. More exercise results in more physiological changes, such as increased heart ratio and depletion of energy stores. The main question here, however, is "what type" of exercise are we talking about. In the field of Biology, there are two types of exercises: aerobic and anaerobic

Aerobic exercises are "light" exercises where the organism can use its oxygen as a source of fuel/energy. From a human being point of view, that would be the same as walking or jogging at a pace. Your heart ratio and your breathing spikes; however, oxygen can still be carried from your breath to your muscles, empowering your cells to sustain the strain. From a fish's perspective, that would be a fish swimming in the Lake at a constant velocity. For aerobic exercises, lactic acid is not produced and built up in muscles. In other words, the organism doesn't really get "sore" the next day.

Anaerobic exercises are "heavy" exercises where the organism can no longer use oxygen as a source of fuel/energy. From a human being point of view, that would be the same as sprinting -- running at full speed for a short amount of time. At this point, oxygen alone is not enough to provide the organism the energy it needs. Therefore, glycogen -- the "storage form" of glucose -- gets used instead. From a fish's perspective, that would be a fish giving short swimming bursts in pursuit of its prey. For anaerobic exercises, lactic acid is formed as a product of glycogen depletion. Since glycogen is mainly stored in the muscles, its byproduct builds up over time. The lactic acid is actually what is responsible for the "soreness" and "fatigue" that happens the next day.

For those who are more visual, here is a nice diagram of the Glycogen-Lactic Acid cycle:


A nice homemade diagram of the Glycogen-Lactic Acid cycle. Glucose is transformed into Lactic Acid during anaerobic exercise, resulting in the production of some ATP (Adenosine triphosphate). Over time, the lactic acid slowly gets transferred to the blood stream and then to the liver, where it's transformed once again into Glucose. The transformation of Lactic Acid into Glucose is called Gluconeogenesis, and it requires ATP.
  
Thus, you should know by now that those "swimming bursts" that fish do when we play them are an example of anaerobic exercise. In other words, oxygen alone is no longer enough to sustain all the strain from the exercise. The fish's swimming bursts are driven by their white muscles, resulting in the depletion of their energy storage. Every time a fish pulls your drag or bents your rod, a little bit of its Phosphocreatines -- the fish's version of glycogen/energy storage -- and ATP are depleted. The fish also suffers from lactic acid build up in their muscles. Therefore, the longer you play them, more "sore" and "fatigued" they will get afterwards.

--- Fish Anatomy and Physiology: What Happens after the release? ---

Now you already know exactly what happens to a fish when you are playing it. Summarizing it, the fish goes through a stage of intense anaerobic exercise. It uses its energy storage (i.e. phosphocreatines and ATP) for short swimming bursts, which in consequence causes lactic acid build up in their muscles. In the Glycogen-Lactic Acid cycle diagram, that would be exactly what is happening on the right side of it.

Then, as one would expect, the left side of the diagram would be the "recovery time" for the fish: when the lactic acid gets transported from the muscles to the liver and something similar to gluconeogenesis happens (in fish, the lactic acid would be transformed once again into phosphocreatines in their liver). It's also at this stage that the fish takes its time to rest and recharge its energy storage. As bad as it may sound, this "healing stage" is really the same as having a crippled fish with low immune system during the amount of time that it takes to heal.

Since the fish is released with almost all of its storage depleted and a high amount of stress, the same doesn't really have the necessary energy to even feed after release. Can you imagine then if it were spawning season or migration season for the fish that you caught? Then, as mentioned in (E) way above, that would be extremely damaging for its offspring: in terms of migration, it would get delayed for that specific fish; in terms of protecting a nest during spawning season, the fish wouldn't even have the strength to chase away predators. If we were talking specifically about a bedding Largemouth Bass, the Sunfish would be all over its eggs and daddy wouldn't be able to do a thing until after a while.  

Therefore, ultimately, the main problem lies in the amount of time necessary for this healing process to happen. Most anglers tend to believe that the released fish will recover in a matter of thirty minutes or so and it will be as good as new! Well...it doesn't quite turn out to be that way. As a specific example, a research conducted in 2006 showed that it takes a Largemouth Bass as much as 12 hours after release to go back to its normal resting state, taking in consideration an angling duration of 5 minutes. Now, of course nobody really takes 5 minutes to reel in a Largemouth Bass. Therefore, using mathematics, we can estimate that it takes the fish as much as 2-3 hours to recover for an angling duration of 1 minute! Notice that this data can only be applied for the Largemouth Bass, as the healing time varies from Species to Species. 

