Trapping Tons of Exotic Snails from Wellman Pond

Newly Planted Wellman Pond (9/2007)

 Officially opened on June 1, 2009, Martha Wellman Park provides a lighted, paved loop around a beautiful pond and a perfect place for us to study the Island Apple Snail (Pomacea insularum). Aside from easy access, the gradual slope of the bathymetry, and relatively firm substrate, the burgeoning exotic snail population made this 15-acre (6.1 ha) pond ideal for our work. We also had a great incentive to learn how to control the exotic snails there. As part of the construction of this stormwater treatment pond, a large number of native, emergent plants were placed along the entire shoreline at a cost of $565,000 – - Soft-stem Rush (142,124), Duck Potato (51,227), Arrowhead (22,673) and Pickerelweed (27,468).  After one growing season, 75% of the emergent plants were gone, including all of the Arrowhead and Pickerelweed.

Dense population of Pomacea insularum (2007)

In the fall of 2007, Dr. Sean McGlynn and I began hand-collecting snail eggs and adults in Wellman Pond to save the extensive littoral planting effort funded by the FWCC from the voracious Island Apple Snail. Manually controlling the snails and eggs helped, but clearly something more efficient was needed. In the spring of 2008, we began testing various baiting and trapping methods. We had observed that the exotic snails had excellent chemoreception and could be easily attracted to certain foods. We also noted their proclivity to hide in black plastic (HDPE) flower pots, especially under any broad lip. Finally, we could see that the snail’s mobility was impeded by thin, vertical planes not touching the bottom. Putting this all together, Sean, Lee Ingram, and I devised a trapping system.

Apple Snail Trap in Wellman Pond 

With funding from Blueprint 2000 and Leon County, we deployed 30 Snail Busters’ Apple Snail Traps (patent pending) in Wellman Pond in 2008 and 2009. As we cleaned and baited the traps, we also collected any eggs and adults we observed.  By the end of 2008, we had removed 4.16 tons of snails and 2,135,200 individual eggs! In 2009, the numbers dropped to 0.89 tons of snails and 1,106,400 individual eggs, in response to a much smaller population. This snail control program has stabilized the aquatic plants and the remaining plants were saved. Since these efforts were instituted there has been no subsequent loss of plants in the pond. The surviving plants are growing and reproducing. As Dr. McGlynn put it last fall, “we are seeing a lot of new growth in the pond for the first time in the past two years. This is the best barometer of success.” Posted by Jess Van Dyke

Wellman Pond (9/2009)

The Pomacea Project – - A New Website on Florida Apple Snails

Pomacea paludosa laying eggs

Sometimes, it takes the population decline of a beautiful animal like the Snail Kite (Rostrhamus sociabilis) to draw attention to the importance of, as The Pomacea Project puts it, “less charismatic” species like the native Florida apple snail (Pomacea paludosa). Clearly, the fate of the endangered Snail Kite hinges on the density of its apple snail prey. Patty Valentine-Darby and her husband Dr. Phillip C. Darby, Associate Professor at University of West Florida, were early in understanding that the density of the native apple snail could be used to determine the health of Florida’s aquatic habitats, in general: “Given their relative immobility and sensitivity to changes in water level and plant community structure, apple snails are an excellent indicator of local habitat conditions.”  In the late 90’s, while Phil was conducting his PhD research on P. paludosa, Patty was publishing kite-related papers, such as “Seasonal Patterns of Habitat Use by Snail Kites in Florida.” Since then, Patty and Dr. Phil Darby have made quite a team when it comes to wetlands ecology, specifically concerning the role of the Florida apple snail as a proverbial canary in Florida’s wetland ”coal mine.”  

In 2005, Patty and Phil conceived the idea of creating a website to support other biologists who share the view that Florida apple snails act “a barometer of Florida wetland ecosystem health.” Incorporated in 2008, the Pomacea Project gained its official not-for-profit status this year. Subsequently, The Pomacea Project received funding the National Park Service to “to summarize available information on apple snails, snail kites, and other snail predators, including management recommendations to improve habitat conditions for these species.” Though this document will not be completed until 2012, a website is now available “to provide conservation and management information pertinent to the immediate needs of natural resource managers and the general public.”     

