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Blog posts and articles from SAFER Lab

SAFER Blog: Can Catch & Release Kill?

Catch and Release (C&R) has become the buzz word for responsible, environmentally friendly fishing. While it’s always good to release a fish rather than kill it, C&R may not be as harmless as we thought. In fact, it may even kill!

Right now, you may be thinking to yourself, “that’s totally illogical! The fish is fine, I’ve seen them swim away quite happily” and in some ways, you are right. Most fish don’t die on the spot while you are handling them, it’s what happens after they are released that’s dangerous. Because, as you well know, that fish is not alone in the water, there are many other fish, slightly bigger fish, that would quite happily gobble up a dazed and confused fishy swimming around like it has had too much to drink. But why is the fish so disorientated after it has been released? Well think of what the poor little guy has just been through, he’s swimming around happily, minding his own business when he comes across some food just sitting there, so naturally, he decides to take a little nibble. On the first bite, however he finds that his face has been impaled on a sharp hook and he’s now being dragged from the water! He swims as hard as he can, harder than he has ever swam before but it’s no use, he’s suddenly hauled unceremoniously out of the water. He’s poked and prodded, measured, held out for some random person to take a selfie with him, all the while unable to breath. It’s like running a hundred-meter sprint only to have someone at the finish line grab you and hold your head under water for a minute, you’d be a bit light headed and disorientated too. Not just disorientated, but a bit stressed and freaked out as well. And in some cases, it’s actually these stress hormones that can attract predators to the fish. But say the fish can avoid the predators and find a nice spot to hide out for a while, it doesn’t end there. What the fish has just gone through may have some long-term health effects. The fish will have a hooking injury and may have had some slime and scales removed while it was being handled, and while these injuries are not necessarily serious or life threatening there are some health risks associated with them. You see, a fishes’ scales and slime are not just there to make it look pretty or help it swim better in the water, they actually protect the fish from germs and fungus. So, when slime and scales are removed the fish is far more vulnerable to infection and fungus growing, particularly in areas where the fish is injured. Remember those stress hormones I mentioned earlier? Well those can affect the fishes’ long-term health as well. We all know excessive stress is not good for us, that’s why we go on fishing trips, and it’s the same for fish (the stress bit, not the fishing trips). Excessive stress can weaken a fishes’ immune system, making it more vulnerable to diseases and infection. It can also affect a fishes’ reproduction, causing it to produce less eggs or sperm and thus have fewer offspring.

Now the confusing part is that when it comes to C&R no two-fish species are alike. Some can go through all this and be perfectly fine, with little or no deaths. While other species can have extremely high mortality rates within the first 24 hours of being caught. This makes it very hard to draw up best handling practices as what works for one species may not work for another. It is the job of the scientists (a clan to which I proudly belong) to find out how C&R effects certain species, and this is what I did along with some other fishy scientists. We had a look at how the Cape stumpnose holds up in a C&R event and what we found was pretty interesting (well we thought so at least). Stumpies that were held out of the water for 90 seconds were more stressed than those who were held out for only 30 seconds or less. Fish that were allowed to recover for an hour before being released were much less disorientated and on the whole, there weren’t too many deaths, only 7% mortality rate. So stumpies are relatively resilient to C&R but that’s just looking at the short-term effects, we still don’t know how they hold up in the long run and that’s just looking at one species, there are still a lot of species out there with no information on how C&R affects them.

But it’s not all doom and gloom, even though we don’t have specific information on every species there are still some thing we can do to give the fish we catch the best possible chance of surviving. One of the best things you can do is try and minimize the time you keep the fish out of water, under a minute is best. If you don’t have a timer handy, just hold your breath while the fish is out the water, when you feel the need to take a breath, put the fish back in the water. If you don’t feel like rushing, or you want to hold on to your fish for a bit longer, have a bucket of clean water close at hand when you are fishing. When you land a fish, rather than holding it out the water while you take the hook out, just pop it in the bucket of water, then you only need to take it out for a photo and that doesn’t take very long. Using barbless circle hooks will make removing the hook much easier and prevent further injury to the fish. Make sure whenever you handle a fish to always have wet hands, never hold a fish by its gills (that’s a sure-fire way to kill it) and try to avoid dropping it or lying it down on the ground. If your fish gave you a good fight, the chances are it’ll be pretty exhausted. So, if possible, having a recovery bucket would be a good idea. This is just a bucket (preferably dark in colour and not to small) that has small holes drilled in the bottom which you can place in the water (at the bank of an estuary or in a rock pool) to allow the fish to recover for a while before you release it (if your fish is too big for the bucket or only just fits, it is better to just release it). This reduces the chance of your fish being taken out by a predator because it will be much less disorientated and able to take evasive action if necessary.

These handling techniques may seem silly, but I promise you they will make a world of difference to the fish. You might be thinking “So what if one or two fish die, that’s not going to make a difference to the population” but with close on a million recreational anglers in South Africa alone those one or two fish start adding up very quickly. So, it is our responsibility (as that rare and special breed of people who love fish) to ensure that every fish we have the privilege of coming in contact with, has the best chances of survival.





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