October 2020
TPW Commission Meeting to Consider Proposed Exotic Aquatic Species Rule Changes

Texas Parks and Wildlife Department is proposing to make changes to the rules for exotic fish, shellfish, and aquatic plants. These changes will reorganize the rules for accessibility, and address the changing needs of the regulated community, including creating new allowances for the removal and disposal of certain prohibited aquatic invasive species found on public and private waterfront properties.

Some non-native fish, shellfish, and aquatic plants are classified as exotic, harmful or potentially harmful species by the state of Texas. It is unlawful to import, possess, transport, export, sell, or introduce these exotics unless authorized by the appropriate TPWD permits. These restrictions are important to prevent accidental spread of invasive species. However, it can be difficult and confusing for land and waterfront owners to lawfully treat, or remove prohibited exotic species from their property. For example, the physical removal of prohibited exotic species, like Giant Salvinia (Salvinia molesta) or Hydrilla (Hydrilla verticillata), from public or private waterfront property requires an Exotic Aquatic Vegetation Removal Permit and treatment proposal. If the proposed changes are adopted, land owners would no longer need a permit to remove prohibited exotic plants from public or private waters, as long as they are being removed for the purpose of disposal, and all removed plant material is securely contained or left to desiccate/decay on the property before disposal. A nuisance aquatic vegetation treatment proposal would still be required for public waters to aid TPWD in protecting aquatic habitats.

There are currently no permits or options available for individuals to remove or dispose of zebra mussels (Dreissena polymorpha) or apple snails (Pomacea maculata). The only current options are to scrape the mussels into the water, remove adult apple snails from their shell, or smash apple snail and their eggs on site. It is unlawfull to remove or transport zebra mussels or whole apple snails/eggs cases. If the rules are adopted, landowners will be able to remove prohibited exotic plants, zebra mussels, and apple snails in accordance with measures to prevent spread. If you would like to learn more about TPWD exotic species regulations click here.

These rule changes have not yet been adopted. The TPW Commission is meeting November 9th-10th to consider adoption of these proposed changes. To review the proposed rule changes and provide public comment, visit: TPWD Public Comment Page.

*Stay tuned for the follow up article in the November 2020 iWire.

board meeting
 Image credits: Kylee N Kleiner, TRIES


Spotting A Spotted Jelly

Australian spotted jellyfish (Phyllorhiza punctata) have been spotted at least three times along the coast of North Carolina, between Wrightsville Beach and Beaufort. Residents are being encouraged to catch the invasive jellyfish, and place them on land where they will die. These invasive jellies are present in the Pacific coast and Atlantic coast, but have been seen in northern parts of the Gulf of Mexico since 2000. Although these jellyfish are predominantly seen along the coasts of Mississippi, it is likely that they are present in Texas Gulf water.

Australian spotted jellyfish are rounded and somewhat flattened gelatinous bells that are clear, with a brownish tint. They have multiple reflective areas along the bell that look like white spots. The spotted jellyfish averages 18-20 inches in bell diameter. They tend to aggregate in near-shore waters, surviving on larval fishes and planktonic invertebrate. They can negatively impact the populations of fish such as red drum (Sciaenops ocellatus) or spotted seatrout (Cynoscion nebulosus), can clog nets resulting in decreased catch in the shrimp industry, and can negatively impact zooplankton levels. They have a mild sting but their venom is not toxic to humans.

Vigilant eyes on ocean waters, and active sighting reports can help estimate how many Australian spotted jellyfish are within the Gulf of Mexico so further measures can be taken to eradicate this invasive animal before they become a big problem in Texas waters. If you think you have seen an Australian spotted jellyfish, please take a picture, record your location, and email: invasives@shsu.edu

For more information: Australian spotted jellyfish.

Australian spotted jellyfish
 Australian spotted jellyfish (Phyllorhiza punctata). Credit: Trish Murphey, NC Department of Environment ad Natural Resources, Bugwood.org
Smack of Australian spotted jellyfish
Smack of Australian spotted jellyfish. Credit: Harriet Perry, Gulf Coast Research Laboratory, Bugwood.org

It’s a Hog? It’s a Boar? It’s… Super Pig?

Feral hogs (Sus scrofa) have a secure seat on the list of most problematic invasive species in Texas. The Texas population alone surpasses 1.5 million, with approximately 9 million spanning 35 states. Mature feral hogs can grow up to 36 inches high at the shoulder and weigh over 400 pounds. Their nocturnal rooting behavior disrupts vegetation and soil, leaving trademark ruts behind. The increased number of lumbering bodies and veracious appetites are endangering ground nesting birds and animals. They are major nest predators of threatened and endangered sea turtles. They also can carry several diseases and parasites that can be transmitted to livestock and wildlife. In 2019, the annual loss to agriculture in Texas due to feral pig damages was estimated at $118.8 million.