The Pomacea Project website became available this week and already contains a wealth of information on native apple snails, including basic biology, sampling methods, and management issues. The impacts of dry downs, exotic snails, and predators are discussed. There is an online brochure cleverly entitled “The 60-Second Snail – - a primer on apple snails when you only have a minute.” To me, the page with the greatest potential is the “Status and Trends” page, where observations on apple snail densities from eight of the most important apple snail habitats are recorded and updated. They hope to expand this effort to many other wetlands and lakes in the future. All in all, Patty & Phil have done a great job on this new site. They currently do not have funding to support updating and expanding their website. Check it out and, if you can, help them out by making a tax-deductible donation! Posted by Jess Van Dyke  

The Pomacea Project:  

http://www.pomaceaproject.org

Alabama Fights to Protect the Mobile-Tensaw River Delta

I recently spoke with Ben Ricks, District Fisheries Biologist with the Alabama Department of Conservation and Natural Resources (ADCNR), Wildlife and Freshwater Fisheries Division (WFF) about the recent team effort to eradicate exotic apple snails (Pomacea insularum) in Langan Municipal Park Lake and Threemile Creek, Mobile, Alabama (see Recent News). Ben had a positive attitude, “Everything went as well as could be expected given the short period to prepare. We got rid of a bunch of snails!”

While Langan Lake and Threemile Creek are important aquatic assets for Mobile, the urgency of this battle comes from the fact that they are connected to a true ecological gem, the Mobile-Tensaw Delta. Within this National Natural Landmark, more than 300 square miles of marshes, swamps, and bottomlands are now in danger of invasion by the exotic apple snails. This summer, the exotic apple snails were sighted only one mile upstream from one of the most biologically diverse and second largest river deltas in the U.S.

WFF sought assistance and council from a number of experts, volunteer organizations, and public agencies: The City of Mobile, Alabama Department of Environmental Management, Alabama Department of Public Health, Alabama Marine Resources Division, U.S. Fish &Wildlife Service, Environmental Protection Agency, Mobile Baykeeper and the Mobile Bay National Estuary Program. Even Snail Busters contributed to the effort by providing thirty, deeply-discounted apple snail traps.

The control project had a three-pronged approach: trapping adults, scraping the eggs, and treating the adults with copper. Three days before the copper treatments, Snail Busters’ traps were used to assess the initial population. “The traps worked great,” Ben said. “They really did the job!” During the treatment, the minnow traps were used as “sentinel traps” to obtain an estimate of the efficacy of the copper treatment. “Sixty to seventy percent of the snails inside the traps were dead after treatment.”

Two tons of copper sulfate was applied to Langan Pond and Threemile Creek using a blower to achieve the target of 2 ppm copper sulfate (0.5 ppm elemental copper). “Four ppm killed them every time in the lab, but 2 ppm also worked well” Ben said. In deference to preventing non-target mortality, they used the lower concentration. “Not a single fish died,” Ben happily reported. “Some Asiatic Clams (Corbicula fluminea) were killed, but that’s just a bonus, because they are another invasive, exotic species.”

Volunteers, especially hardy souls associated with Mobile Baykeeper, worked diligently to scrape apple snail eggs from the shoreline. “It’s a very time-consuming job,” Ben groaned.  “We’re going to try a pressure washer next year!” He also discussed tentative plans to reduce the dense stands of emersed vegetation that provide excellent reproductive habitat for the exotic snails.

Summing it up, Ben said, “We got a lot of apple snails and made a really good dent in the population, but we going to continue trapping and compare numbers. “So far, pre-treatment rate was 222 snails and post was 32 snails.  A seven-fold decrease isn’t that bad. The bottom line is that we need adequate funding for next year.” Thanks for the update and all the hard work, Ben. The Mobile-Tensaw Delta is certainly worth the fight! Posted by Jess Van Dyke

For additional information, contact WFF Biologist Ben Ricks by phone at (251)-626-5153, or by email, ben.ricks@dcnr.alabama.gov

Video of Lagan Pond from WPMI Ch 15 Mobile:

http://www.mefeedia.com/news/24108642

Image of trap from Press-Register, Bill Starling photographer

Lake Munson: A Case Study of the Impact of Exotic Apple Snails on Aquatic Vegetation

The old saying about Lake Munson is that “it is a beautiful lake, if you don’t look down.” Lake Munson’s beauty lies in the dense cypress strand, largely in public ownership, that surrounds it. Looking down, however, reveals that nutrient pollution and sedimentation have plagued this lake for over 70 years. This 255-acre system has been then receiving water body for treated waste water from 1934 to 1988, and for most of the City of Tallahassee’s stormwater at present. Though 25% of the watershed is protected, 50% is urbanized and home to 100,000 people. Little wonder that aquatic plants have historically been highly prolific in this fertile lake. In fact, this lake was usually “topped-out” in submersed vegetation during the growing season . . . that is, until a prolific, voracious herbivore arrived.

