LdMNPV and the Management of Gypsy Moths

Gypsy moth larvae consuming leaves

William Coville – Environmental Science

Julianne Foren – Animal Science

Catherine George – Horticultural Science

John Mazzone – Turf Grass Science and Managment

 

In the late 1860’s, a French scientist brought the gypsy moth to Massachusetts from Europe in the hopes of breeding disease-resistant genes into silkworms to improve and expand the silk industry (Liebhold, 2003). Due to his incompetence, a couple of his gypsy moth subjects made their way into the New England forest and found that they could live, breed, and thrive there. The carelessness of one scientist resulted in a gypsy moth invasion that persisted over the last hundred years and encompasses various ecosystems throughout the U.S. and Canada. Lymantria dispar dispar, known as the gypsy moth, is an invasive species that acts as a major pest of hardwood trees, particularly the dominant oak and aspen (Liebhold, 2003). As an example, a red oak that lies at the entrance of Quabbin Park in Belchertown, MA has been taken down due to it being mostly dead from gypsy moth defoliation (Miner, 2018). Iconic trees in parks around the country are not spared from the damage of gypsy moths and once enough damage sets in the trees are lost from the community. Not only does the gypsy moth cause an an aesthetic decline among these once beautiful hardwood trees, but they also play the role of the small beginning in a larger catalyst effect. They cause severe defoliation among the trees they feed on and cause harm to native species as well. One scientists economic greed and thoughtless actions have resulted in ecological destruction that has lasted and will continue to last well beyond his lifetime.

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Managing Overpopulated Feral Horses in the Great Basin, USA

Emily Bartone, Natural Resource Conservation; Charlotte Sedgwick, Animal Science; Derek Tripp, Building Construction Technology

Feral, invasive horses crowd government-managed corrals

The Great Basin of the United States is currently inhabited by over 80,000 wild non-native horses. Being a wild non-native species, they survive without the assistance of humans in a region outside of their native distribution range. The horses we now see in the Great Basin were brought to this continent by Europeans during colonization. Historically, large predators such as mountain lions and wolves also roamed the landscape and could control these populations. Humans eradicated nearly all large predators during the past century of extensive development. This has left many prey species, including horses, free to expand without limit (Jackson, S., 2018). Continue Reading

Fighting Gypsy Moths With The Fungal Predator E. maimaga

Gypsy moth on oak leaf

Authors: Izaak Jankowski (Animal Science), Reilly Mcnamara (Animal Science), and Quinn Slavin (Horticulture)

The year is 1868, and a French scientist by the name of Leopold Trouvelot has just accidentally released an organism that will ruthlessly defoliate trees of Massachusetts forests in the years to come (DEEP, 2018). This disastrous creature is none other that the Gypsy moth; a species of moth which has been living and thriving in European and Asian ecosystems for thousands of years (Libehold, 2018).  It took this moth ten years prior to establishment to reach a population level that was sizable enough to notice (Libehold, 2018). Within 100 years, this moth had spread from the point of origin in Boston to areas all throughout the northeast coast, into the great lake states, and even into further northern areas such as Quebec and Ontario (DEEP, 2018). This rapid expansion was fueled by the vast amount of plant species the moth is able to feed upon and the limited predator it had.   Continue Reading

Invasive Burmese pythons eat their way through southern Florida: the unexpected effect on our health.

Kaley Fournier (Natural Resources Conservation), Edward Hines (Environmental Science), and Nicholas Stevenson (Animal Science).

 

 

Image result for invasive burmese pythons catch

 

It starts with a headache. Perhaps you develop a fever and become physically ill. You chock it up to the flu and try to let it run its course. What you don’t know; you’ve been infected. Once symptoms start to show, death is expected within 2 to 10 days. Even if you get to a doctor in time to save your life, you will most likely be left with mental and physical disability (Center for Disease Control and Prevention, 2016). Where exactly did you come across such a dangerous virus? Your own backyard. Eastern Equine Encephalitis virus is one of the most severe mosquito-transmitted diseases in the United States with approximately 33% mortality and significant brain damage in most survivors (CDC, 2018). The cause of this EEE scare is something unpredictable. The cause can be traced back to something much larger than a mosquito, Invasive Burmese pythons. This snake has slithered its way through southern Florida, devouring native wildlife in its path. This sharp decrease in wildlife populations has forced a change in the animals in which mosquitoes find their dinner. A change to disease ridden animals. Once mosquitos feast on infected hosts, they too become infected. This leaves us with not only wildlife populations to worry about, but also our own health. Continue Reading

Say “Neigh” to Feral Horses: How to Control the Overpopulation of an Iconic Species

 

(©Gail H. Collins/USFWS)

According to Mark Wintch, a farmer in Nevada, “If I put my cows out here they will starve” (Philipps, 2014, para. 3). Farmers play a key role in producing food for all of us to eat. This difficult job of ensuring that there is sufficient land and food for their animals shouldn’t come with any more obstacle, but their job gets even harder with the increasing population of wild horses. Feral horses pose numerous threats to not only United States ecosystems, but also to those using public lands for agricultural purposes.

Although horses impact farmers, it is difficult to manage them because they are considered a charismatic or iconic species in many places including the United States (Bhattacharyya, Slocombe, & Murphy, 2011). A charismatic species is one that humans place a unique value upon in regards to cultural, historical or personal significance, or based on aesthetics.  In places like British Columbia, horses pose similar threats, yet management actions became restricted due to political and cultural values placed on horses due to historical significance (Bhattacharyya et al., 2011).

Even though a majority of American society admires feral horses, wild horses still degrade soil and destroy vegetation cattle farmers use to feed their animals. This problem of limited space and vegetation for cattle will only get worse as horse populations grow. Without proper management, the horse population may near 100,000 wild horses by 2019-2020 (Philipps, 2014, para. 7). Since feral horses share 60-80% of the diet of cows, an increase of horse population will affect a farmer’s life even more (Beever & Brussard, 2000, p. 238). Mark Wintch now needs to import his cattles’ food from elsewhere because he can’t put cattle out on pasture due to destroyed land (Philipps, 2014).  Today, 155 million acres of land gets leased out to cattle farmers, which is nearly 25% of the total 640 million acres of United States public land (Bureau of Land Management [BLM], n.d;Vincent, Hanson & Argueta, 2017).  Feral horses inhabit approximately 34 million acres of grasslands and fields on public land in Montana, Idaho, Nevada, Wyoming, Oregon, Utah, California, Arizona, North Dakota and New Mexico as well the Shackleford, Sable, Assateague, and Cumberland Islands (Bradford, 2014). Farmers can lease public land and increase their contributions to the economy when horses reach a manageable population size.

