CDFW requires the services of vendors experienced in the collection and disposal of anadromous fish carcasses. CDFW Operated Anadromous Fish Hatchery helps manage the population of the anadromous fish in the appropriate river by propagating hatchery raised fish to supplement the number of anadromous fish that would otherwise propagate in the wild. CDFW personnel take all necessary eggs and milt from such fish returning to the hatchery to meet hatchery production goals. While returning some of the surplus anadromous fish carcasses to the river may benefit the ecosystem, some CDFW Operated Fish Hatcheries are prohibited from returning such surplus anadromous fish carcasses to the river. In other instances, a surplus of carcasses may be produced at the hatchery in a relatively short amount of time; and returning a large volume of anadromous fish carcasses would not benefit the ecosystem.