From 1982 to 2007, I monitored the aquatic plant communities of Northwest Florida, as DEP’s Regional Biologist.  Matt Phillips (FWCC), who filled this responsibility after I retired, recently provided me the vegetation surveys for 2008 and 2009. Lake Munson is one of the sixty public water bodies we have collectively monitored for 27 years. It is also the lake where the Island Apple Snail (Pomacea insularum) put on quite a show in 2002, painting all of the cypress trees along the shoreline with pink egg clusters. I had never seen anything like it!

The resulting population of exotic, apple snails dramatically changed the plant community of Lake Munson. Historically, submersed vegetation blanketed 80% of the lake during our surveys, necessitating the use of an airboat. In the early 90’s, the dominant submersed species were Coontail (Ceratophyllum demersum) and Southern Naiad (Najas guadalupensis).  However, in 1993, the invasive, exotic, plant  Hydrilla (Hydrilla verticillata) found its way into the lake. By 1995, hydrilla reached the surface in 200 acres of Lake Munson and that density became the norm. When the exotic snails first appeared in 2002, I noted 150 acres of Hydrilla. In two years, the Hydrilla was gone – - completely gone. In fact, no submersed, vascular plants have been found in Lake Munson, since 2004.  

Emersed and floating vegetation has fared little better. A sixty-acre stand of the beautiful, native, American Lotus (Nelumbo lutea) vanished between 2003 and 2004. The invasive, exotic, Water Hyacinth (Eichhornia crassipes) has nearly disappeared. From 2002 to 2006, a total of 330 acres of hyacinths were controlled in Lake Munson. Such control is no longer necessary. Only a trace of Water Hyacinths remains in Lake Munson. A favorite food for Pomacea insularum, Wild Taro (Colocasia esculenta) declined but rebounded on the east side of the lake in 2009, while Pomacea insularum egg deposition was concentrated on the west side (Another behavioral mystery!) .

There are some lessons here: First, the Island Apple Snail can completely strip a heavily-vegetated lake of its submersed plants and most of its emersed vegetation. Secondly, some hardy species will remain, such as Soft-Stem Rush (Juncus effusus) and Smartweed (Polygonum densiflorum). These and other apple snail resistant species should be considered first in lake mitigation, though there is still much to be learned on the subject.  Research on the food preferences of Pomacea insularum is badly needed.

So what is left in Lake Munson in terms of plants? There are plenty of blue-green algae (cyanobacteria). The lake is dominated by a dense phytoplankton bloom, consisting mainly of Microcystis spp. and Anabaena spp. The only submersed “plant” is there now Lyngbya – - a black filamentous algae. Sounds inviting, doesn’t it? Leon County continues to make great progress in improving the quality of water entering the lake, but Lake Munson remains “a beautiful lake, if you don’t look down” and, by destroying the vascular plants, the Island Apple Snail certainly isn’t helping any. By Jess Van Dyke

For more information on Lake Munson, contact:

 Matt Phillips, Florida Fish and Wildlife Conservation Commission, Invasive Plant Management Section, 3900 Commonwealth Blvd.  MS 705, Tallahassee, Florida 32399, (850) 245-2831, mattv.phillips@myfwc.com

“Lake Munson: Past, Present, and Future” by Johnnie Richardson, Water Quality Scientist, Leon County Public Works

http://www.leoncountyfl.gov/PUBWORKS/Engineering/Stormwater_Management/Lake Munson Update Short 6_25_09.pdf

Captain Copper

Since 1994, SePRO Corporation has been an innovative leader in aquatic plant management. After turning the tide against highly-invasive hydrilla (Hydrilla verticillata), SePRO’s flagship product, “Sonar” (fluridone), became the world’s leading brand of aquatic herbicides. David Tarver was a big part of that success. For over 30 years, I have known David and found him to be an excellent source of information on aquatic resource management. That is why, when he asked me to test four of SePRO’s chelated copper products (“K-Tea,” “Nautique,” “Komeen,” and “Captain”) on Pomacea insularum, I was flattered and excited. I promised speedy, conclusive results. How hard could it be? And so, the adventure began.