Feral horses in the United States are causing approximately five million dollars in damage to the United States ecosystems’ vegetation (Pimentel, Lach, Zuniga, & Morrison, 2000, p. 54). Since these animals do not belong to any organization, people or group, they are not contributing to the economy and only inflicting ecological damage. In contrast, farmers who use federal land to graze are required to pay the Forest Service or the Bureau of Land Management for leases and permits to graze.  Feral horses pose an economic threat as they are causing only damage to vegetation found on public lands and contributing nothing.

Horses follow no invisible boundary where one farmer’s land ends and another begins, which is one of the reasons why feral horses negatively impact cattle farmers in the United States. Cattle farmers are forced to sue the government just so that the feral horses get removed from the land that they lease. Farmers are even encouraged to “voluntarily” reduce their herds to half of their original size just so that they can keep up with the damage done by feral horses on grazing land  (Philipps, 2014).

There has been a long history of horses in our country. While interwoven with United States culture, their ecological clash negatively affected the United States’ ecosystem.  Horses were introduced to North America by Spanish explorers in Mexico during the early 1500s and slowly roamed northwards into the American heartland (Kirkpatrick & Fazio, 2010). Horses overpopulated these areas because of the lack of natural predators coupled with an abundant amount of grassland (Bradford, 2014). Currently, the government wonders what’s the best way to combat this overpopulation. Managing these horses needs to become a bigger focal point for federal regulators. For proper management of wild horses, the United States government must classify wild horses as an invasive species. The definition of an invasive species is an organism that causes ecological harm where it isn’t native (National Oceanic and Atmospheric Administration [NOAA], 2017, para. 1). Horses fit this definition as they affect the U.S ecosystem while they originally came from overseas. The federal government does not define horses as an invasive species, but is currently under growing pressure to add horses to the invasive species list. Due to the dwindling wild horse population in the 1970s, wild horses were initially protected by the Horse and Burro Act of 1971, but with added protection the wild horse population exponentially grew and caused dramatic impacts to the United States ecosystem (Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program, 2013, p. 15). These horses are feral and a nuisance to ranchers because of their effects on prairie grasslands, which in turn limits the amount of food for cattle.

(The National Wild Horse and Burro Center at Palomino Valley)

Before the Horse and Burro Act of 1971, there was growing widespread public concern about the wellbeing of horses (Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program, 2013, p. 15). Unlike the current state of feral horses where they are viewed as a nuisance, wild horses used to have a declining population. Horses died due to livestock competition and roundups, where the horses were sold for slaughter (p. 15). The public looked for a way to provide a more stable environment for these creatures. The Wild Horse and Burro Act was established in 1971, giving horses allocated federal lands to roam and graze (National Wild Horse and Burro Program, 1971). The act entails the difficult process of controlling the horse population. Horses have no natural predators and under such circumstance reproduce rapidly (Bradford, 2014). The legislation makes it illegal to harm or kill horses on Federal land (National Wild Horse and Burro Program, 1971, Sec. 8). While the act seemed great at first, it became clear that there was far too many horses for the allotted land. Updated legislation includes the Stewart Provision, a law enacted in Utah that relocates horses to greener pastures to save the ecological integrity of the rangeland (St. George News, 2016). This is a good idea to start, but there are way too many horses for relocation. The number of horses needs to decrease by 32,768 to meet the target for manageable rangelands (Bureau of Land Management [BLM], 2017a, table 1). The government has recognized the issue of feral horses with legislative measures, but more action needs to be taken to effectively reduce their numbers and stop their negative impact on the United States Ecosystem.

United States ecosystems have suffered immensely due to the presence of feral horses over the years. Soil quality is an important and influential factor for successful agriculture.  The overpopulation of feral horses degrades soil quality in different ways. Due to trampling the soil around watering holes or common grazing sites, horses impacted the soil (Davies, Collins, & Boyd, 2014). In an experiment done by Davies, Collins and Boyd (2014), areas used for research were defined by exposure to feral horses; horse exposed or horse excluded. In areas where horses were excluded and not grazing, the soil stability was 1.5 times greater than horse exposed areas (p. 127). In horse excluded areas components of the soil, or soil aggregates, became more resistant to naturally occurring causes of erosion such as rain or wind. In horse exposed areas, the amount of force required to penetrate the soil was 2.5 times greater than in areas not exposed to horses, showing that high concentrations of feral horses compact the soil to a significant level (Davies et al., 2014, p. 127).  Due to the presence of horses, horse included areas are at a higher risk of erosion due to degraded soil quality (Davies et al., 2014). Erosion directly impacts agriculture as it removes the top-soil, the most productive and important part of the “soil profile” for agriculture (Queensland Government, 2016).

Feral horses degrade soil quality and thus inhibit agricultural productivity. With increasing soil compaction due to high densities of feral horses, vegetation is unable to penetrate the soil and grow. This leads to greater areas of bare soil exposure (Zalba & Loydi, 2014).  There is a high correlation between proximity to a horse dung pile and the amount of bare ground exposure likely due to the horses trampling areas where dung piles are found causing vegetation to not grow (Zalba & Loydi, 2014). Additionally, in areas that feral horses had access to, the amount of bare ground exposure was 7 times greater than in horse excluded areas in regards to riparian vegetation (Boyd, Davies & Collins, 2017, p. 413). This signifies that with a high density of feral horses present in an area, less vegetation can grow and thus more exposed soil is seen. Agriculture is affected by the presence of horses because vegetation cannot grow in such compacted and eroded soil.

Along with a markedly lower amount of vegetation, presence of feral horses negatively affects the species diversity of vegetation. Low soil quality and increased bare ground exposure decreases the ability of vegetation to grow which negatively impacts species diversity among vegetation. Plant species diversity was 1.2 times greater in horse excluded areas as opposed to horse included areas (Davies et al., 2014). With less vegetation present to hold the soil together and absorb moisture, the soil becomes more susceptible to water inundation and thus erosion.  Horses have the ability to degrade habitat quality over time by altering the seed stock and lower the carrying capacity of the soil for vegetation (Turner, 2015). The ability of vegetation to grow and the type of vegetation is important for ranchers as cattle require grasslands to graze (Philipps, 2014). The overpopulation of feral horses can significantly impact vegetation growth due to overgrazing and compacting the soil thus taking away resources needed for cattle farming.  

