Catch and Release or Catch and Kill?

By Scotty Kyle

As a youngster growing up in Scotland this was simply not an issue, if the trout was big enough, you killed and ate it, otherwise you let it go to grow big enough to eat. It is now 40 years down the line and I’m in South Africa and rarely kill any fish. But I do catch quite a few and thus have to decide each time the fate of the fish that I have caught “for fun”. The decision is sometimes complex as we now know much more about fish and that many species are under ever increasing pressure. Laws have been created in many countries to try to ensure wise use and, in some countries including Switzerland, it is mostly illegal to release a fish you have caught, regardless of size, in order to avoid inflicting “more trauma” on it. 

A few days ago I caught a beautiful rainbow trout, an alien in this country, in a farm dam where the species does not breed and all the fish are stocked from fish farms. It was the largest rainbow trout I have caught, though I have rarely fished for this species for decades, but my wife had wandered off looking for birds and thus could not photograph it. The fish was magnificent, had given me a wonderful experience and a memory to last a lifetime but should I kill it or let it go? 

Various questions passed through my mind such as will my offspring believe me if I just tell them, can I kill something that gave me such joy, would it survive the capture, and I wondered if such a large fish would still taste good? On the other hand it was an alien, would not be able to breed and thus its strong genes were lost to the next generation anyway and the farmer had told me I could kill some fish.

What Factors Determine the Decesion to Release?

Until I recently retired I was a government fisheries scientist and, among other things, ran several fish mark and recapture programmes that provided us with critically important and really interesting information on fish ecology, behaviour, movement, growth and catch rates. The result was that I needed to tag and release all the larger fish I caught. That scenario has now changed but, in the meantime, I had learned that many fish stocks have collapsed, species have been driven to near extinction, and the biomass of fish in the open ocean had probably been reduced to well under half by man’s depredations.  

Now, I fish for fun and make no apology for doing so. I eat meat and while I do not enjoy the concepts of abattoirs, chicken farms and such things, I have come to terms with them. I detest cruelty to people or animals in any form but accept that between an animal or fish living in the field or water, and my eating it, it has to be caught, killed and processed.  

So, on what basis should a reasonable, fairly intelligent person decide the fate of a fish he or she has caught? There are several important aspects contributing to this decision including the legal, ecological, ethical and practical. The “bottom line” should be the local law which often lays down which species and sizes of fish may be caught as well as when, where and how they may be caught and if they may be killed.

Closely allied to this feature is the ecology of the fish which should be the basis of the law. Spawning migrations and aggregations may need protection, as well as any large fish about to spawn. In some areas laws require all small fish, or fish of certain invasive species, to be killed. In other areas small fish must be returned alive and there is a limit to the number of larger fish that may be killed. Sensible laws protect breeding stock, spread the available fish that may be killed among many anglers and prevent unwise fishing methods. 

a big fish

The Ethics of Fishing

Ethical considerations have gained traction in recent years, and caused some angst. They need to be acknowledged and addressed. I kill mosquitoes, cockroaches, rats and mice that chew holes in my roof and I enjoy a good barbecue or nice piece of rump steak. I also really enjoy catching fish, especially if I made the fly myself, and accept that it is probably not pleasant for the fish and, even with great care, some fish will succumb. Some people hold that capture is traumatic for fish but, while some distress must take place, there are ways to mitigate this. 

Evidence suggests that capture is not always too damaging or harrowing. During fish capture for tagging I have recaught the same fish within an hour of the first capture and tagging. I have caught and tagged a large fish in the evening and recaught it the next day. We have recaught many fish repeatedly and one very special tagged marine fish in our province has been recaught at least five times. 

Impractical decisions are also, at best, pointless. If there’s a good chance that a captured fish will die then it is futile to let it go. Many people hold the view that most released fish do die, either soon after capture or as a result of infection or injury during capture. The reality is that some fish species are very easily damaged, some fishing methods often result in injury and playing a fish gently can result in its complete exhaustion. On the other hand, if a suitable fishing method is used to target large enough individuals of a rugged species, very low mortality rates can be achieved.

How to Reduce Mortality of Released Fish

An aquarium captured 30 rock salmon (Lutjanus argentimaculatus), very similar to the mangrove snapper, on rod and line in an estuary in my area of responsibility. To reduce injury and death, barbs were squashed, mild steel hooks were used and the fish were landed as rapidly as was reasonably possible. The fish were placed in a trailer tank and taken over 400 kilometres to the quarantine facility at the Aquarium. Three years later all 30 fish were still alive and had grown substantially. 

To me this example shows that, with a little experience, care and thought, most fish of many species can survive capture and release. It can thus be practical to release fish as there can be a very good chance that they will survive. Anyone may reduce fish capture morbidity and mortality by squashing barbs, not using stainless steel hooks, using circle hooks, landing fish as rapidly as possible and replacing treble hooks with single ones. It is usually much easier to unhook a fish and it often causes less injury to the fish if a single hook is used, as can be seen with this giant trevally. Taking photos in or very near the water also reduces fish injury and trauma.   

If we go back to my childhood in Scotland the local herring, cod and lobster fisheries were all collapsing due to unmanaged overexploitation. Now, due to improved management things are improving on many fronts but severe damage was done. We have learned a lot and mostly changed our fishing for the better and many of our fisheries are better, if not well, managed. The result is that individually we are now in a much better position to decide rationally and objectively on the fate of the fish that we catch. 

The author with a big trout

The Ultimate Decision of Kill or Release

So, if we go back to my rainbow trout, I finally rationalised that this large fish could replace three smaller fish in terms of food production for my family and so I quickly dispatched it. Later that day I was mocked and ridiculed by my three “children”, now all ardent anglers around 30 years old, for killing the fish just so that I could show it off to them. I checked up, however, and found out that they only live about six years and mine must have been fast approaching its dotage. There were otters, eagles and piscivorous birds in the dam which could explain why we do not often see old dead fish. In hindsight, I am now comfortable that my decision to kill that fish was correct. I ate almost all the fish, including the skin and head, and there was very little waste. On the other hand if I now catch a very large brown trout, also an alien here, I will probably let it go. It seems that brown trout can live for over 25 years and so there would be a good chance that the fish could live for several more years and grow even larger. 

The net result is that the decision on the fate of a captured fish, beyond the legal requirements, is entirely at the discretion of the angler. While ethics are important they are very personal and, in my view, no one should be arrogant enough to inflict his or her standards on anyone else. In my view the decision should be made in terms of the needs and realities of the angler, the fish and its population plus the “greater good” of other anglers and the environment. Killing fish in order to simply show them off to others should be a last resort in these days of ubiquitous cellphones and when so many fish and fisheries are still under enormous pressure. Fishing should be a source of great pleasure and worrying and stressing about the fate of one fish should not, and in my opinion need not, be a part of the fishing experience. 

Leave a Reply