Bench tests are inexpensive, repeatable, and fairly reliable, though efficacy is always better in a container than in the environment. One simply places the test organisms in identical containers with identical volumes of water, varies the rate of the test chemical, waits 48 or 96 hours, and determines mortality. If, say, a fish rolls over, flairs its opercula, and no longer moves with eyes bulging, it is safe to say that the concentration of test chemical is lethal. Simultaneously, if fish are thriving in the “control” container with no test chemical added and in containers with lower concentrations, the lethal rate can be determined. No problem. Bring on the snails!

Of course, life is full of surprises. Unlike fish and other aquatic organisms, apple snails can present a number of unique challenges to the researcher. First, like fish, Pomacea also have an operculum, but it is not a bony flap protecting the gills; it is a well-sealed “trap door” that chemicals cannot penetrate. Secondly, Pomacea are amphibious, not aquatic. If an apple snail detects a toxic chemical, it can simply crawl out of the test solution. Thirdly, Pomacea are strong enough to push the tops off of containers and crawl away. Finally, a dead apple snail with its operculum closed looks exactly like a live one for many days. As I told David, those are the reasons (excuses?) a simple experiment took me 9 months and 14 trials!

From the first four trials in the fall, it became clear that “Captain” had an edge on the other products that couldn’t be explained by the concentrations of the active ingredient, as metallic copper: Captain (9.1%), Nautique (9.1%), Komeen (8.0%), and K-Tea (8.0%). So, as winter approached, all I had to do was focus on one product, determine the lethal rate, repeat the trial a few times, and report the results. It seemed simple, until I realized that water temperature played a key role in efficacy. At 20^o C, all test animals survived, but all died (except control animals) when an identical test was repeated at 28^o C. Obviously, the lethal effects of copper to Pomacea are directly related to metabolic rate, but in a greenhouse with only partial control of temperature, precisely repeating bench tests proved impossible.

I did come away with some tentative, experimental results that are worth reporting, however. First, as mentioned above, I suggest using “Captain” to control exotic apple snails. Perhaps, it is the “double chelation” that makes it more lethal by keeping it in solution longer, but it stands above the rest. Secondly, treat when water temperatures are warm (>27⁰ C or 80⁰ F). Of course, that will require more caution regarding non-target damage, i.e. “fish kills.” Third, because Pomacea can completely “clam up” for at least 24 hours, split treatments make sense. Fourth, coordinate physical removal with treatments, if practical. The snails should become vulnerable to hand-picking, as they move to areas shallow enough to extend their snorkels or to even leave the water.

What about the rate? The maximum label for “Captain” is 1.0 ppm (A.I.) or 3 gallons/ac-ft. (see below), but Pomacea insularum were vulnerable at much lower rates. In fact, higher rates may be counter-productive in that snails tended to close their opercula. At 23⁰ C, the snails produced mucus at 0.2 ppm and, at 0.4 ppm, they lay on the sides with opercula open. After 96 hours, 0.4 ppm was lethal at that cooler temperature. At 27⁰ C, 0.2 ppm was lethal after 48 hours. As mentioned earlier, bench test tend to over-estimate toxicity compared to the natural environment. Therefore, if you want to play hard-ball with exotic apple snails, treat with “Captain” at 0.3 to 0.5 ppm A.I. twice, 24 to 48 hours apart.

I am concerned about presenting these tentative results. Someone needs to fund Dr. Linda Nelson at USACOE/WES to conduct more detailed and controlled time/concentration research on chelated copper and exotic apple snails (Hint: SePRO). In any case, “Captain” appears to be your best bet, but carefully read the label. I hope to be able to try this product in the field soon and will report back on the results. My last suggestion is to read my earlier post about copper, entitled “The Copper Question.” It is dangerous to fish, if not used carefully, and is rather non-selective in terms of invertebrates. The environmentally sound way to use copper is seldom. Posted by Jess Van Dyke 

P.S. I have no relationship with SePRO, financial or otherwise. My thoughts are my own. You are responsible for the careful use of any pesticide.

