Bank lines are a form of fishing similar to trot lines. For those that do not know about trot lines, they are a way to fish without being present watching the pole. Below is a diagram of what a bank line usually looks like.
To make a bank line, all you need is some heavy fishing line (I recommend 100+ lb. test), swivels, and hooks. You will also need two anchors, one on land and another for the water. The water anchor can be a rock or branch, make sure the anchor isn’t too small or too large—you will need to throw it out as far as you can in order for this setup to work well. There are many custom things that can be done to a trotline, but at bare minimum you only need line, knot-making skills, swivels, and hooks.
This article is my favorite for making a simple trotline. If you have the time and live in an area where fishing would be important in a survivalist situation, I suggest making an emergency trotline ahead of time. They take up very little space and weigh next to nothing, but can be a fair amount of labor upfront to get it correctly setup.
You need to know about bank lines because they are efficient! People commonly drop off these fishing rigs in the morning and pick them up at night or the next day, thus you can be off getting other things done while the trotlines do the fishing for you. Keep in mind, however, that depending on the presentation, many trot lines and bank lines end up getting stolen by other anglers. This is why I suggest a bank line rather than a trot line—keep the rig low profile.
In the diagram above, the line is tied to a tree, but sometimes people will bury a PVC pipe in the mud and tie the line to the PVC pipe to make everything as hidden as possible. If you were to survive by yourself hiding the bank line isn’t too much of an issue, but if there was a survivalist situation where many people were looking for food to steal, hiding your bank line is a must. When checking/putting out your bank line make sure nobody is around to watch as well.
Depending on the area you live, bank lines can draw up many different kinds of fish—most prominently catfish in the south. People usually use them on creeks or rivers. Fish can sometimes be fairly discriminating of bait used on a trot line. In the true spirit of efficiency, I think bugs or small seeds/fruits found around the body of water would work best as bait. Scrap meat from another meal that would work well too. In general, the stinkier and more rotten the bait is the better. Stinky, rotten bait broadcasts scent in the water and brings fish in from further away.
If you aren’t catching anything, the fish either aren’t there or they do not like the bait. Experiment with some different baits on the line to conclude if they like one bait or another. If they aren’t taking any of the baits the fish probably aren’t around—move the bank line to another safe location. If you don’t know where to put the trot line in the first place, find a place that has some deep water and looks like an “active” area. By active, I mean an area that has a fair amount of wildlife around—birds, bugs, frogs, minnows, usually when there are these organisms around, the larger fish are never far away.
In conclusion, a survivalist scenario requires you to cover all your bases because you never know what will happen. Perhaps you get an injury where you cannot go out and forage/hunt for food—bank lining is a good alternative. While bank lining can be fairly easily done with the right supplies, it doesn’t hurt to have things sorted out ahead of time. Depending on your situation, it may even be worth it to stake out some areas ahead of time to figure the best or most hidden places to put out the bank line. In terms of saving calories and remaining efficient with time, bank lines represent one of the most efficient survivalist strategies out there.