Ponds are stocked annually. Fishing is regulated by a fishing license issued by the warden. The license establishes an annual overall limit, or total number of fish a state can catch in a given fiscal year. The limit is referred to as Obligation Authority or an Obligation Ceiling . In other words, more fish are added to the pond each year than can be caught and so the States have a lot of old fish in their ponds.
Many states prefer to keep only certain species, namely shark and barracuda.
Because their annual limit doesn't permit them to take every fish that has been stocked, some states throw back all or most of the steelhead and trout they catch so as not to use up their limit with species they don't like. The Politics of the Pond Old fish are called Unobligated Balances .