Label for “Captain”: http://www.sepro.com/documents/Captain_Label.pdf

SePRO Corporation: www.sepro.com

Aloha, Poi?

When the first Polynesian settlers arrived in the Hawaiian Islands some 1500 years ago, they were smart enough to carry with them viable corms of their food staple, Taro (Colocasia esculenta) or “kalo” in Hawaiian.  Even today, every part of this plant is eaten with gusto in Hawaii. Rich in vitamins and minerals, the leaves are used to wrap meats and steamed to make “laulua.” More importantly, the corms are baked or steamed and mashed with water to produce dough-like “poi.” This sweet, starchy pudding is low in fat, high in Vitamin A and complex carbohydrates, and very easy on the stomach. In fact, “poi” is so gentle and nutritious that it is used as a milk substitute for babies with allergy problems.  Taro is more than just an excellent food source, however. According to the Hawaiian creation chant, “kalo” is the elder brother of the first Hawaiian, and thus, of the entire Hawaiian race. In Hawaii, the taro plant is a sacred, cultural icon and an important link to past traditions.

In spite of a growing demand for taro products, yields have declined in Hawaii over the past 50 years, with the lowest production (4M lbs) recorded in 2007. Urbanization took an early toll, but diseases and pests have had a major, negative influence on taro production in recent years.  Most notably, the invasive, exotic, Channeled Apple Snail (Pomacea canaliculata) has become a severe agricultural pest in the taro pondfields, called “lo’i”.  First introduced in Maui in 1983-84 for the aquarium trade and an alternative food source, P. canaliculata is now found on every major Hawaiian island, save one. The three most important taro growing communities are all heavily infested, along with the lower reaches of most streams, numerous wetlands and estuary sites (Lach and Cowie, 1998; Cowie, Hayes and Levin, 2004).

Though generating $2.7M in 2008, 105 taro farms survive tenuously in Hawaii today because of taro imports, land, water, and labor shortages, plus an array of new diseases and pests. The Channeled Apple Snail, however, may be the one pest that pushes taro farmers over the edge. Snail control methods in Hawaii include water level management, hand picking of eggs, herding ducks, employing screening on pipes and in canals, and carefully inspecting introduced plants. Nevertheless, the snails continue to take a heavy toll while adding considerable labor costs. Typical losses due to snails are 20% of the crop, but heavily infested fields can be completely wiped out, destroying 10-12 months of time and effort.

I’d like to send some of our Apple Snail Traps to Hawaii to see if they can help these determined farmers, but I lack the right contacts. All I can say is these traps are working well here in Florida. I have had the privilege of visiting Hawaii in the past, and the view of the taro fields near Hanalei was the most beautiful agricultural setting I have ever seen. One day, I hope to see those emerald fields again. “Aloha” is a word used in Hawaii to say either “hello” or “goodbye.” So, I say longingly, “Aloha, Poi” hoping that it doesn’t mean “goodbye” to such a sacred and nutritious Hawaiian food and a wonderful, traditional way of life. Posted by Jess Van Dyke

Statewide Strategic Control Plan for Apple Snails in Hawaii (9/30/2006):

http://www.hear.org/articles/pdfs/applesnailcontrolplanlevin2006.pdf

Rematch: Pomacea versus the Red Fire Ant

While collecting thousands of Island Apple Snail (Pomacea insularum) egg clusters from Wellman Pond, Dr. Sean McGlynn and I often speculated on what ferocious predator could have elicited such high reproductive capacity in this South American snail through evolutionary time. Initially, we fantasized about some large reptile, maybe a 20’ Snail Anaconda (Eunectes pomaceoraptor?), feeding so effectively on apple snails in the Argentine rivers and marshes that the remaining few adults had better reproduce prolifically for the species to merely survive. Then, as we began to notice the numerous ant bites received while wading through the shoreline plants, it came to us. Maybe, the ferocious predator wasn’t all that large. This notion was solidified when our 4-ton pile of disposed snails became one giant Fire Ant bed!

