Have you noticed fewer small lizards lately? What is to be done about this invasion of foreign species? Hint to Herr Trump's supporters: No, a wall would not help.
One looks innocuous and kind of drab. Boasting needle-sharp spines, the other appears as fearsome as its name implies.
Cuban treefrogs and lionfish top the list of most destructive invasive species threatening Northeast Florida’s native ecosystem while also posing a health risk to people and pets, state wildlife biologists and university researchers say.
Florida is home to at least 500 different non-native fish and wildlife species. At least 150 are reproducing. Among them, lionfish and Cuban treefrogs are classified invasive species because they decimate native species, jeopardize human health and safety or damage the economy, according to the Florida Fish and Wildlife Conservation Commission.
Ancedotal evidence indicates lionfish arrived in the coastal waters of Northeast Florida about 20 to 25 years ago. Cuban treefrogs — entrenched on land in Duval, Clay, Nassau and St. Johns counties — showed up in the region about 27 years ago.
Scientists say both species appear to be thriving although their exact population is unknown. But it’s clear both are more than just annoying intruders. Each upset the biodiversity essential to a healthy environment, research shows.
Predators as well as cannibals, lionfish and Cuban treefrogs are prolific breeders that devour native fish and animals as well as compete for food with them. People risk a painful sting or allergy-like reaction if careless when handling either species.
Lionfish also threaten recreational and commercial saltwater fish species prized by resident and out-of-state fishermen who pump millions of dollars annually into Florida’s economy.
The spread of non-native wildlife — jumping to 87 species this year from 56 in 2008 — is one of the major factors straining the health of the St. Johns River. Lionfish and Cuban treefrogs are of particular concern, according to the 2018 State of the Lower St. Johns River Basin Report.
The report released Sept. 14 notes “once an invasive species gets here, it’s here to stay,” because it’s too expensive and too difficult to remove once entrenched in the ecosystem. Researchers from the University of North Florida, Jacksonville University and Florida Southern College in Lakeland compiled and analyzed the data for the report.
LIONFISH THREAT
Armed with venomous spines and voracious appetites, lionfish are gluttons of the sea. The invasive species also has a bad attitude belied by its colorful appearance, scientists say.
“They are very prevalent off shore in the artificial and deep reefs ... mainly offshore in the 70- to 110-foot [deep] range is where we typically find them,” said Eric G. Johnson, a researcher and UNF associate professor of biology who is respected as a lionfish expert, especially regarding Northeast Florida coastal waters.
“We’ve not yet found any in the St. Johns River here or the Intracoastal Waterway, or any of those areas,” said Johnson, who has a doctorate degree in marine science.
However, lionfish can tolerate estuarine and brackish habitats of fairly low salinity. If the river’s salinity increases, it’s conceivable lionfish might show up at some point. Johnson said the ongoing river dredging will cause changes in the salinity wedge of the system’s hydrodynamics.
“But I don’t envision seeing a lot of lionfish in the river. They simply don’t like shallow water very much. They get beat around so for all the things lionfish are, they’re not very hydrodynamic fish. If they’re getting wave action, they’re basically rolling around,” Johnson said.
Johnson will be among marine scientists from across the nation along with state and federal wildlife biologists presenting and discussing their research this week during the three-day 2018 Lionfish Summit. Hosted by the Florida Fish and Wildlife Conservation Commission, the summit begins Tuesday in Cocoa Beach.
He will summarize his research findings, “Understanding the Biology and Ecology of Invasive Lionfish: Insights from Northeastern Florida ” on Wednesday during a session focusing on lionfish control efforts, research and monitoring.
The summit will examine the effectiveness of past research, management and outreach efforts to control lionfish in Florida coastal waters. Johnson and other presenters will provide updates regarding their research.
Johnson, who previously worked with invasive species at the Smithsonian, has researched lionfish since coming to UNF in 2011. Back then, no one really had been looking at what lionfish were doing off the coast of Northeast Florida, he said
“Honestly, we were one of the first places colonized. The invasion, the best that we know, started just north of Miami,” he said. There’s no smoking gun, but genetic work and anecdotal reports indicate many lionfish got here through shipping channels after being released when they got too big for an aquarium, he said.
Lionfish are a top level predator similar to grouper and snapper, which inhabit the reefs. Some are as big as 20- to 24-inches long and can eat a fish half their body size.
“They are voracious. They have fatty liver. We open up some of these fish and they’re not healthy because they are essentially are obese. ... They basically gorge themselves,” Johnson said.
Johnson said lionfish feed on about 25 different species of fish including some prized by anglers. “We were the first to find that they are eating black sea bass and vermilion snapper, both of those are commercially and recreationally important species here,” he said.
Scientists don’t know the lionfish impact on those populations but they are feeding on those species, he said.
Johnson said lionfish feed on fish that serve important ecologically roles on the reef to keep it healthy.
