Calling them the densest he’s ever seen, LSU AgCenter entomologist Blake Wilson was startled to search out invasive apple snail egg lots in St. James Parish, however mentioned preventative measures, and just a little assist from Mom Nature, can mitigate the unfold and potential injury to the crawfish business.
Wilson, who makes a speciality of agriculture pest administration analysis, had beforehand encountered excessive concentrations of apple snails, or Pomacea maculata, in Calcasieu, Vermillion and Lafayette parishes, with smaller concentrations in Cameron and Jefferson Davis.
Final week he obtained a name from a involved crawfish farmer from St. James, who found the unmistakable vivid, pink eggs. Wilson believes extreme climate and flooding during the last 12 months could have contributed to the unfold.
“It’s likely they may have shown up on new farms following the hurricanes last year,” Wilson mentioned. “Any type of flooding can create an easy way for them to get into isolated ponds.”
At present, Wilson estimates that fewer than 3,000 of Louisiana’s estimated 200,000 acres of crawfish farms have been impacted, however these farms have been hit arduous. In response to Wilson, every apple snail egg mass can comprise a whole lot of eggs, with a feminine producing them each week to 10 days in the summertime months.
“They’re catching half the normal crawfish due to mature snails both clogging trap entrances and consuming the bait,” Wilson mentioned. “In some fields, there has been more than a 50% reduction in the overall crawfish catch.”
Launched to the Louisiana ecosystem round 2016, apple snails have been bought in pet shops for aquariums as “Mystery Snails,” “Island Snails,” and “Giant Apple Snails.” The primary sighting within the wild in Louisiana was in a swamp close to Schriever, about 12 miles north of Houma, in Terrebonne Parish. Whether or not careless or intentional, a pet proprietor was the seemingly trigger.
Jacoby Carter, a wildlife ecologist on the U.S. Geological Survey Wetland and Aquatic Analysis Middle in Lafayette, mentioned along with crawfish ponds, apple snails current an issue in pure techniques. They eat native, submerged, aquatic vegetation, eliminating meals and habitat for geese and different species, whereas additionally serving to invasive aquatic plant species by eradicating the competitors.
Carter mentioned though younger snails have a mess of predators, people ought to stay cautious when encountering the eggs, and undoubtedly shouldn’t eat the adults.
“The snail hatchlings are a millimeter wide at most, so they are food sources for fish, turtles and have even been found in the stomachs of frogs,” Carter mentioned. “But, in the egg stage, they emit toxins that can irritate human skin, and the adults carry lung worm, which can make people sick.”
Snail egg lots develop a couple of inches above the water. A great way to forestall eggs from hatching is to submerge them in water. (Blake Wilson/LSU AgCenter)
Wilson mentioned as a result of many farmers dump crawfish within the late spring to inventory their ponds for the subsequent cycle, it is a essential time to ensure to not inadvertently introduce snails to the ponds throughout that course of.
“A main point I’d like to emphasize is not to move boats and equipment from infested bodies of water to those that are not infested,” Wilson mentioned. “Anything near the surface of the water can get an egg mass on it and they can be introduced that way.”
Carter mentioned the best strategy to destroy apple snail egg lots within the early, bright-pink stage is to, whereas carrying gloves, fastidiously scrape them into the water the place they are going to be unable to outlive and hatch. As soon as the hatchlings begin to develop shells and turn out to be white, it’s finest to crush them.
“At that point, you’re just helping them along with the maturing process if you move them to the water,” Carter mentioned.
Wilson provides that mature apple snails should not significantly adept at shifting throughout land with out assistance from pure flooding occurrences. He encourages crawfish farmers to make use of properly water for managed flooding of their ponds, which many do. He mentioned to this point that is the very best methodology to forestall additional unfold.
“We’re hoping to identify a management strategy that’s compatible with crawfish,” Wilson mentioned. “Draining to low water can be effective in getting rid of the snails, but it’s also detrimental to crawfish.”
Carter provides that apple snails have the power to burrow into the mud and wait out dry spells, with some surviving for greater than six months doing so.
“One possible mitigation method is once crawfish ponds are drained to till them after they have dried out,” Carter mentioned.
Chemical management choices could be a future answer, Wilson believes, however these include their very own caveats.
“One shows a little promise, but finding a chemical that’s detrimental to snails, yet safe for crawfish is a challenge,” Wilson mentioned. “Plus, it could be a hard sell to consumers.”
Wilson websites as his greatest concern apple snails persevering with to unfold into new farms and affecting your complete crawfish production business. However he mentioned that may be a worst-case situation that may be prevented.
“Eventually, we might be able to identify a solution, but it’s not going to be a silver bullet,” Wilson mentioned. “The best method of prevention is for farmers to remain aware, use controlled flooding with well water when possible and to clean their equipment thoroughly before transferring it from pond to pond.”
Supply: Louisiana State College, Ag Middle, which is solely liable for the data supplied and is wholly owned by the supply. Informa Enterprise Media and all its subsidiaries should not liable for any of the content material contained on this info asset.