Once you cut a tree down, you can count the number of years it has stood by counting the annual rings around the stump. It might surprise many that you can get a pretty good idea how old a fish is by counting the rings on a single scale.
When we used the big box traps in the St. Lawrence River, we removed a fish from the net, measured its total length and girth, placed a tag on it and, while one person was doing that, the other would count the annual rings on a scale to get its age.
As far as a fish’s sight goes, it varies according to the species. At close range, their sight is exceptionally good, but fades as the distance increases. Here is one for the opticians—the eye on the right side of the fish is connected to the left side of the fish’s brain and the left eye is connected to the right side of the brain. This results in the fish being able to actually see in two different directions.
As far as distinguishing colours, most would believe that their red lures are the best colour and that they retain that colour (from a fish’s perspective) at great depths. Actually, at a depth of 10 feet, the colour red diminishes. Yellow-coloured baits still hold their bright colour at a depth of 50 feet, while at 35 feet, they hold about 40 per cent of their colour.
Surprisingly, green and blue hold 80 per cent of their colour at 10 feet. At a depth of about 70 feet, they retain close to 70 per cent of their bright colour. Fish such as the bass and pike (both shallow water fish) will be attracted to just about every colour. The reason, of course, is the depth at which the sunlight penetrates the water. Deep water fish are attracted to the green, yellow and blue baits because there is less sunlight to affect the colour of the bait.
Now you may wonder, can fish smell? Yep, and so do some of the fishermen I know. Actually, some fish have a very keen sense of smell. Once again, this varies between different species. Like humans and other animals, they do have taste buds on their tongues. Back in my conservation officer days on the St. Lawrence River, I knew one fisherman that used to keep his favorite baits in a container with dew worms. He claimed he was using both smell and sight to catch his fish. Some laughed at him, but I regularly saw him on the river with a fish or two while others were being skunked.
Do fish actually sleep? It may be surprising to some, but they not only sleep, there are fish in the far arctic that sometimes are actually encased in ice. Once that ice melts and sets the fish free, it goes back to normal. That one I have never had the experience with, but I have been told by experts in the trade that it is factual.
Fish do sleep, but the difference here between fish and animals is that fish cannot close their eyes. Generally they will rest on the bottom of the river when they do go to sleep.
What about the feel of pain? We do know that fish are cold-blooded creatures. Being so, many would guess they do not feel pain. A fish does not feel pain like animals do, but there is a sense of pain with fish, although very marginal. Let’s say you, being a human, were to get a hook in your hand. Would you pull back on the hook or ease towards the hook, which would result in less pain. When a fish is hooked, it immediately jerks back. To me, I would say that if there is pain, it is very minimal. I would suggest it is more a resistance, a fight or something along that line of thinking.