Hogs (Suidae) were first introduced to Texas over 300 years ago by explorers as a food source. Since then, these hogs have been domesticated and bred to be fertile all year round. When a domestic hog escapes or is released, it will quickly become feral. Each generation of offspring will lose the domestic traits and grow sharp tusks, which are usually cut off piglets by farmers. In the 1930s, the European wild boar was introduced by ranchers and sportsmen for hunting. European boar and feral hogs are mating, resulting in a European-feral crossbreed, also called “super pigs”, that retain the best traits from each. They remain fertile all year round, capable of producing multiple droves a year, each with an average litter of 10 piglets. They have tough hairy hide, are highly intelligent, and can adapt quickly. Because of crossbreeding, there are very few true European boars remaining in Texas.

Feral hog hunting is legal all year round without a permit. Transportation and release of live feral hogs can exacerbate the situation and is unlawful, unless in compliance with Texas Animal Health Commission (TAHC) regulations. TPWD Hunting Regulations. Authorities utilize multiple methods to reduce the population of feral hogs, including traps and aerial gunning. There is a lot of controversy about how various method may alter feral hog behavior and spread them to areas not yet infiltrated. Texas estimates indicate that with current control methods, annual population reduction reaches 29%. A continuous 66-70% population reduction is necessary to prevent a population boom. There may be 30-50 wild feral in your yard preventing your kids from playing outside for 3-5 minutes, but vigorous efforts are being made.

*Hunting for native Javelinas (Peccary), which are smaller than feral hogs with a square build, distinct lighter collar of fur and no tail, and not problematic, is restricted to hunting season and requires a license.

For more information: Ecology and Management of Wild Pigs.

Sus scrofa (feral type)
Feral hog (Sus scrofa).  Credit: Florida Fish and Wildlife Conservation Commission, Bugwood.org
Feral pig damage
Feral pig damage. Credit: USDA Wildlife Services.

Javelins (Peccary). Credit: USDA Wildlife Services.

Hydrilla is Back in Town

Texas Parks and Wildlife Department has found hydrilla (Hydrilla verticillata) on Lake Conroe for the first time in ten years. Hydrilla was found on a one-tenth acre stretch of the Caney Creek arm of Lake Conroe, which spans over 20,000 acres. TPWD and the San Jacinto River Authority plan to treat the small hydrilla colony, and monitor for potential future hydrilla growth by implementing a combined approach of targeted herbicide applications, and stocking the lake with triploid grass carp (Ctenopharyngodon idella). Targeted treatments with a prescribed herbicide can illuminate visible patches of hydrilla, while allowing surrounding native plants to flourish. Triploid grass carp eat the part of hydrilla and certain other invasive aquatic vegetation floating below the water’s surface. Five hundred of these fish will be stocked in order to restore the carp population to a more desirable number, similar to the population status in 2019. The lake was first stocked in 2008, since then a portion of the population was lost to mortality.

Hydrilla colonies form dense underwater stands that outcompete native submerged aquatic vegetation, promote mosquito habitat, raise water pH and temperature, and lower dissolved oxygen. While the number of small fish can increase due to additional habitat created by the mates, large fish populations often decrease. Hydrilla infestations can also block intakes and impede water flow, directly affecting power generation and agricultural irrigation. It is unlawful to remove hydrilla without a TPWD permit. An additional permit is required to possess or transport triploid grass carp, see Texas Administrative Code. Public and private waterfront owners interested in using triploid grass carp to treat nuisance vegetation must obtain a permit from TPWD. The first step for landowners and TPWD is to identify the aquatic vegetation present, and determination if triploid grass carp can be an effective control.

Hydrilla (Hydrilla verticillata)
Hydrilla (Hydrilla verticillata). Credit: Vic Ramey, University of Florida.
Dense underwater stands of hydrilla
Dense underwater stands of hydrilla. Credit: Michael Frank, Galileo Group Inc., Bugwood.org

Angling for Invasive Species

Researchers at the University of Washington are using data from fishing technology to track more than fish. Data collected from iBobber by ReelSonar, a fish finder app that syncs with a smart device to show the location of fish, has allowed researchers to model the movement of Anglers, fisherman that catch exotic fish, and predict the possible spread of invasive species. Researchers are focused on Anglers because they use an extensive range of gear and have the greatest potential to accidently move a wide range of aquatic hitchhikers that attach to boats, motors, and fishing gear.

