Here's some information take from my forthcoming book "The Modern Hunter-Gatherer," which delves into procuring wild foods:
I have two setups: One is a low-tech fishing-kit and the other is a collapsible fishing pole that you can purchase from most gear shops for $25 (reel and lures included).
My low-tech kit for the backcountry is pretty simple: two dozen assorted hooks secured on a safety pin, a dozen split-shot sinkers, a small roll of 6 lb. monofilament line, a few artificial lures, and some small bobbers. My kit is perfect for catching freshwater panfish like bluegill, sunfish, and perch. You will have to adjust your own kit to fit your region and the fish you are after.
For bait, there's no substitute for a juicy worm! Short of that, I have used grasshoppers, grubs, crickets, and moths. If no live bait presents itself in the region, then I have my fallback artificial lures.
With this system of fishing, I don't use a pole but rather cast off of my hand, a stray pop can, or a smooth stick. I have probably caught more fish on survival outings using this simple "Hobo reel" than through using any of my expensive rod and tackle sets, most of which are gathering dust. I was first introduced to this setup in the Boy Scouts, but have found it to be pretty universal and still in use by native cultures throughout the world. In fact, a friend who recently returned from a jungle survival trip in Guyana said that the natives there still use this system as the primary means for procuring fish.p
If you would rather purchase a pre-made survival fishing kit, then I would consider picking up one of the fine kits from the BestGlide Company in Texas. I obtained a sample to try out and was really impressed with both the quality and well thought out components that went into their Standard Kit. This little beauty will take care of your emergency fishing needs if you are not inclined to assemble your own.
For a longer wilderness trip, I will bring along a collapsible fishing pole with a quality Daiwa-brand reel and an assortment of artificial lures.
As you can guess, we are not talking about an expensive fishing kit with either of the above setups. If weight is an issue, then pack along the Hobo reel.
Be sure to obtain a fishing license for your state and to follow the guidelines. The rules are in place to protect the ecology of rivers and lakes.