The healing time not only varies from Species to Species, but also varies according to the different dependent variables that we have mentioned before -- the "trends." In other words, a fish that was exposed to air for a long time, after fighting an intense fight, miss handled, and perhaps dropped on the floor, will heal much slower than a fish that fought for a shorter time and was handled correctly. That's exactly why we want to follow these trends for proper C&R, so that the fish heals as fast as it can. Eventually, that includes reeling in the fish as fast and comfortably as possible, so that its energy storage is not completely depleted after release.

--- To Play or not to Play the Fish ---

After all this Biology talk, everything boils down to our main question: can we actually take our time and "play" the fish and still ensure that it survives after we release it? And the answer is: it depends. Before going deeper in this subject, here is a list of mortality ratios by Species from a research conducted in 1994 by Muoneke and Childress:


Table 1: mortality rate range after release for recreational fishing using a hook and live bait (not artificial lures). The dependent variables in the study were water temperature, salinity, depth, and oxygen available.  

Note that this table is not entirely accurate because each data entry was taken from a different research paper. In other words, Muoneke and Childress pretty much compiled a bunch of research papers on hooking mortality in the field of recreational angling. The dependent variables for each individual research were not the same! For example: in one research, they may have used treble hooks. In another research, they may have used j-hooks. In one research, the local water temperature may have been 60F. In another research, water temperatures were around 40F. The usage of live bait was the only dependent variable that was the same for all the data on this table. In conclusion, this table is only useful for us to see how "sensitive" a species of fish is in comparison to another. No other conclusions should be drawn from it.

From the table, we clearly see that some Species are more sensitive than others. A higher mortality ratio indicates more sensitivity. The Trout family, for example, has a natural higher mortality compared to other Species of fish. The lowest mortality ratios were from the Esox family (i.e. Pike, Muskellunge) and the Smallmouth Bass, probably because the researches were conducted in places where water temperature was low (recall: higher water temperatures result in less oxygenated water; therefore, higher stress on the fish). On the other hand, Channel Catfish came up with a pretty high mortality rate, probably because the research took in consideration the amount of fish who swallowed their hooks. Largemouth Bass and Striped Bass got a whooping 56% and 69% mortality ratio, since we were dealing with live bait and not artificial lures (for artificial lures, their mortality ratio decreased drastically).

Summarizing...As one can see, it turns out that it's not as simple as expected when it comes to caring for our fishes' survival. A person can't simply barge in and tell someone that "he is killing the fish for playing it too long." Ultimately, it really depends on what type of fish is being targeted; what type of gear and technique is the person using; what time of the year is he fishing; what is the level of oxygen in the water; if he is following proper C&R procedures; etc. Too many dependent variables!!! So, I hope you folks get the idea when I say that "it depends." Should you play the fish or force-fish it? Does it decrease its mortality rate after you release it? It really depends!

--- Conclusion ---

Different Species of fish have different sensitivity when it comes to different stressors in the field of Catch-and-Release fishing. However, one thing is certain: despite the Species, an angler should reel in the fish as fast and comfortably as possible! In other words, one should always try to minimize angling duration. That doesn't necessarily mean "force-playing" the fish -- it means to land the fish at a first opportunity without wasting any additional time. Fishing accessories such as a net should be used.

Force-playing a fish should definitely be practiced under extreme circumstances or while fishing for smaller Species of fish. For example: fighting a sensitive fish Species (i.e. Walleye) or post-spawn fish during high water temperature levels; or Micro-Fishing in a Creek. That is to prevent too much Lactic Acid build up in their white muscles and depletion of energy sources such as phosphocreatines and ATP, so that the released fish can return to normal functioning as soon as possible. Sensitive fish will be able to have enough oxygen to recover and smaller fishes will have enough energy to run away from predators.  

To maximize the survival rate of released fish, a Catch-and-Release angler should also be pro-efficient with the other trends related to safe fish handling: wetting its hands before handling the fish; keeping the fish outside of the water for a limited amount of time; constraining the fish from injuring itself; using gear that prevents the fish from swallowing the hook; etc. A proper revival for bigger and trophy fish should be practiced until the fish has enough energy to swim away on its own (the process may take up to 5 minutes).

If all of these notes are taken, an angler should have absolutely no problem playing a fish comfortably, enjoying the fight and the entertainment that angling provides, all while ensuring the fish's safety after release.


After a long and intense fight with a good fish, just putting it back isn't enough. If circumstances allow, bigger fish should not be "splashed" back in the water. They should be placed in the water and gently revived.  

Best of luck for all of us,

Long Days and Pleasant Nights,

Sincerely,

Leo S.

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