Previous studies relied on Anglers to voluntarily fill out forms and log each fishing location visited during each trip. With passive data collected from ReelSonar all that information is logged automatically. This requires no additional steps from the fisherman. With the data collected, researchers can map the locations of predominant fishing sites, the route taken to get from one site to another, and the time laps between trips. Each aquatic invasive has a different survival rate once out of water. Knowing the time between trips can determine the likelihood of unintentional invasive species transfer. Anglers regularly move between different fishing locations within one trip. Knowing popular fishing locations and common routes of travel could allow the Fish and Wildlife Department, and other park services to set up mandatory watercraft inspections, targeted educational programs, and even station dogs trained in sniffing out invasive species, resulting in a more proactive and productive use of resources.

iBobber technology syncs with an angler's smart device.
iBobber technology syncs with an angler's smart device.  Credit: iBobber


North American Invasive Species Management Association Training Webinars

The program is designed to provide the education needed for professionals and students who are managing or learning to manage invasive species. The courses include the most current invasive species identification, control and management techniques, and how to comply with local and federal regulations.

Participants may register and enroll at any time and will receive a certificate of invasive species management from NAISMA upon completion of the program.

All live webinars are open to the public. Recorded webinars are available to members of NAISMA.

NAISMA 2020 Webinar Schedule:

  • November 18 - The ABCs of Invasive Species Organizations and How They Work Together - REGISTER
  • December 16 - The Invasive Species Data Mobilization Campaign - REGISTER


Young Naturalists Children's Program

This program aims to teach children about nature and wildlife with Ranger Holly from Guadalupe River State Park. It is offered ONLINE via Zoom by TPWD and Mammen Family Public Library. Registration is free, but availability is limited.

  • November 11, 2020, 4:00pm – 5:00pm Central time - REGISTER
  • December 9, 2020, 4:00pm – 5:00pm Central time - REGISTER
Mammen Family Public Library

Fate Bell's Shelter Pictograph and Canyon Walking Tour

For the month of November, the Seminole Canyon State Park will be offering guided-only hikes to go down into the canyon to view pictographs (ancient drawings). Limited to ten participants per tour.

Multiple dates available between November 1 - 29, 2020. Tours are offered Wednesday through Sunday, at 10:00am and 3:00pm.

Online registration required.

Fate Bell Shelter Rock Art- TPWD
Fate Bell Shelter Rock Art in Seminole Canyon State Park. Credit: TPWD.

Invasive Spotlight:
Apple Snail
(Pomacea maculataspp.)

Apple snails (Pomacea maculata) are large aquatic snails found in slow-moving, shallow freshwater habitats including streams, bayous, ponds, irrigation canals and rice field. They have a globular-shaped shell that grows between 2-3 inches, but can get as large as 6 inches. The shell color can vary between black, brown, green, or yellow, and sometimes bare banded patterns. Bright reddish-pink eggs are found in groupings of 200-600, and are laid above water level near the water’s edge. Eggs are predominantly found on aquatic vegetation, but are also found on man-made structures, tree branches, trunks and cypress knees. The pink coloration is due to high levels of carotenoid components, which make them easier to spot than the submerged adults. Female apple snails can lay egg clutches every 5-14 days. When juveniles hatch, they fall or crawl into the water. Egg cases fade to a white-ish color after the snails have hatched.

The snails reproduce frequently, allowing them to quickly reach high population densities, causing habitat degradation, competition with native snails, devastation of aquatic vegetation, and clogged drainage pipes. During periods of extreme drought, these snails may survive by burrowing. They cause significant damage to rice crops in Asia, although damage to rice crops in Texas has not yet been documented. Populations of apple snails have tested positive for the rat lungworm nematode, Angiostongylus cantonensis, in New Orleans, LA, but there have been no cases of human infections.

Apple snails are native to South America. In the 1980s, they were introduction into the U.S., and have since spread across southeastern states and 22 Texas counties. U.S. introduction was likely caused by persons in the tropical pet industry, aquarium dumping, or pet snail release. Management options for apple snails are limited. Chemical treatments can negatively impact native aquatic plants, animals, and drinking water. The only known terrestrial predator in the U.S. is the raccoon, but predation alone is not an effective control. Management of aquatic vegetation in apple snail-infested areas has the potential to exacerbate their impacts, and should be undertaken with care. Physical removal and destruction of eggs can help to reduce numbers. However, the removal of adult apple snails from any habitat is prohibited in Texas to prevent accidental spread. Citizens can remove pink egg masses when found. They should not be scraped into the water to drown them. Instead, TPWD recommends they should be scrapped off and crushed completely.