The Red Imported Fire Ant (Solenopsis invicta) and the exotic Apple Snails (Pomacea canaliculata & P. insularum) have two common traits: They are both highly invasive in the southern U.S. and their native ranges in South America generously overlap. Surely, they co-evolved in a predator-prey relationship with hydrology as a key component. Fire Ants are, indeed, ferocious predators of snails, having caused the extinction of a native tree snail in the Florida Keys (Forys et al, 2001). Stevens et al (1999) documented that Fire Ants attacked native apple snails (P. paludosa) in Florida that became “exposed during dry down conditions.” Yusa (2001) observed that “when egg masses [of P. canaliculata] were experimentally placed on levees [infested with Fire Ants], on average 50% of the eggs were lost within two days in March and 38% were lost within three days in August. No eggs were lost when ants were successfully excluded by water.” Way et al (2009) noted that “periodic drainage . . . enables [the tropical fire ant] to join the predator complex . . . valuable for ant-based control of pests such as snails” in rice paddies.

The current range of the exotic Red Fire Ant in the U.S. encompasses the projected range of the invasive South American Apple Snails. Certainly, predation by the Fire Ant will provide some friction to the rate of expansion of the exotic apple snails in the U.S., especially in areas with fluctuating water levels. Can we take further advantage of this ancient predator-prey relationship? Based on Yusa (2001), Way (2009), and personal observations, it appears a short period of water level manipulation in the presence of red fire ants can have a deleterious effect on apple snail reproduction. When the bases of shoreline plants are exposed in Wellman Pond, for example, numerous Red Fire Ants begin eagerly scouting for egg clusters. I am inclined to ask the Parks personnel not to treat the fire ant mounds there. Periodic, partial “drawdowns” also seem warranted. Let the rematch of invasive Pomacea and the Red Fire Ant continue! Posted by Jess Van Dyke

UF’s Excellent site on Red Fire Ants:

http://entnemdept.ufl.edu/creatures/urban/ants/red_imported_fire_ant.htm

National Geographic video on Fire Ants:

http://www.youtube.com/watch?v=t0fB4vYK5AE

The Black Carp: A Misguided Missile

 

flickr.com/photos/69202542@N00/88560866

The “good news” and the “bad news” regarding the Black Carp (Mylopharyngodon piceus) is that it eats snails, lots of snails. At 4-years of age, this large, Chinese fish, also called the Snail Carp, eats 3 to 4 lbs. of the mollusks per day. For 15-20 years, fish farmers in the southeastern U.S. have depended on this large Cyprinid to control the intermediate, snail hosts of trematode parasites in commercial fish ponds. For instance, only five to ten Black Carp per acre will eliminate the snails that cause the “yellow grub” fish disease produced by the common, digenetic trematode, Clinostomum marginatum. To the delight of fish farmers, there are even reports of complete eradication of snails from ponds using Black Carp.

Introducing a fish species with a high efficiency in snail predation might sound good to a commercial fish farmer, but that same eating efficiency raises alarms for those charged with protecting the often imperiled, native snails and mussels of the South. In 2007, USFWS added this 70 lb, snail-eating machine to its list of “injurious fish” and prohibits its further importation into the U.S. and interstate transport under the Lacey Act. To find out whether the Black Carp holds promise for invasive apple snail control in natural systems or is itself an exotic menace to the environment, I contacted the man who literally wrote the book on the subject (see below), Dr. Leo Nico, Research Fisheries Biologist at the Florida Integrated Science Center in Gainesville, Florida.

Dr. Nico did not mince words, stating, “I consider use of Black Carp in the wild for snail control to be very misguided.  There is much potential for harm to non-targeted native mussels and snails.  Although triploid Black Carp are considered non-viable, these fish have a life span of 12 to 18 years, maybe more. So, even the sterile fish have the potential to cause harm over a relatively long period of time. Black carp also grow to a large size — commonly over 1 meter. Individuals over 2 meters long have been taken in rivers in China and Japan.”  Now, that is a large fish!