The overpopulation of feral horses negatively impacts United States ecosystems along with cattle farmers. As of March of 2017, there is a population of 59,483 wild horses in the United States which is an 8% increase from 2016. The wild horse population constantly trends upward due poor management techniques (BLM, 2017a). This population size is gravely too high and needs to decline to a manageable population of 26,715 (BLM,  2017a).  If horses get managed properly, then the impact wild horses have on the United States ecosystem will decrease (para. 1).

Horse management practices such as adoption and fertility management were used in the past, but proved unsuccessful in reducing horse populations. In the early 2000s, horses were captured and brought to Bureau of Land Management holding facilities which succeeded in making a 2:1 ratio of horses in the wild to animals removed for adoption (Committee of Bureau of Land Management, 2013, p. 16). From the total population of horses in these facilities, only around 4%, or 2,912 horses, were adopted out (BLM, 2017b; BLM, 2017a). The number of horses adopted is low because most of these horses are labeled as “unadoptable” and strict guidelines prohibit people from adoption. Unadopted horses can’t be sold out for adoption because of uncontrollable or tamable behaviors and age (Columbia Broadcasting System/Associated Press [CBS/AP], 2008, para. 8). In 2008 when there were 32,000 horses in captivity, between 500 and 2,500 horses got labeled as unadoptable (CBS/AP, 2008, para. 6-9). This means that there is approximately 2-8% of the horse population that are unadoptable.  Unadoptable horses or horses waiting to get adopted get brought to long term holding facilities where they are provided proper care, but uses a tremendous amount of government funding (Committee of the Bureau of Land Management, 2013, p. 212).

Although there was success with capturing, there was little success with getting the horses adopted out. In 2012, there were still 45,000 horses in holding facilities which used 60% of the Wild Horse and Burro budget (Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program, 2013, p. 16). This totals close to $40 million dollar per year to maintain these horses (Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program, 2013, p. 301). This would mean allotting around $900 per horse already in captivity per year. If more holding facilities got built to store the approximately 33,000 horses needed to be removed for manageable amount in the wild, it would cost the U.S. nearly $30 million extra. This process would cost nearly $70 million per year.

Not only are adoptions bad for the economy and inefficient, capturing and transporting increases horses stress levels (Independent Technical Research Group, 2015). Stress and proper handling was measured on live horses in Australia using different management techniques. The levels were measured based on human interaction with the horses and the time it took for the management technique to take place per horse. According to studies performed on wild horse populations in Kosciuszko National Park, management practices such as trapping and transport are used to bring wild horses to holding facilities (Independent Technical Research Group, 2015, Figure 1). The study discovered that both capture and transport affected the horses’ behavior, social structure, health, and stress (Independent Technical Research Group, 2015, p. 19-22; p. 33-39). Trapping horses normally takes several hours to perform. Transport to holding facilities can take hours to days with limited food and water for the horses. Also, these horses were never handled by humans which increases the fear and stress of the animals. The stress of capturing and transporting horses to holding facilities and the economic impact of these facilities are reasons why these practices don’t manage horses properly. With a more efficient management strategy, the horse population will decrease which, in turn, will free up land and resources for cattle farmers and ranchers.

Similar to capturing horses for adoption, fertility control is another method used in the past yet unsuccessful in decreasing the population to a manageable size.  The two main contraceptives used are Porcine Zona Pellucida (PZP) and Gonadotropin releasing hormones (GnRH). Both drugs control the estrous cycle in horses manipulating a female horse’s (mare) ability to get pregnant (Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program, 2013). Contraceptives proved unpredictable with repeated use and the difficulty of hand injections (Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program, 2013, Table S-1). Fertility control also takes a while to decrease populations. When using PZP as a fertility control method, it took 6 years of annual injections for the horse population to stabilize and not increase (Fort Collins Science Center, 2017, para. 6). It then took around another 12 years to reduce the population size down from 150 horses to 115 horses (National Park Services, 2013, Figure 1). This horse population decreased by only 37% over the course of 12 years. With the current population of horses in the United States, it would take around 24 years to reduce the current population size to a manageable number. Also, PZP increases the average age of mortality for mares ( National Park Services, 2013, p. 123-124). Mares not treated with PZP contraception only lived to an average of 6.47 years while mares given PZP lived on average 19.94 years.  The decrease in mortality increases the age limits of the horses. Since horses live longer, the fertility control is used for a longer period of times, and the horses still affect the environment.

When trying to reduce the horse population down by around 33,000 horses, it will take a lot of time and money. The vaccine, known as PZP, costs $24 per dose and lasts for one year (Masters, 2017). The lifespan of a typical adult horse given PZP is about 20-25 years (Blocksdorf, 2017), meaning that over a horse’s lifetime birth control would cost approximately $540. Incorporating the number of horses that need to be eradicated, this would bring the total cost of the birth control method close to $18 million over a horse’s lifetime; a staggering statistic that shows fertility control isn’t a sustainable or smart choice.

Not only is fertility contraception expensive to reduce horse population size, but it is also not the best method in terms of efficacy. In order for both PZP and GnRH, horses are captured and given the drug by hand or by using a dart (Committee to Review the Bureau of Land Management Wild Horse and Burro Management Program, 2013). Capturing horses then giving the horse the contraceptive is stressful for the horse. According to Kosciuszko National Park, PZP increases the desire for stallions to stay near mares (Independent Technical Research Group, 2015, p. 64-67). When mares are given PZP they become infertile, but appear receptive to male horses (stallions). This extendeds the workload for stallions during breeding seasons because they spend more time attempting to breed with infertile females. Stallions then put forth more energy to stay with the mares, which causes the stallions to become emaciated. Stallions increased reproductive behaviors by 55% when a mare was given PZP (Independent Technical Research Group, 2015, p. 64).The stallions focus more of their time on breeding than eating food. GnRH has a side effect that encourages mares to eat more vegetation (Ransom et al., 2014). Mares act infertile, allowing for increased energy use to eat more vegetation. With the use of contraceptives, horses will continue to negatively impact public agricultural land due to consuming of vegetation. Since there are so many side effects and issues with fertility control, other methods should be used to manage horse populations.

Wild horse populations are very hard to manage and bring down to a capacity suitable for the United States ecosystems. Methods such as adoptions and fertility attempted in the past reached little success. The best option for horse management is culling. Culling is the systematic killing of animals for management purposes. Culling is cost effective, ethical if done properly, and reduces the horse population rapidly (Galapagos Conservancy, n.d). Across the globe, culling projects have been shown to reduce the population of invasive species.