Lionfish also will eat each other. They also don’t play well with others. And don’t back down because they have no natural predators,
“If you go out to a reef, lionfish act like they own the place. They can see their seven best friends get speared and put in a bag and they’re still just sitting there, like, ‘What are you going to do about it?’ ” Johnson said.
The summit’s goal is to educate the public, identify ongoing efforts to remove the lionfish and identify research gaps in control efforts.
TREEFROG INVASION
Larry Figart routinely gets calls about Cuban treefrogs because he’s a urban forestry extension agent at the Duval County Extension Office of the University of Florida Institute of Food and Agricultural Sciences.
About five years ago, the treefrogs started showing up in the yard of his Jacksonville home, he said.
Hurricane Irma triggered a mini-invasion. Unbeknownst to Figart, several of the treefrogs took refuge inside an angel lawn ornament he brought inside their laundry room to prevent it from being damaged in the storm.
“All of a sudden, there are five stinking Cuban treefrogs hopping around the laundry room,” said Figart, who quickly “dispatched them.” All but one, he said.
“My wife goes to do laundry and one of those five had ended up in the washing machine. He was washed to death,” Figart said.
Figart said the ornament was only about the size of a flower vase yet the treefrogs crammed inside it with no apparent problem. The species is adept at getting into small places.
“They are all over the place,” Figart said.
Growing about as big as a man’s fist, Cuban treefrogs secrete mucus through their skin that can burn a person’s eyes, and trigger an allergic reaction including sneezing, stuffy or runny nose and a rash. Pets can get sick from eating or licking the treefrogs, scientists say.
The invaders devour native species such as green and squirrel treefrogs reducing or eliminating those populations in some areas. The treefrogs also eat small lizards, snakes and their own young.
The amphibians can find their way into toilets and clog plumbing. They will short circuit home electrical boxes, and lay their eggs in bird baths and fish ponds fouling the water. In addition, Cuban treefrog tadpoles beat out native tadpoles for food and space, according to scientists.
“Although large numbers are killed during freezes at the northern extent of their range, populations are apparently able to rebound quickly,” said Carli Segelson, a Fish and Wildlife Commission spokeswoman.
COMBAT STRATEGIES
Florida’s invasive species problems, scientists say, have increased in frequency and severity over the past decade.
The Fish and Wildlife Commission currently spends at least $3 million annually to regulate, prevent and remove those species.
It’s illegal to release lionfish, Cuban treefrogs and other non-native fish and animals into Florida habitats. Nonetheless, people do it. Invasive species also infiltrate the state’s ecosystem as a result of illegal importation, escaping from collectors, as unintentional stowaways on ships or aircraft and by being carried by storms.
Last Thursday, , the state Fish and Wildlife Commission authorized new strategies to combat the introduction and spread of those animals.
“Actions we take today can prevent other species from becoming established and help avoid problems similar to the ones caused by Burmese python,” said Kipp Frohlich, director of the commission’s Division of Habitat and Species Conservation.
The commission voted to overhaul state rules relating to non-native species. It also authorized Eric Sutton, agency executive director, and commission Vice Chairman Robert Spottswood to work on a temporary executive order to limit importation of potentially high-risk injurious species. That measure will serve as a stopgap while commission staff develop proposed permanent rules.
“It costs much less to prevent a species from becoming established than it does to control them once they are here,” said Commissioner Joshua Kellam, adding the commission needs to “focus on prevention early on to stop the next wave of invasive species.”
The public, meanwhile, can help.
Spearfishing by recreational and commercial divers has proven to be a popular and effective way to control the lionfish population, scientists say.
At least 500,000 lionfish have been removed from coastal Florida waters since the commission launched its harvesting challenge competition in 2014, according to commission data.
The 2018 Lionfish Challenge resulted in a total 28,260 lionfish being removed from Florida waters. Participants competed in recreational, commercial and the new tagged-lionfish category. The tagged category offered prizes up to $5,000 for removing lionfish fitted with an agency tag.
Ron Surrency of Duval County earned the commercial title for removing 5,017 pounds of lionfish — a weight equal to about 5,531 fish. John McCain of Gilchrist County won the recreational title by removing 1,137 lionfish, commission officials said.
Lionfish meat is safe to eat and tasty. The spines containing a venom must be removed first. Johnson said people who eat seafood can help reduce the lionfish population by eating the fish, which is becoming a popular entree.
Scientists say Cuban treefrogs should be humanely killed whenever found.
People can euthanize the treefrogs by putting them in a plastic bag, freezing it for at least 24 hours and then throwing it in the garbage or burying it. The treefrog also can be euthanized by spraying or rubbing it with 20 percent benzocaine — commonly found in sunburn spray or toothache gel.
Teresa Stepzinski: (904) 359-4075
No comments:
Post a Comment