Dr. Nico had other concerns, “Will there be problems with the certification of triplody? Will ponds containing the reproductive, diploid Black Carp be flooded allowing escape, as has occurred in the past? The food selectivity of the Black carp is largely unknown. Will they prefer native snails over the exotic apple snails? Will they consume other invertebrates, such as crawfish? They are very similar in appearance to the herbivorous Grass Carp (Ctenopharyngodon idella). Will Black Carp be misidentified as Grass Carp and unintentionally introduced into the wild?” Until those and other questions are answered, it is clear that the use of the Black Carp to control exotic apple snails in the wild is a bad idea – - a misguided missile. Posted by Jess Van Dyke    

For more information, contact:

Leo G. Nico, Ph.D.
Research Fishery Biologist/Ichthyologist , U.S. Geological Survey
lnico@usgs.gov

Black Carp (USFWS): http://www.fws.gov/blackcarp-b.pdf

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This book is available at: http://www.afsbooks.org/x51032xm.html

Save the ‘Glades!

The distribution of Pomacea insularum in South Florida

“Here are no lofty peaks seeking the sky, no mighty glaciers or rushing streams wearing away the uplifted land. Here is land, tranquil in its quiet beauty, serving not as the source of water, but as the receiver of it. To its natural abundance, we owe the spectacular plant and animal life that distinguishes this place from all others in our country.” President Harry S. Truman dedicating Everglades National Park on December 6, 1947

Half of the original, vast, tropical wetland, called the “Everglades,” has been developed for agriculture and residences in burgeoning South Florida. Much of the remainder is subject the destructive forces so common to Florida’s water bodies – - nutrient pollution, disruption of the natural hydrology, and introduction of exotic species. That is why Congress approved a plan in 2000 to Save the Florida Everglades, the most ambitious environmental fix in U.S. history. As part of this program, President Obama signed legislation on March 11th that will provide $200M for work on the Tamiami Trail, restoration of the Kissimmee River, and reinforcement of the dike around Lake Okeechobee.

Earthmoving projects are important, but the long term survival of the native biodiversity of the Everglades will hinge on invasive species control. South Florida’s spectacular native plants and animals will stand or fall in their last, great bastion, the Everglades National Park (ENP), the largest wilderness area east of the Mississippi River. At 1,400,000 acres, the ENP is the third biggest national park in the “Lower 48” and has global distinction as an International Biosphere Reserve, a World Heritage Site, and a Wetland of international Importance.

 Because of the close proximity to bustling ports importing ornamental plants and exotic pets, the ENP also has the misfortune of being home to 120 invasive plants, such as the Punktree (Melaleuca quinquenervia), Australian Pine (Casuarina equisetifolis),Old World Climbing Fern (Lygodium microphyllum), Brazilian Pepper (Schinus terebinthifolius), and 76 invasive animals, including the Burmese python (Python molurus bivittatus), the Monitor Lizard (Varanus spp.), the Spiketop Apple Snail (Pomacea diffusa), and the Island Apple Snail (Pomacea insularum).

While the native Florida Apple Snail (Pomacea paludosa) is an integral part of the Everglades ecosystem, the Island Apple Snail is an exotic interloper causing concern among National Park Service scientists. Will the expansion of this exotic apple snail cause the extirpation of the native apple snail? What effect would that have on other species, like the endangered Everglades Snail Kite (see Previous Post, Snail Kites in Trouble). Will the exotic snails grow in such large numbers that they damage the wetlands? Will they be vectors of diseases and parasites that could infect the native animals that inhabit the ENP?

In May 2005, I spoke with Skip Snow, Wildlife Biologist (ENP), shortly after the Island Apple Snails were discovered in the Old Tamiami Trail Canal just inside the park boundary. He and his co-workers were intent on executing an effective, rapid response. Park personnel immediately began conducting frequent, GPS surveys of the range of the Island Apple Snail while removing all the egg clusters and adults they could find. Though not exactly comparable, the results: 19 adults and 488 egg clusters were removed in 2005; 34 adults and 2857 egg clusters, in 2006; 17 adults and 1024 egg clusters, in 2007; and 52 adults and 508 egg clusters, in 2008. “Our surveys suggest the non-native apple snails are present only along the northern boundary of ENP.” The overall conclusion, however, is that “the P. insularum population within ENP appears to be expanding slowly” (Report by Kline & Fratto, September 30, 2008).