Culling is a common practice used to combat the negative impacts invasive species place on an ecosystem. For instance, culling eradicated an invasive species of goats on Isabela island in the Galapagos. The goats ate plants that hindered the natural ecosystem of the tortoises (Galapagos Conservancy, n.d). The islands infestation totaled around 100,000 goats. The culling project called the Isabela Project brought the number of goats down to 266 on Isabela island and other small surrounding islands. The project achieved this by getting funding to form a hunting team to eradicate the goat population. Helicopters served their purpose by quickly ridding areas of goat populations. By using helicopters, it took only one year to eliminate all goats from Santiago Island. After all the goats got culled, they were left to decompose (Hirsch, 2013, para. 8). The decomposing goats helped to give nutrients back to the Isabella Islands ecosystem that the goats originally destroyed. This concept of leaving the body of an animal in the environment to restore an ecosystem would work well after horse cull.

The removal of goats on Santiago island cost $8.7 million (Cruz, Carrion, Campbell, Lavoei, & Donlan, 2009, p. 1). Santiago Island had over 79,000 goats killed which meant it cost approximately $110 per goat. This amount of money can be compared to a case study on the cost of culling kangaroos in Australia. The government of Australia conducted culls with kangaroos due to their extremely high numbers (500 million) and consequent overgrazing of the land (Sosnowski, 2013). In 2013 there were 1,504 kangaroos shot at a total cost of $273,000, which averages to $182 per kangaroo (Raggatt, 2013).

The data from the two case studies can help predict the cost of culling horses.  This would translate to a total of $5,963,776, a substantial savings over the $18 million birth control method and $70 million captivity cost. The urgency to cull the horse population is due to the rate at which it is increasing by: doubling in size every 4-5 years (National Horse & Burro Rangeland Management Coalition, 2016). A cull seems harsh, but it’s a feasible option that is the quickest way to revert our rangelands back to their original state.

 

Helicopters used to control the wild goat population on the Isabela islands was the quickest and least stressful way of controlling invasive populations as it allowed for the most rapid means of rounding up and killing the goats (Galapagos Conservancy, n.d). This practice works well with culling large population of horses on rangelands. According to data collected from studies performed at Kosciuszko National Park, aerial shooting was the most humane method of reducing and managing an overpopulation of wild horses (Independent Technical Reference Group, 2015, Table 1). When using aerial shooting, there is no need to capture the horses (Independent Technical Research Group, 2015, p. 11) which decreases the amount of stress on the animals. Aerial shooting involves trained shooters to target horses in smaller groups and deliver instantaneous killing head shots (Independent Technical Research Group, 2015, p. 52-59). The head shots quickly kills the horse and leads to less suffering over time for each individual horse.  Aerial shooting takes an average of 73 seconds to chase and kill the horses (Independent Technical Research Group, 2015, p. 3). Aerial shooting is a quick method of reducing the population size of wild horses in a way that leads to less stress over long periods of time.

Although horses are a beloved and charismatic species to the United States, the wild horses have overpopulated and in turn negatively impact the United States ecosystems.  These animals degrade the soil and the ability of vegetation to growth. These issues negatively affect the lives of cattle farmers that reside in the Western United States. To combat the overpopulation of wild horses, culling initiatives should rapidly, efficiently and ethically decrease the population of horses. A culling initiative is the most effective and feasible means of combating overpopulation of wild horses. Lethal management will drastically decrease the population of wild horses in a short amount of time. Bringing the horse population down to 26,715 by the end of the year will allow the ecosystems to rebound to a more natural state (BLM, 2017a). Cattle farmers and agriculture will recover as the ecosystems bounce back from all of the years of exploitation by the overpopulation of feral horses.

AUTHORS

Lydia Graham – Natural Resources Conservation

Samuel Katten – Pre-Veterinary/Animal Science

Samuel Petithory – Environmental Science

 

REFERENCES

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Creating A solution For Asian Carp

 For hundreds of years, the fishing industry has not only supported millions of Americans livelihood, but has also become an immense avenue of trade and commerce across domestic and foreign borders. Invasive species threaten this avenue and are estimated to cause the United States tens of billions in environmental and economic damage each year they remain in U.S. waters (Pasko & Goldberg, 2014). An invasive species is defined as a non-native species in an ecosystem whose introduction will likely cause environmental harm (National Invasive Species Information Center, 2006). Aquaculturists introduced the invasive Asian carp to the United States in 1970 for the sole purpose of controlling algae blooms in aquaculture ponds. Algae blooms are an increase in algae and green plants, that may carry toxins, due to an excess amount of nutrients in the water that deplete the amount of oxygen resulting in the death of fish (Environmental Protection Agency [EPA], 2017). Since Asian carp feed on algae, aquaculturists believed they were the perfect solution to controlling their algae bloom issue. This worked until 1980, when flooding led to Asian carp (i.e. bighead carp, silver carp, grass carp, and black carp) escaping their aquaculture ponds and spreading into local water bodies, introducing them into the Mississippi River, Ohio River, and some of it tributaries. Once the Asian carp population settled into the surrounding bodies of water, they started to outcompete native fish by appropriating their resources. To resolve the detrimental Asian carp issue, it is essential for humans to fulfill the role of their natural predators by creating a profitable fishing market to reduce their population in U.S. ecosystems.

Asian Carp are an extremely dangerous fish for the ecosystem. The presence of Asian Carp in the Ohio River led to a population crash of Gizzard Shad, a dominant planktivore species (aquatic organisms that feed on plankton such as zooplankton) in the early 1990s (Pyron et al., 2017). Gizzard shad are small fish in the herring family that feed on these planktivore species. The Asian carp consume up to 40% of their body weight in planktivores each day, leading to a decreased amount of  food supply for Gizzard shad, which led to a decrease in their populations (Pyron et al., 2017). A clear over population of carp is present and something must be done. In 1997, fishermen reported catching over 50,000kg of carp compared to the previous catch size of 5,000kg (Chick and Pegg, 2001). Although Asian Carp are only one of 139 species in Lake Erie, they are quickly taking over space and resources, resulting in the native species becoming extinct in those specific areas (Simon et al., 2016). If time continues without a decline in population of Asian carp, it is clear that the native species will continue to decrease. If native fish continue to decrease in the Mississippi River, it will hurt the fisheries and the ecosystem because carp are effectively killing off native species due to competition for resources. The amount of taxpayers money it would take to rebuild the ecosystem is unthinkable. The jobs and money lost will be in the millions. At the end of the day, Asian carp are taking over many of the major U.S. rivers, which can be more devastating than one can imagine.  

