An ultrasound sensor is a tool that is used to spot marlin. However, the gadgets for fishing are not cheap. Unless you are someone who is dedicated to solely fishing for marlin, be careful of the purchases that you make. Often times companies will make products that are specifically designed for a certain type of fishing, in a certain location, or even a region. When people think of fishing, they automatically think of rods, reels, and bait. However, you cannot underestimate the power of the tackle box because it plays an important role in the success of your fishing expeditions. Many people covet their tackle boxes because they represent a lifetime of trials and tribulations regarding what methods work for which fish. Those who love the ling are welcome to pay its tribute at the annual International Eelpout Festival on Leech Lake in Walker, Minnesota. Three full days commemorating the ugliest fish in the sea begin with an Opening Ceremony, complete with Torch Lighting. Entrants are encouraged to use their imagination when constructing their fishing shelter, as prizes are awarded for the most lavish structure built on the lake. Another factor that weighs heavily on where you will find certain fish is oxygen. All fish must have a certain level of oxygen to survive. Some fish, such as carp, survive on less oxygen than fish like trout. The living plants within a lake or stream directly affect the amount of oxygen in the water. There is no better way to instill a sense of accomplishment in your kids than to allow them to help you with "grown-up" jobs. Depending on how old they are, assign them certain small things for which they are responsible. Some of these include ensuring that everyone has a personal floatation device and letting them coil a line. Perhaps the most recognizable tool for fishing is the hook. No one knows for certain, but it s quite probable prehistoric man was using some form of a hook over 40,000 years ago. Experts have had some problems pinning down exact dates since they know most of the materials used back then were most likely wood and not very durable.