Yesterday, I spoke with Jeff Kline, Fisheries Biologist (ENP), and asked him how the battle with the Island Apple Snail was going, and he said, “It’s hard to say. There appeared to be a decrease in egg production, then the S-12 gates were opened and reproduction increased greatly. This may be a result of new snails moving in through the gates, or their egg laying may be cued by the environmental conditions of rising water levels or flow.  At any rate, these results preliminary. Snails are just starting to lay eggs down here now. It going be interesting to see what happens in the next few months.” Yes, indeed. My hat is off to Skip Snow, Jeff Kline, Zach Fratto, and all the others fighting the exotic onslaught in the Florida Everglades in an effort to protect “the spectacular plant and animal life that distinguishes this place!” Posted by Jess Van Dyke

 

For more information about Island Apple Snails in the Everglades National Park contact: Jeffrey Kline <jeff_kline@nps.gov> or Skip Snow <Skip_Snow@nps.gov>

Natural Resource Management/ Island Apple Snail:

http://www.nps.gov/ever/naturescience/upload/SecureFinalIslandAppleSnailFactSheetlores%20.pdf

Everglades Cooperative Invasive Species Management Area:

http://www.evergladescisma.org/

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Collaborative Research with Students

 

 Though her eclectic interests vary from fine chocolate to “the effects of macrophyte density on the interactions between benthic predators and pelagic prey” (whew!), Professor Romi Burks is keenly focused on training young minds via collaborative research on the invasive apple snail (Pomacea insularum). For five years, her Apple Snail Ecology Lab at Southwestern University, Georgetown, Texas, has enabled students to investigate multiple aspects of basic life history of this new invader. “The diversity of questions that can be explored is endless. I work directly with the student to develop his/her own research question that includes a reasonable degree of personal ownership or investment. To get the most out of the research process, students need to work on questions that pique their own interests.”

 Dr. Romi Burks writes, “When first embarking on a research projects, students review primary literature and then draft a proposal that includes a rationale, hypotheses, and proposed methods for developing experiments. We spend substantial time developing the context of the research and determining the appropriate methods. After executing the experiments, students participate directly in data analysis and dissemination through poster and oral presentations and, hopefully contributions to a scientific paper.” In fact, three of her students presented their research findings on the Island Apple Snail this week at the Texas Academy of Sciences meeting (See Recent Publications Page).  

There are two news items that Dr. Burks would like to share: First, “my South American colleagues and I think we have found a clear, native population of Pomacea insularum in western Uruguay.  I am sending samples to Rob Cowie for genetic confirmation.  This is exciting because it gives me an accessible population with which to compare patterns with the exotic population in Texas.” Second, she visited a newly reported site of exotic apple snails in Texas, where she didn’t find any live snails but numerous shells. “Based on variable shell morphology or shape, I cannot tell if the snails present are only P. insularum or could include P. canaliculata. We found an intact individual to send for genetic identification. In addition, we saw recent egg clutches which strongly suggest P. insularum. We brought back four recently laid clutches, but I’m not sure if they are going to yield any hatchlings. I expect that when it warms up that this site will definitely show productivity.”   

Aside from news, she also had some kind words: “I really appreciate the added awareness that your site brings. As you have observed, the amount of interest and incidents regarding Pomacea has been steadily rising over the past five years.  When I first got into this [snail] business, I definitely felt alone.  Now, the science is almost happening too fast for me to keep up. I also know that we have lots of information to get out to the scientific community, but the process of publication is slow — even slower when you focus on teaching undergraduates how to do research and publish. Your site speaks to the broader need for [scientific] integration. Clear time-pressure exists to protect native biodiversity. Exotic invaders routinely move faster than scientific publication processes.”

Thanks, Romi! “Scientific blogging” is a new and fascinating format. It holds great potential because it is incredibly fast. Dissemination of information on the internet is instantaneous and “viral.” Started in December, this site has been viewed by thousands of people all over the world. The downside of all blogs is that the quality of the information is unknown. Though a slow process, publication in a scientific journal is “refereed” or “peer-reviewed” to assure accuracy. I do my best to stick to the facts or clearly hedge when I’m uncertain, but I need your help. PLEASE let me know if you have any criticisms or corrections by clicking Comments above. Help make this a peer-reviewed, scientific blog! Posted by Jess Van Dyke

For more information, contact: 

Romi L. Burks, Ph.D.
Southwestern University
1001 E. University Avenue

Georgetown, TX 78626E

Email: burksr@southwestern.edu
Website: http://people.southwestern.edu/~burksr/