In the river economies, commercial fisheries are essential to efforts of reducing the population of Asian carp. U.S. fisheries provide $208 billion in sales, contribute $97 billion to the nations GDP (Gross Domestic Product) and provide 1.6 million people with jobs (NOAA, 2017). To operate a healthy fishery, there must be a balance between predator and prey (Minnesota Sea Grant, 2017).  In  the U. S., Asian carp have very few natural predators, allowing them to out-compete native fish species, resulting in a reduction of those native fish populations (Minnesota Sea Grant, 2017). The decline of native fish populations negatively affects fisheries because it becomes harder and more expensive to raise and sell those fish, resulting in the closing of fisheries (Louisiana Wildlife & Fisheries, 2015). To prevent commercial fisheries from shutting down, the demand of Asian carp needs to increase. Only when demand is increased, will the process of lowering carp populations rise.

The best way to control an invasive species is to create a mechanism to prevent further introduction, create systems to monitor and detect new infestations, and to move rapidly to eradicate invaders (National Wildlife Federation, 2017). Once an invasive species establishes itself, it becomes extremely difficult and expensive to control. Lionfish are native to the Indo-Pacific, and are found invading the east coast of the US, the Caribbean, and the Gulf of Mexico (NOAA, 2017). Like Asian carp, Lionfish have very few predators due to the fact that they are non-native to the U.S. However, the U.S. combated the invasive lionfish by distributing permits for their removal to recreational divers (Florida Fish and Wildlife Conservation Commission, 2017). Permits to catch lionfish allow one to use spear fishing methods; no permit is required for the removal of lionfish with the use of hook and line (Florida Fish and Wildlife Conservation Commission, 2017). After the Lionfish are caught, they are used as a food source for people (Lionfish Hunting, 2017). Eating lionfish is good for the environment because removing them helps reefs and native fish populations recover from environmental pressures, lionfish predation, and overfishing (Lionfish Hunting, 2017). Lionfish and Asian carp are both invasive species in the U.S., and they both became successful by their ability to reproduce rapidly, outcompete native species for food and habitat, and avoid predation (NOAA, 2017). Therefore, we can confidently say that using a solution similar to what was used with Lionfish, will give us the results we are looking for with Asian carp. Asian carp have negative effects on the ecosystems they invade, but by using Lionfish as a base model, we will be able to combat the overpopulation of Asian carp by increased fishing.

Many communities rely on fishing as a source of income and food. Asian carp lack natural predators as a consequence of their rapid reproduction, which results in an absence of natural predation to bring down their population. Fortunately, Asian carp mature rapidly and reach a harvestable size at a young age (Michigan Department of Natural Resources [MDNR], 2017). Commercial fishers and markets can benefit from this rapid population increase of Asian carp because it provides an opportunity to create a market. Since commercial fishers rely on large numbers of fish, the higher the population of Asian carp, the more they are able to catch and sell them. In the U.S., humans are the main predators of Asian carp, resulting in the removal of more than 750,000 kg of bighead carp from the Illinois River over a four year period (Ridgway & Bettoli, 2017, p. 438). Asian carp can create plentiful commercial fishing jobs and increase demand with the establishment of a proper marketing strategy.

To eliminate the over population of Asian carp, we need to create a market that increases the demand of Asian carp. Once the demand of Asian carp increases, hunting pressure will also increase. Private industries are actively developing products and markets that utilize Asian carp in a high volume to keep up with increased fishing (Pasko & Goldberg, 2014). One of the main ways Asian Carp are used after they are caught is in food dishes (Illinois Department of Natural Resources [IDNR], 2017). In addition, Carp are commonly turned into kosher hot dogs, fish jerky and omega-3 oil supplements (Modern Farmer, 2015). The community of Chicago was given an opportunity to sample the healthy and tasty fish free of charge, while teaching them about efforts to protect the Great Lakes from the invasive Asian carp (IDNR, 2017). We aim to eliminate the negative perception of Asian carp through public exposure and outreach to promote it as a quality food item in domestic and international markets.

Asian carp have the potential to invade the Great Lakes if no action is taken towards decreasing their population. Bighead and Silver carp eat 5-40 percent of their body weight each day (Asian Carp Response in the Midwest, 2017). They are filter-feeders, meaning they consume plankton, algae, and other microscopic organisms. Native fish populations rely on the same plankton as their main source of food during their larval stage. If Bighead and Silver carp populations increase they can wipe out the larval population of native fish by striping away their key sources of nourishment at the vulnerable larval stage (New York Invasive Species Information [NYISI], 2011). If Asian carp spread to the Great Lakes, they will negatively affect the $7 billion/year fishing industry by out-competing native fish species for food and habitat.

If Grass carp were to spread into the Great Lakes, they will cause degradation of the water quality and damage to wetland vegetation by consuming aquatic plants (NYISI, 2011). Their foraging disturbs lakes and river bottoms, destroys wetlands, and increases murkiness in the water, making it more difficult for native fish to find food. The destruction and loss of aquatic vegetation also leaves native juvenile fish without proper cover from predators and reduces spawning habitats (Fisheries and Oceans Canada [FOC], 2017).

Once Black carp reach the Great Lakes, they will cause a decline in the native mussel population (Michigan Invasive Species [MIS], 2017). Black carp consume native mussels and snails posing an immediate threat to the Great Lakes ecosystem (MIS, 2017). Many of the native mussels are already considered an endangered species and the introduction of Black carp would only make it worse (MIS, 2017). A severe decline in the mussel population would be a huge problem for the Great Lakes. The decline of mussels will negatively affect the water quality because mussels act as biological filters that keep the water clean and healthy (State Of The Great Lakes, 2005). Mussels are also eaten by other animals, such as fish, otters, and birds. The decline of mussels in the Great Lakes mean less food for its predators, potentially resulting in a decline in those animals as well (State Of The Great Lakes, 2005). Although mussels may seem to be a insignificant animals, they are extremely important to the Great Lake’s ecosystem in many ways (State Of The Great Lakes, 2005). The decline in mussel population would result in a decline in water quality (mussels are filter feeders), as well as a decline in other native species’ populations who already depend on them for food (State Of The Great Lakes, 2005).