If you see adults or eggs, please REPORT IT here or send a photo and location information to aquaticinvasives@tpwd.texas.org. Read more about apple snails at tsusinvasives.org or texasinvasives.org


Adult Apple Snail
Apple Snail Eggs
TOP: Apple snail (Pomacea maculata). BOTTOM: Apple snail eggs. Credit: Matthew McClure, TISI, Lamar State College-Orange Location: Armand Bayou, Pasadena, TX.
apple snails (Pomacea maculata)
Apple Snails eating Soft-stemmed Rush (Juncus effusus). Credit: Jess Van Dyke, Snail Busters, LLC, Bugwood.org


Giant Salvinia and Zebra Mussel Watch

Giant Salvinia (Salvinia molesta) has returned to Lake Athens and Lake Gilmer, Tyler, Texas. TPWD confirmed the resurgence of the aquatic invasive fern following surveys along the water bodies last month. Giant Salvinia was also found at the boat ramps of Lake Gilmer. The Texas Parks and Wildlife Department plan to conduct a more comprehensive survey of Lake Gilmer. All Salvinia discovered during the survey was treated or removed according to TPWD protocol.

TPWD has upgraded the Zebra Mussel (Dreissena polymorpha) status at the Richland Chambers Reservoir, southeast of Dallas, from “positive” to “infested” after surveys late this summer provided evidence that the invasive nascence is reproducing and beginning to spread. Grapevine Lake, near Grapevine, and O.H. Ivie Lake, east of San Angelo, TX, were also designated as fully “infested" this summer.

Don’t forget to remove all plants and debris from your boats, trailers and gear, and drain all water from the boat, buckets and equipment. Cleaning all water recreation equipment thoroughly is important. Zebra mussel larvae are very small and can hitch a ride in undrained water. Even the smallest piece of salvinia accidently introduced can cause a new infestation. Remember: Clean, Drain, Dry and Stop the Spread.

mussel signal KNK
 Credit: Kylee N Kleiner, TRIES

More News

Cute Goats Are Helping with Yard Work at Houston Arboretum
Follow up to September 2020 iWire article “Goats for Hire in Houston”: More than 100 goats from a vegetation management company chewed their way through 1.5 acres of the Houston Arboretum earlier this month. reformaustin.org

Kingwood Area Hosts Pilot Program to Remove Kudzu Vines
The city of Houston has begun a pilot program to remove the invasive Kudzu vines (Pueraria montana) in the Kingwood area. communityimpact.com

The Paradox of the Burmese Python
In Florida, scientists want to kill the Burmese Python (Python bivittatus). In Southeast Asia, they want to save it. The story of how they are working together. newrepublic.com

Steam Cleaning the Port of Tacoma to Eradicate Invasive Snail
Washington State University is working with local authorities and the Washington State Department of Agriculture to eradicate the invasive Mediterranean vineyard snail (Cernuella virgata) in the port of Tacoma using steam. news.wsu.edu

NOAA Report Reveals Condition of Natural And Cultural Resources of Papahānaumokuākea, Hawaii
NOAA has published a report that accumulates 10 years of research and includes information on the status and trends of living resources, habitats, ocean conditions, maritime and cultural archaeological resources, and the human activities and natural events that affect them. phys.org

Supergene Discovery Leads to New Knowledge of Fire Ants
Resent research on the supergene in fire ant (Solenopsis invicta) colonies determines whether young queen ants will leave their birth colony to start their own new colony or if they will join one with multiple queens. phys.org

AAnts Adapt Tool Use to Avoid Drowning
Researchers observed black imported fire ants (Solenopsis richteri) using sand to draw liquid food out of containers when faced with the risk of drowning. sciencedaily.com

Insights into a Tiny Insect That Causes Big Damage
The invasive western flower thrips (Frankliniella occidentalis) causes billions of dollars of damage on food, fiber and ornamental crops each year. Scientists now have a complete genetic blueprint to help them better understand the pest and to find ways to control it. Research paper. phys.org news article.

