Fishing has been a way for people to gather food as long as we have been on this earth. Fishing methods have evolved from catching fish with our hands to today’s deep-sea super trawlers that trawl the waters clean for immense amounts of fish. For some odd reason we humans have the dumb idea that our fishing waters have endless amounts of resources, and that everything that happens under the water surface kind of is a mystery. Today we know different. We can’t just dump garbage in the ocean. It spreads, and pollutes, and worst of all, it kills.Our fishing resources are not endless either we see today that some species have gone extinct, while others no longer reach the immense sizes that they used to. It is about time we acknowledge the facts, and start working with nature in stead of against it, or we will soon find our oceans, rivers and lakes dead.
One of the first clues of human influence on the waters of our earth was that when rivers that previously stocked migrating salmon died and the salmon would stop running. This was back in the days of the first water wheels, and dams. a village would build a mill or a saw mill, and the dam storing the water to run the mill would block the local river or stream so the salmon were stopped from migrating. No one complained, because there where more rivers to take of, and there was more than enough fish to go around. After the industrial revolution things started to change rapidly. Not only did huge dams block the rivers, but also trash and chemicals that humans dumped in the lakes and rivers would have their effect.Over half of the rivers and lakes world-wide where in a matter of a few decades heavily effected. Together with the industrial revolution the world’s population started to explode. Soon not only industrial activity was destroying the rivers and lakes, but also sewer from homes and farming. In addition we started to see the effects of the rapid development of more effective means of fishing. First off where lakes and rivers where the fish started to disappear. Later we started to notice changes in the ocean fishing. Blue-fin tuna. A fish that can grow to sizes over 600 kg where suddenly not caught in large sizes any more. The herring fishing started to fail as the herring where heavily over fished. The whaling industry failed, and the eel population is down to 10% of what it was 30 years ago.I could go on and on to the hundreds of species of fish stocks that are crashing all around the world, but that would take me weeks to dig up all the research, and explain it all, so let’s go back to the basics.
30 years ago, as a teenager I was living on the west coast of Norway. Most lakes and rivers there have only one or two species of fish. Trout and Arctic Char. Trout and Arctic char usually go well together. The trout stick to feeding along shore on insects and small fish, while the arctic char stay in deep waters, feeding on plankton, and insects. What I soon realized was that the further you got away from humans, the larger the fish got in the lakes. Of course there where some few exceptions, but these where big lakes with few people fishing in them, or lakes that where close to human activity, but for some reason not exploited by humans. So what to do to get bigger fish in the local lakes ?
Well, first off the fish would have to get the opportunity to grow bigger. The lakes where over populated with small fish, and most of their food eaten away.
First off I needed to pick a lake or pond for my experiment. Second , I didn’t want anyone to sabotage my experiment by fishing in the same waters as me, and pulling out the fish I didn’t want taken out. I ended up selecting a small pond in the middle of a small town. The only people who fished there where children, and they usually let their fish go back in. The pond was small 150×100 meters in size, and heavily populated by small trout, and the odd eel. The trout where in average 50g in size, and the eels where no problem for my project, as they where few, and didn’t have much of an impact on the trout. No one would eat the fish there as they taste like mud due to their diet being mostly mosquito larvae that build tubes in the muddy bottom. Most other water insects where more or less gone from the pond due to the big numbers of small fish there.
With the pond being so small there was no problem regulating the population of fish just using a fishing rod. I made sure to visit the pond often, and pull up as many fish as possible. I made sure that the fish over the average size were released, while the smaller fish I took home to feed our cat. I measured every single fish that I took with home. Both in weight and length, and figured out their K-Factor. I also checked what they had been eating, and noted which fish where due to spawn the coming fall, and their age. After a year I noticed a small increase in the average size of fish, but no notably difference in the number of fish that I caught on each trip. In average a walk around the pond would give me about ten fish. This didn’t change ever during the project. I changed my max size as the average size got bigger. Each year the average size for the trout got bigger, and each year I changed the max weight to a little larger size. After about three years I started to notice a difference in the fishes diet.
In stead of only having small mosquito’s and mosquito larvae in their bellies, they now started to have a wide range of insects on their diet. May flies, Dragon flies, stone flies, caddis, and even the odd gammarus. Some of the fish started also get a slight pink color to their meat, something that showed that the numbers of gamamrus, and animal plankton had started to grow. Unfortunately I ended up moving to Sweden, so I had to cut my project short. The idea was to get the average size of fish up to between 1 and 2 kg, but I had to stop when the average size had reached around 500g, and there had been caught fish in the pond that was almost two kg. A new job popped up, and I had to move over 800 km away.
Since then the pond has declined. The average size of fish in the pond should have gotten over one kg to ensure a healthy stock of large predators to keep the population of fish in check. Five years after I ended my project, the average size for the fish in the pond has gone down to around 250g
Now recently I got my theory proven by scientists. A recent series of research has been published that shows that the Cod in the Atlantic ocean have gotten smaller, and started to spawn at an earlier age. The reason has been over fishing of the larger fish in the cod population. Scientists has been making studies based on guppies to try to figure out how fish react to over fishing, and selective fishing of various age groups of a fish stock.
It shows that the best way to maintain a healthy stock of fish is to target the smaller fish. The fish that are just around mature age, and let the biggest fish in the stock go free. First off the genetic properties for fish to grow fast, and get extra big lie in the largest fish. Second there are very few of the largest fish in a fish population. The younger and smaller the fish is, the more individual fish you will find.
Some fisheries. specially fresh water fisheries have started to change the way they think in regards to what method to use, and which fish to target. In stead of gill nets, many have started to use traps that catch the fish alive. this way they can release the large breeders, fish that are too small, and unwanted species of fish.
Selecting which fish to take up and which to let go is the clue. This is where Catch & Release fishing comes in. Not only to the hobby angler but also the commercial fisherman. As for the angler, Pure C&R fishing is simply pure animal cruelty. Nothing more, Nothing less. The angler’s point of view is not interesting to hear at all, because it is not the angler stuck to a hook and fighting for his/her life. Fishing is in it’s own purpose to catch fish for food, not to torture the fish. If you want the nature experience, bring your camera instead of the fishing rod. C&R can however be justified if you are releasing the big breeders, and sticking to a bag limit. This not only allows you to catch big fish, but it also ensures that you can take a fish or two home for food, and that your Children and grandchildren will have the chance to experience the same quality if not better fishing than you did. That’s what we all want, isn’t it ? Lakes, rivers and oceans filled to the brink of lots of fish ?
Some of the sources for this article:
Fisken blir mindre og mindre
Fiskeri påvirker fiskens gener
Fishing Effects on Fish Population Structure and Ecology
Overfishing is emptying the lakes and rivers
Dams and Migratory Fish