While the market for Asian carp is strong internationally, there has been some resistance in the U.S. due to the fact that Asian carp are looked at negatively as bottom feeders by society (Varble and Secchi, 2013). One way that markets have started to overcome this resistance is by simply referring to Asian carp as “silverfin”. The University of Arkansas conducted a blind taste test between canned tuna, salmon, and carp, this resulted in canned carp being rated better than both tuna and salmon (Varble and Secchi, 2013). This supports the theory that most of the resistants in the U.S. is due to the fact that society views Asian carp negatively (Varble and Secchi, 2013). If Asian carp markets start referring to them as “silverfin” there could be less resistance to the consumption of Asian carp because it would look  more appealing to the public (Varble and Secchi, 2013). Other countries have utilized the fact that Asian carp reproduce with large amounts of eggs as another avenue of profit (Varble and Secchi, 2013). The collection of carp eggs has become a growing part of the caviar market but has yet to be utilized in the U.S. (Varble and Secchi, 2013).

The market price of Asian carp is very low because of its current abundance in U.S. waterways (Varble and Secchi, 2013). People believe that the quality of meat Asian carp provides is low because the price to purchase it is also low (Varble & Secchi, 2013). If communities are made aware of the quality and palatability of Asian carp, the demand for them would increase in local markets (Varble & Secchi, 2013). Many communities pride themselves on local food production and consumption, which could be a valuable asset in marketing the carp. Local production of Asian carp can be paired with the negative environmental impacts they cause to help increase consumption of Asian carp in communities surrounding areas inhabited by Asian carp (Varble & Secchi, 2013).

The local and commercial fishing industries are an extremely important part of the United States environmental and economic well-being. Invasive Asian Carp are a key factor to a massive native fish decline in the Mississippi River (Asian Carp Response in the Midwest, 2017). Without fish, people would lose not only a food source, but a source of income and a way to keep rivers and lakes clean. Asian carp are a type of fish that are very good at hunting prey and can reproduce quickly, making it essential to create a population decline in order to protect the natural ecosystem. Creating a consumer market for carp will not only solve the problem of overpopulation, it will also be beneficial for our economy and our environment. As of recently, various fisheries all over the country have suffered due to these carp spreading into more and more waterways (NOAA, 2017). Since fisheries are a billion dollar industry, Asian carp are essentially creating an economic problem (NOAA, 2017). To reduce the current population, fishermen first need to fish out a majority of the carp, which they will then sell to local businesses and vendors. Once the fish is purchased by these businesses and vendors, they can sell the fish in the public market, making two branches of this economic sector profit, therefore boosting the economy. In turn, the Carp population due to increased demand will eventually become extremely low, allowing the native fish populations to become established once again. The native fish could then start to rebalance the natural food web again, keeping the rivers healthy.  If Asian carp are only minimally hunted, there is serious risk of the health of all native species in the Mississippi river as well as the river itself. Asian Carp are clearly a very successful yet detrimental, invasive species to the United States. However, their success may lead to their demise. If we can create a high demand market for carp, utilizing humans as their natural predator, we can restore the river environments that have been harmed, while creating jobs and food for people.

AUTHORS

Tiffany Vera Tudela- Natural Resource Conservation

James Sullivan- Natural Resource Conservation

Shannon Gregoire- Animal science

Dylan Osgood- Building Construction Technology

 

REFERENCES

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Chick, J. and Pegg, M. (2001). Invasive carp in the Mississippi river basin. Science 292(5525), 2250-2251. doi:10.1126/science.292.5525.2250

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Fisheries and Oceans Canada. (2017). Asian Carp. Retrieved from http://www.dfo-mpo.gc.ca/science/environmental-environnement/ais-eae/species/asian-carp-fact-sheet-eng.html

Fisheries, N. (2017, May 09). NOAA Fisheries Releases Fisheries Economics of the U.S. and Status of Stocks Reports. Retrieved December 04, 2017, from http://www.nmfs.noaa.gov/stories/2017/04/05_feus_sos_reports.html

Florida Fish and Wildlife Conservation Commission. (2017). Lionfish Recreational Regulations. Florida.

Illinois Department of Natural Resources. (2017). Target Hunger Now! Program Features Asian Carp. Chicago, Illinois.

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Lionfish Hunting. (2017). Eating Lionfish. Retrieved from https://lionfish.co/eating-lionfish/

Louisiana Wildlife & Fisheries. (2015). Asian Carp Creating Problems In Louisiana Waterways. Baton Rouge, Louisiana.

Michigan Department of Natural resources. (2017). Invasive Carp. Michigan.

Minnesota Sea Grant. (2017). Aquatic Invasive Species. Retrieved from http://www.seagrant.umn.edu/ais/

National Oceanic and Atmospheric Administration. (2017). What is a Red Tide.

National Park Service. (2017). Asian Carp Overview. Mississippi.

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New York Invasive Species Information. (2011). Asian Carp. Retrieved from http://www.nyis.info/index.php?action=invasive_detail&id=29

Pasko, S. and Goldberg, J. (2014). Review of harvest incentives to control invasive species. Management of Biological Invasions 5(3), 263-277. doi: http://dx.doi.org/10.3391/mbi.2014.5.3.10

Pyron, M., Becker, J. C., Broadway, K. J., Etchison, L., Minder, M., Decolibus, D., & Murry, B. A. (2017). Are long-term fish assemblage changes in a large US river related to the Asian Carp invasion? Test of the hostile take-over and opportunistic dispersal hypotheses. Aquatic Sciences, 79(3), 631-642. Doi:10.1007/s00027-017-0525-4

 

Ruffe: A New Threat to Our Fisheries. (n.d.). Retrieved December 04, 2017, from http://www.seagrant.umn.edu/ais/ruffe_threat

Simon, T. P., Boucher, C., Alfater, D., Mishne, D., & Zimmerman, B. (2016). An Annotated List of the Fishes of the Western Basin of Lake Erie with Emphasis on the Bass Islands and Adjacent Tributaries. The Ohio Journal of Science. 116(2), 36-47. Doi: 1874392640.

