White perch

Habitat

• Primarily inhabits brackish water
• Also found in near-shore marine habitats, in high densities in pools and quiet areas of medium to large rivers and in the shallows of inland lakes and ponds

Description

• A demersal fish, spanning freshwater, brackish and saltwater habitats
• A silvery-white belly, pale-olive or silvery green on the sides and dark or silvery green to almost black on the back
• Around 127-178mm long and an average weight of 250g
• The body is deepest just in front of the dorsal fin
• There are no barbels and no lines or stripes on the back or sides
• The soft dorsal fin becomes erect when the spiny dorsal fin is pulled erect
• It moves from saltier habitats into more freshwater portions of streams and rivers to spawn
• It moves from deep to shallow waters to spawn in inland rivers and lakes
• Females can produce between 20,000 and 150,000 eggs

Origin and Worldwide Distribution

• The native range is North America’s Atlantic Slope drainages from St Lawrence Lake Ontario drainage, Quebec, south to Pee Dee River, South Carolina
• It was introduced into the Great Lakes through the Erie and Welland canals and is now established in all of them and their surrounding states

Potential or Known Impacts

• Known to consume the eggs of commercially important fish species
• It can become the most dominant fish species in the waterbody, outcompeting natives for food and habitat
• It can hybridise with native fish species, altering and polluting the gene pool

Is it found in Northern Ireland?

• It is not currently present in Northern Ireland

How could it get here?

• Introduction is a result of the intentional stocking of waterbodies for the use in sport fishing and commercial fisheries, from here M. americana has spread through interconnected waterways
• Illegal import, breeding, growth, release, selling and transport of this fish is the most likely reason for introduction today

Management/Methods for Prevention

• Prevention via enforcing the IAS (Enforcement and Permitting) Order (Northern Ireland) ensuring that M. americana is not introduced to Northern Ireland
• Reporting any sightings so that Rapid Response can be instigated
• If Rapid Response is not successful, management can include physical, biological and chemical control

Current Legislative Position (Listed on 02 August 2022)

• This species must not intentionally be brought into the Union; kept; bred; transported to, from or within the United Kingdom, unless for the transportation to facilities in the context of eradication; placed on the market; used or exchanged; permitted to reproduce, grown or cultivated; or released into the environment.

Species Related Files:

RA_Morone_americana_White_perch