Fish hook designs, shapes, and materials are all variable depending on the intended purpose of the fish hook. Fish hooks are manufactured for a range of purposes from general fishing to extremely limited and specialized applications. Fish hooks are designed to hold various types of artificial, processed, dead or live baits (bait fishing); to act as the foundation for artificial representations of fish prey (fly fishing); or to be attached to or integrated into other devices that represent fish prey (lure fishing). The fish hook or similar device has been made by man for many thousands of years. The world's oldest fish
Fishing bait worms can grow up to 7 inches (18 cm) in length, but usually are between 3 and 4 inches (7–10 cm) long. Worm farmers also offer other worm species for bait, depending on availability, which usually depends on the prevalent climatic conditions. The capture, transportation and culture of bait fish can spread damaging organisms between ecosystems, endangering them. In 2007, several American states enacted regulations designed to slow the spread of fish diseases, including viral hemorrhagic septicemia, by bait fish. Because of the risk of transmitting "Myxobolus cerebralis" (whirling disease), trout and salmon should not be used as bait. Anglers