 

Varble, S., & Secchi, S. (2013). Human consumption as an invasive species management strategy. A preliminary assessment of the marketing potential of invasive Asian carp in the US. Appetite, 65, 58-67. doi:10.1016/j.appet.2013.01.022

What We Do to Stop Invasive Species. Retrieved December 04, 2017, from https://kids.nwf.org/Home/What-We-Do/Protect-Wildlife/Invasive-Species.aspx

Alligator Gar As Means To Control Asian Carp

 

        Jordan Fielder, a nineteen year old boy, was enjoying a fun day on the Illinois river with his family when all of a sudden a large fish launched from the water like a missile, and smashed into his face. The fish fractured his nose, dented his forehead, and shattered bones in his eye sockets and brow (Schankman 2015). Jordan commented, “If it had hit me any harder it could have broken my skull bones and essentially damaged my brain and killed me on the spot”(Schankman 2015). For Jordan this was a fun family day on the river, turned to a near death experience. The fish responsible for this, is the invasive Asian carp, which is overrunning the Illinois river and its surrounding waters including the Mississippi, Missouri and Ohio rivers (Hayer et al. 2014). The carp easily become scared by boat motors or other loud noises which causes them to jump out of the water (Shankman 2015), turning their large bodies into a dangerous projectile which can clearly hurt people in their path. Jordan’s experience is not uncommon as this has happened to many others. As harmful as they can prove to humans, they are just as bad for the ecosystem, as is seen with many invasive species.

        In the 1950s, East Africans introduced Nile perch to Lake Victoria to strengthen a lacking fishing industry (Micalizio, 2015, p. 1). The environmental effects of this introduction completely transformed the Lake Victoria ecosystem. Voracious appetites and bountiful prey allowed the top-tier predator Nile perch to cause the extinctions of over 200-species of fish native only to Lake Victoria, such as cichlids. Native predatory catfish species such as the Sudan catfish and African sharptooth catfish also suffered as a result of the Nile perch (Frans Witte, 1997). In 1973, the Sudan catfish and African sharptooth had catch rates of 44 pounds per hour. However, by 1985 they had catch rates of zero. Whereas the Nile perch showed a catch rate of zero in 1973, but jumped to 176 pounds per hour by 1987, 4 times higher than the native catfish species when they were at peak abundance (p. 28). A domino-effect occurred from the loss of native species, leading to outbreaks of insects and algal blooms (Nile perch , 2014, p. 6). Some of the largest impacts came down on the backs of humans. The fishermen and their families cannot eat the fish themselves, they have too high a value and eating them means a loss in profits, yet fishermen go on longer fishing trips now than in the past to try and keep up with demand (p. 9). The Nile perch serve as an example that represents how non-native freshwater fish introductions can derail an ecosystem and community if not well-controlled or managed (Vitule et al., 2009). There is such an introduction happening right under our noses here in the United States, the invasive Asian carp.

        Ecosystems have a delicate balance in which organisms work in harmony, each occupying their own little niche (the role of an organism in an ecosystem) (Biology-online.org, 2016), when a new organism enters that ecosystem, they can occupy another species’ niche, competing with them for resources and food. Unfortunately, native species often lose this competition to the new invaders. The National Invasive Species Information Center (NISIC), defines invasive species as “non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health” (“What is an invasive species?” 2012, para. 1). One such invasive species, the Asian carp, have made a name for themselves here in the United States, introduced to control phytoplankton and for aquaculture.

        Native species of carp have existed in the United States for over 100 years, and the species called the “common carp” has lived here with little environmental impact (Naylor et al., 2001).  The newer and more potent Asian carp describe 4-different species, the bighead, grass, black, and silver carp. The U.S. imported silver and bighead carp in the 1970s from Asia for research purposes, putting them into wastewater lagoons and aquaculture ponds and observing if they improved water quality (Naylor et al., 2001, para. 2). Federal and state agencies, private citizens, and researchers imported and introduced the grass carp from eastern Asia in 1963 to control aquatic plants in fish farms (Grass carp, 2013, para. 1). Juvenile black carp came to the U.S., initially in Arkansas, in the 1970s when they arrived with a shipment of grass carp (Nico and Nielson, 2014). Nobody noticed because juvenile black and grass carp have nearly identical appearances. The U.S. attempted to use the black carp as a food resource and to control yellow grubs in aquaculture ponds (para. 5). Flooding events in aquaculture ponds connected to rivers allowed the silver, bighead, grass, and black carp to escape into the Mississippi River and Missouri River where they now have established breeding populations (Naylor et al., 2001, para. 2; Grass carp, 2013, para. 1; Nico and Nielson, 2014, para. 5).

        Invasive Asian carp demonstrate trends of rapidly increasing abundance a short time after their introduction. In the Missouri River in South Dakota, the abundance of Asian carp skyrocketed from 2009-2012 (Hayer et al., 2014, p. 294). In 2009, a fishing survey in the Missouri River caught no Asian carp. By 2012, fishing surveys caught 35 fish per hour (p. 294). In 6 sections of the Mississippi River, the number of Asian carp caught went from <50 per hour in 2003, to 775 per hour in 2012 after their introduction (Phelps et al., 2017, p. 7).  This 15x increase demonstrates the ability of Asian carp to overwhelm an area in as little as 9 years.

        Asian carp often outcompete native species for food (Asian carp overview, 2015). Asian carp filter feed and voraciously consume algae and zooplankton, primary food sources for native fish species like gizzard shad, paddlefish, and bigmouth buffalo (Asian carp overview, 2015; Irons et al., 2007; Sampson et al., 2009). Small zooplankton such as rotifers compose a large part of the diet of many native filter feeders, however, Asian carp consume them as well. In one section of the Mississippi River, Asian carp cut the abundance of rotifers from 6000 per liter of water in 2002, to 3500 in 2003, nearly a 50% decrease in only one year (Sampson et al., 2009, p. 488). Thus reducing the amount of available prey, and forcing predatory species to feast more heavily on other organisms such as copepods, seldom consumed by many fish, but compose nearly 62% of the diet of endangered paddlefish (p. 489). The decrease in rotifer abundance observed by Sampson et al. (2009) therefore means that fish will have to search for and eat different prey species instead of relying on rotifers the way they did before Asian carp.

