Tracking regional consistency in regulatory policies to restrict the sale, possession and transport of priority aquatic invasive species.

One way to measure progress towards effective regional management of the trade in live organisms pathway is through the implementation of consistent regulated species lists across federal, provincial and state governments. These lists identify plants and animals for which certain activities are illegal in a jurisdiction, e.g., importation, sale or possession. However, inconsistencies in regulated species lists may result in an invasive species being legal to sell in some jurisdictions, creating an opportunity for introduction into the region.

The need for consistent policies between Great Lakes jurisdictions to prevent invasive species introductions is recognized as a regional priority by the Great Lakes Panel on Aquatic Nuisance Species, Annex 6 of the Great Lakes Water Quality Agreement, and the Great Lakes and St. Lawrence Governors and Premiers Aquatic Invasive Species Task Force.

In 2013, the Great Lakes and St. Lawrence Governors and Premiers identified a list of sixteen “least wanted” aquatic invasive species that are considered a grave threat to the region’s economy and ecology. Five additional species were added to the list in 2018 (denoted by a * in the below table). The governors and premiers called for specific steps to manage these least wanted AIS, including taking executive action within each state or province to prohibit or restrict the transfer of these high-risk species. They also called for regional collaboration to harmonize related state and provincial policies. The least wanted species are:

Great Lakes and St. Lawrence Governors and Premiers' Least Wanted Species
FishAquatic InvertebratesPlants
Silver carpYabbyHydrilla
Bighead carpKiller shrimpBrazilian elodea
Grass carpGolden musselParrot feather
Black carpNew Zealand mudsnail*Water chestnut
Northern snakehead Marmorkreb*European frog-bit*
ZanderYellow floating heart*
Wels catfishWater soldier
Stone moroko
Tench*

Since the announcement of the least wanted list in 2013, many jurisdictions have made substantial progress to regulate the sale, import, and possession of these species. The figures below reflect the jurisdictions (out of 10; 8 states and 2 provinces) that expressly prohibit each of the “least wanted” species. Some states may regulate species through a blanket restriction, such as prohibiting the sale of all non-native crayfish. The state of Illinois notably utilizes a “white list” approach where a blanket restriction applies to all species except those expressly allowed for sale in the state. The below figures are not intended to capture the status of species under those blanket restrictions and only show species that are specifically named as regulated in a state or province.

Number of Jurisdictions that Expressly Prohibit Each of the "Least Wanted" Species

Fish Species
200820142020
Silver carp81010
Bighead carp81010
Grass carp61010
Black carp81010
Northern snakehead 81010
Zander169
Wels catfish017
Stone moroko036
Tench*145

There are now 5 “least wanted” fish species that are regulated in all 10 jurisdictions, and all fish species are regulated in at least half (5 out of 10) of the Great Lakes states and provinces. Species with an asterisk (*) indicate species that were added to the Least Wanted list in 2018.

Number of Jurisdictions that Expressly Prohibit Each of the "Least Wanted" Species

Invertebrate Species
200820142020
Yabby137
Killer shrimp025
Golden mussel025
New Zealand mudsnail*144
Marmorkreb*001

Progress in regulating invertebrate species has been bolstered by the addition of these species to the "least wanted" list. All of the species added to the original list in 2013 and one species added to the updated list in 2018 were each regulated in more states and provinces after listing. Species with an asterisk (*) indicate species that were added to the Least Wanted list in 2018.

Number of Jurisdictions that Expressly Prohibit Each of the "Least Wanted" Species

Plant Species
200820142020
Hydrilla267
Brazilian elodea167
Parrot feather167
Water chestnut 267
Water soldier115
European frog-bit*267
Yellow floating heart*156

Compared to fish and invertebrates, plants are the most consistently regulated species. However, no plants on the "least wanted" list have yet been regulated by all 10 states and provinces. Regulating invasive plant species is often more complicated than regulating fish or invertebrates, as the authority to regulate plants typically lies with the jurisdiction's agriculture department, rather than the natural resources department. Species with an asterisk (*) indicate species that were added to the Least Wanted list in 2018.

Number of "Least Wanted" Species Regulated by Each Jurisdiction

Number of "Least Wanted" Species Regulated by Each Jurisdiction
200820142020
IL41018
IN51114
MI121921
MN111516
NY41414
OH61114
ONT5516
PA556
QBC088
WI01518

The number of “least wanted” species that are regulated by each jurisdiction has continued to increase. The possession and sale of most of the original (2013) least wanted species are now restricted across most Great Lakes states and provinces.

Harmonization of species regulations in the Great Lakes Basin extends beyond only the Great Lakes and St. Lawrence Governors and Premiers' Least Wanted List. All species regulations for each of the Great Lakes states and provinces have been assessed in the report Harmonizing Great Lakes Regulated Species: Progress Towards Reconciling a Regional Patchwork in order to better understand how consistent each jurisdiction's regulations are and if they regulate the highest risk species, many of whom are included in the Least Wanted List.