The first braided fishing lines were composed of Dacron, a synthetic fiber, but the line had inferior knot strength, failed to stretch and would often break. It was replaced widely by monofilament lines in the 1940s.
By the 1990s, synthetic fibers such as Kevlar, Spectra and Dyneema were used in braided fishing line to create a line that was both thin and extremely strong.
These fibers were braided together using a complicated process that resulted in a line that was termed "superline;" it doesn't absorb large amounts of water and has no memory, meaning it will not coil up when it is cast out.
Some of the disadvantages of these newer braided lines, such as being visible to the fish, were dealt with after anglers' complaints by refining the production process and making steady improvements to the fibers they are made from.
Saltwater fishermen employ these braided lines because of their strength. Freshwater anglers will utilize them when trolling and jigging for fish, as well as putting braided line on a reel and then tying it to monofilament to allow a smaller-type reel to hold more line.