International News

Invasional Meltdown in Multi-Species Plant Communities
A new experiment addresses competition among plants in communities composed of several plant species, both alien and native. The results pinpoint one major reason for invasion success and subsequent invasional meltdown to soil microbes. phys.org

Crayfish 'Trapping' Fails to Control Invasive Species
Concerns that American signal crayfish (Pacifastacus leniusculus) are wiping out other species of crayfish across Europe, including the endangered white-clawed crayfish (Austropotamobius pallipes). Crayfish 'trapping' is not helping to control the invasive species population. Research paper. sciencedaily.com news article.

Researchers Complete World First Wasp Genome Project
New Zealand researchers have sequenced the genome of three wasps (Vespidae), two of which are invasive wasps in New Zealand, paving the way for new methods of control for these significant pests. phys.org

Australian Carp Virus Plan 'Dead in the Water'
Researchers suggest plans to release a virus to reduce numbers of invasive Common Carp (Cyprinus carpio) in Australia are unlikely to work long term and the plans should be dropped. Research paper. sciencedaily.com news article.

Researchers Study the Invasive Frog's Role in Galapagos Food Web
Researchers examine the stomach contents of Fowler's snouted treefrog (Scinax quinquefasciatus) in order to determine the interactions of this invasive frog with the primarily endemic fauna on Galápagos. phys.org

Alien Species to Increase by 36% Worldwide by 2050
The number of alien or non-native species is expected to increase globally by 36% by the middle of this century, compared to 2005, finds new research by an international team involving UCL, and many of those could end up becoming invasive.  Research paper. sciencedaily.com news article.


If you would like to highlight a successful invasive species project or nominate a special person to be highlighted in an upcoming iWire, please send the details to iwire@texasinvasives.org.

Citizen Scientists Spotlight
Successful Apple Snail Workday, All Thanks to the Employees of Laporte Parks System

LaPorte Parks System partnered with Texas Invasive Species Institute (TISI) last month to host an Apple Snail Workday in LaPorte, TX. The clearing effort was facilitated by Ronnie White, whose goal was to clear away invasive snails from the city’s water bodies. The park’s employees were trained to identify and destroy adult Apple Snails and eggs, and informed on how to follow proper TPWD invasive species removal protocols.

The assembled team prepared for the long day by steping into their water waiters and/or rain boots, and slipping on a pair of rubber gloves (in order to protect against the parasites transmitted by many different types of mollusks). The adult snails were mostly located and fished out of the water’s edge with nets or removed by hand from drainage pipes. The eggs were scrapped from various surfaces surrounding the area, such as concrete walls, water vegetation, and tree trunks along the water’s edge. After over 7 hours of sweating and vigilant searching, the soggy team assessed their haul.

With the concerted efforts of 18
LaPorte Park System employees and Ashley Morgan-Olvera, they were able to clear over 150 lbs. of adult apple snails, and thousands of eggs from one sports complex and one residential park in LaPorte, TX. Special thanks to those hardworking employees: Saul Banda, Brian Bedford, Gilbert Bayer, Eric Flores, Travis Clawson, Chris Gaitan, Michael Grimes, Vance Liles, Shaun Lundy, Stephen Macon, Hunter McCraig, Chris Muska, Gainus Scott, August Smith, Joshua Smith, Caleb Stutes, Chris Wells, and their supervisor Scott Bradley, who kindly provided lunch for everyone. Visit the City of La Porte Facebook page, under Parks and Recreation, to see the crew in action.

*All adult Apple snails and eggs were smashed on site and removed according to TPWD Apple Snail regulations.


Apple snails in bucket- LaPorte
Bucket full of apple snails removed from a residential park in LaPorte, TX. Credit: Ashley Morgan-Olvera.


Sentinel Pest Network and Invaders of Texas Workshops

Invaders of Texas workshops train volunteers to detect and report invasive species as citizen scientists. Workshops, which are free, are designed to introduce participants to invasive species and the problems they cause, cover aspects of invasive species management, and teach identification of local invasive plants, and to train participants to report invasive plants using the TX Invaders mobile application. The workshop is 7 hours long (usually on a Saturday, but scheduling is arranged with each individual host group). The workshop satisfies Master Naturalist training requirements.

Sentinel Pest Network workshops serve to increase the awareness and early detection of a set of particularly important invasive species, to help prevent their spread into Texas or their further spread within Texas. Participants learn to identify species such as the Emerald Ash Borer, Cactus Moth, Asian Longhorned Beetle, and other pests of regulatory significance, and to report them. The workshop is 3.5 hours long. The workshop satisfies Master Naturalist training requirements.

Upcoming Workshops:

--None scheduled--

For more information or to register to attend a free workshop, please visit the Workshop Page.