Statutes Governing the Introduction of Exotic Species
1900 – Lacey Act  (injurious wildlife)
1969 – AFS Conference on Use of Exotic Fishes and Related Problems
1974 – Federal Noxious Weed Act
1977 – Presidential Order No. 11987 which restricted federal support
1980 – National Aquaculture Act - Gainesville laboratory to research   beneficial use of exotic species
1990 – Nonindigenous Aquatic Nuisance Control and Prevention Act
1996 – National Invasive Species Act of 1996
1999 – Executive Order on Invasive Species
The problem started hundreds of years ago when introductions occurred with the earliest European settlers. But, the earliest documentation of introductions began in the 1800s, many of which were intentional such as the Asian common carp and the European brown trout that were introduced by government agencies.
So it began In 1900, the Lacy Act was the first legislation aimed at controlling unwanted introductions.
In 1969, the first American Fisheries Society meeting on exotics was held headed by R.H. Stroud. This was about the time when the U.S. Fish and Wildlife Service started taking notice of problems caused by invasive species and potential problems that may cause.
In 1974, the Federal Noxious Weed Act was legislated.
In 1977 President Carter’s Order restricted all federal agencies from actively supporting projects that would increase the spread of exotics.
In 1980, (A shameless plug for my office), the National Aquaculture Act stimulated the USFWS to establish the laboratory in Gainesville, Florida to oversee development of a research program that will support the use of exotics for beneficial purposes while protecting the environment. That Center is no longer functioning that way, instead is attempting to determine impacts and distributions of all nonindigenous aquatic species.
In 1990, the arrival of the zebra mussel prompted Congress to pass the Nonindigenous Aquatic Nuisance Control and Prevention Act.
This Act was later reauthorized in 1996 as The Invasive Species Act which focused heavily on ballast water and is up for reauthorization in 2001. Finally in 1999 there was another Executive Order to stimulate more research.  Okay, enough.