Wisner’s property is also home to a number of invasive species such as apple snails (Pomacea maculata), feral hogs (Sus scrofa), nutria (Myocastor coypus), and water hyacinth (Eichhornia crassipes). Where possible Wisner works with agencies, adjacent landowners, universities, and local government to combat their spread. Wisner periodically shares information on how to mitigate for invasive species in mailers to their lessees.
Wisner began to notice the bright pink egg clutches around its St. John the Baptist property around 2017. Wisner joined BTNEP’s Invasive Species Action Plan Team in an effort to learn more about the apple snails and how to eradicate them from the property. Wisner’s property in Bayou Segnette is also plagued by apple snails. Scientists have been studying the snails in the Jean Lafitte National Historical Park and Preserve adjacent to Wisner’s property and on Wisner’s St. John the Baptist property.
This is one of the largest freshwater snails. It arrived in Louisiana from South America through the aquarium trade. First seen in a drainage ditch in Gretna, Louisiana in 2006, it now is found in 30 Louisiana parishes. It is highly adaptive and can burrow into the mud to survive droughts and cold temperatures. The snails are hermaphroditic, becoming sexually mature in just 12 to 18 months. They climb about 1 foot out of the water to lay egg clutches of up to 5,000 eggs which hatch in 11-21 days. Females may lay eggs every 5-14 days. Apple snails are omnivorous, preferring submerged aquatic vegetation, which destroys native fish habitats, but will eat decaying organic matter. They have become a menace to Louisiana’s crawfish industry.
Apple snails’ egg clutches carry a neurotoxin, and the snails themselves carry parasites such as rat lungworm disease. Crushing egg clutches is the safest way to prevent hatchlings from joining the environment.
A natural predator, the limpkin (Aramus guarauna), tropical wetland birds who have also been found in Florida, are now seen in Louisiana. Racoons and alligators have also been observed eating apple snails, but their consumption does not outpace the snails’ reproduction. Limpkins were spotted in St. John the Baptist Parish in 2022 by Wisner.
Wisner first spotted evidence of feral hogs on its property in Fourchon, Lafourche Parish, on property leased to the Greater Lafourche Port Commission (the Port). The Port hired a trapper who trapped the area until 2023. In 2021 evidence of the hogs was observed in Bayou Segnette and camp owners began to complain of hogs coming onto their lease areas. Feral hogs are in all 64 of Louisiana’s parishes.
USDA’s APHIS (Animal and Plant Health Inspection Service) feral hog eradication program performs aerial gunning and ground trapping for landowner owners at no cost to the landowner. Wisner coordinated with its neighbors, Elmer’s Island Refuge, the Port, and the Jean Lafitte National Historical Park and Preserve to allow aerial gunning and ground trapping.
In 2025, Wisner assisted USDA’s APHIS program in successfully writing a $270,000 grant to the Barataria-Terrebonne National Estuary Program’s Bi-Partisan Infrastructure Law grant program to expand its aerial gunning and ground trapping program in the Barataria Estuary. Wisner is recruiting other landowners to join them in the eradication efforts. Louisiana’s Department of Wildlife and Fisheries estimates that a 70-75% reduction in the population keeps the population static.
A domestic pig can become feral within 30 days: growing tusk, thick fur, and becoming aggressive. The females mature at 6 months and can have up to two litters of 4-10 piglets per litter each year. They are highly adaptive and omnivorous. They root for food, destroying wetlands and increasing erosion by gobbling up the roots that hold everything together. They also eat the eggs and young of every species, decimating endangered and threatened species and nesting and migratory birds. The pigs carry up to 34 different diseases, many which can be transmitted to humans, as well as contaminate waterways with their waste.
Louisiana considers them to be nuisance quadrupeds that can be hunted year-round at night and during the day with a valid hunting license and landowner permission. Wisner’s hunters are asked to shoot hogs before game.
Feral Swine: Managing an Invasive Species | Animal and Plant Health Inspection Service
Wisner has trappers who participate in CWPPRA’s Coastwide Nutria Control Program. The program’s goal is to eradicate 400,000 nutria a year by paying trappers per tail. From 2002-2006, trappers received $4.00 per tail; from 2006-2019, trappers received $5.00 per tail; and from 2019-present, trappers received $6.00 per tail. Since the program began in 2002, the number of acres damaged per year by nutria has gone from 100,000 acres to as low as 4,181 acres in 2014.
Nutria are another South American invasive species, brought here between 1889-1930 as part of the fur trade. They cause significant damage to coastal marshes and wetlands by their voracious consumption of plant roots, rhizomes, and tubers, and burrowing into levees and marshes. The damaged areas will quickly convert to water when there are no plant root systems to hold the sediment together. They are semi-aquatic mammals. Males reach maturity between 4-9 months and females reach maturity between 3-9 months. The gestation period is 130 days, in one year, a female nutria can produce 2 litters with 1-13 young in each litter and be pregnant with a third in one year.
Wisner’s waterways become clogged by this floating, flowering plant from South America. Orgininally introduced in Louisiana for the Cotton Exposition in 1903, this plant has a dual personality. It is a top-selling aquatic garden plant and its beautiful blooms mask its menace to ponds, lakes and bayous. Its dense floating mats obstruct navigation and block sunlight, killing submerged vegetation. Decaying vegetation reduces oxygen levels and degrades the habitat for all other life forms. The dense, fibrous, branching roots can extend 2-3 feet beneath each plant, and have a rhizome to start a new plant.
The plant reproduces in one of three ways: from its flowers’ seeds, from a severed piece of a plant that floats off to start a new colony, or from its rhizome. The unchecked growth becomes more problematic as the year progresses. Freezes knock them down but do not eradicate them. The State no longer sprays the mats. Several groups have applied for BTNEP grants to study methods to either harvest and use the plant’s fibers or to eradicate its growth. Wisner has offered its property to different scientists to find eco-friendly removal methods.
NIS Species Info - Water Hyacinth