        Asian carp reduce the abundance of native species where they colonize (Hayer et al., 2014; Phelps et al., 2017). In 2009, Asian carp represented <1% of the catch in the Missouri River, whereas the native emerald shiner fish comprised roughly 30% of fish caught in 2009. In 2012, Asian carp composed 50% of the catch, and emerald shiner dropped to 5% of the catch, equating to a 6x decrease in emerald shiner, and a 50x increase in Asian carp  (Hayer et al., 2014, p.298). In the Mississippi River, Asian carp caused the bigmouth buffalo population to decrease by 10%, instead of following the historically-observed increase of 35%. After the invasion of Asian carp, the number of buffalo caught per hour decreased from 178 to 85 (Solomon et al., 2016, p.8). In another study on the Illinois River, the bigmouth buffalo’s abundance declined by 80% in 2005, compared to the abundance recorded from fishing trips in 1995 (Irons et al., 2007, p. 268). In this same stretch of river, the annual Asian carp catch increased from 0 in 1995, to 500 in 2005 (p. 265)

        Predatory and game fish populations also undergo negative changes because before the young become large enough to eat other fish and crustaceans, they eat small plankton consumed by the invasive carp (Solomon et al., 2016, p.1). This means that if the carp kill off the young of a species, they will do massive damage to the species populations as a whole. For example, two species of crappie showed dramatic decreases in abundance, Black crappie populations decreased by 61.79% and white crappie populations decreased by 45.98% (Solomon et al., 2016, p. 8). Carp do not feed on crappie, but they feed on the same thing as the juveniles, causing the population to have trouble growing. The removal of plankton by Asian carp also casts residual effects on important prey species for predatory fish. For example Asian carp negatively affect gizzard shad, another filter feeder. These shad comprise an important food source for predators of the ecosystem (Phelps et al., 2017, p. 11). Shad are a staple food source of a very popular gamefish in the Largemouth Bass, if there are less shad, then the bass will not do as well (Storck et al. 2011, pg. 1). Gizzard shad went from an average biomass increase of 10% to nothing because the Asian carp reduced their survival rate from 80% to 10%, preventing their population from growing (Phelps et al., 2017, p.5). Fish catches also decreased by almost half for the shad going from 7186 per hour to 3810 per hour (Phelps et al., 2017, p.6). This massive decrease sends a negative effect right up the food chain of an ecosystem. Directly related to the shad population going down, the CPUE of Asian carp increased over the same period of time showing that the native fish get outcompeted (Phelps et al. 2017, p. 11). As carp became more prevalent in floodplain lakes, predators such as bass, catfish, gar and bowfin started to disappear. (Phelps et al. 2017, p.9).  

        One reason that carp have become so abundant is that native fish have shown a preference for native prey when given a choice between the two. Native piscivores of the Mississippi River Basin showed negative selectivity or preference of silver carp versus native prey species (Wolf et al. 2017, p. 1142). White bass tested in this study, chose Asian carp first only 3 of 29 times (Wolf et al., 2017, p. 1141). The study showed that largemouth bass chose to eat Asian carp first instead of native prey species only 4 of 29 times (Wolf et al., 2017, p. 1141). However largemouth bass did show a positive selection of 0.23 specifically for grass carp, however they still negatively selected for Asian carp in general with a -0.08 (Wolf et al., 2017, p. 1141).  In this study a score of 1 represented the highest selectivity for consuming Asian carp and a score of-1 represented a complete avoidance of Asian carp.  The study showed that all native piscivores showed little or no preference for Asian carp except the longnose gar, which had a selection for Asian carp of 0.12 (Wolf et al., 2017, p. 1141). Asian carp’s low selectivity by U.S. piscivores, (Wolf et al., 2017) demonstrates that using predators to control Asian carp infestations in U.S. waters will only be successful through the implementation of one of the carp’s natural predators into their new environments in the U.S.

        However as none of Asian carp’s natural predators live in U.S. water systems, all of Asian carp’s natural predators would also be invasive species to these ecosystems and their implementation into U.S waterways could cause further ecological impacts that are just as bad or worse than the negative impacts ensued by Asian carp infestations (National Wildlife Federation, n.d.). A situation similar to this occurred when the cane toad was introduced to Australia in an attempt to control pests. These toads succeeded at their job but caused many negative side-effects to the environment such as consuming large quantities of non-pest animals such as small lizards. (Frontier Gap, 2015, para. 4) These toads were able to grow in numbers and cause such havoc due to their toxic skin and glands which leave them with no predators in this new environment. (para. 4) With this knowledge at hand, the introduction of non-native predators in efforts to control the effects of Asian carp infestations does not seem like a  smart option.

        Invasive species cause vast amounts of damage to humans every year. The most recent economic study shows that the United States spends more than $120 billion every year to control invasive species (Scully, 2016, para. 3). In 2010 alone, the U.S. spent $78.5 million dollars to keep Asian carp from reaching the Great Lakes (“The cost of invasive species,” 2012, para. 11). That’s enough money to buy 20-Hubble telescopes every year (Goldman, 2012, para. 2). Even if you don’t care about fish, you should find this alarming because Asian carp affect rivers that flow in and out of the great lakes.With sixty-five million pounds of fish harvested from the great lakes every year, the lakes generate about one billion dollars in revenue for the local economy (“About our lakes: economy,” n.d., pg. 1). If Asian carp decrease native fish populations by eve one percent, that is a lot of money to lose. So clearly there is high potential for a significant problem to occur.

        So it is clear that asian carp cause problems wherever they invade. People are not blind to this and have done things to try to combat their invasion. The Army Corps of Engineers implemented an electric fence along the Chicago ship canals to keep them from moving upriver (Kraft, 2013, para 6) This is bad for two reasons. First, it stops native fish from moving along the river, and second the power for the fence has shut off, and carp moved past it (Kraft, 2013, para 6). Another option is dumping poison into the rivers to kill off the carp (Hasler, 2010, para 10). This is bad because it could kill off all of the native species along with it, and dumping poison into a river will only carry it further upstream, affecting more than just the target area. Furthermore, sometimes the poison just does not work (Hasler, 2010, para 5).  With people struggling to come up with a viable solution, we have a proposition; add a predator into to U.S. waterways to combat the Asian carp.

        Luckily there is one species of predatory fish native to the Southeastern U.S., called an alligator gar, that many scientists are arguing could be used as an effective predator of Asian carp. (“How to combat Asian carp? Get an alligator gar,” 2016). The use of a native predator could prevent against any negative effects that could be incurred from the of introduction of another invasive species to U.S. waterways. Alligator gar once existed through the Mississippi River and its tributaries all the way from Ohio to Illinois and down to the Gulf of Mexico. They now however, only live in in the Mississippi River valley from Arkansas southward (U.S. Fish and Wildlife Services, n.d., para. 12). The reason for this mass decline in alligator gar populations is mainly caused by humans. For one many people saw  alligator gars as a “trash fish” with less value than commercial game-fish and targeted them for extermination and control (para. 13). Some of the other main reasons that humans targeted alligator gar in this way include that they are big, monster looking fish, thought to attack humans and they were thought to deplete populations of commercial gamefish (Cermele, 2016). Although these two notions about alligator gars fueled the drive to eradicate these species, both of them ended up being false. There has never been a confirmed attack of an alligator gar on a human to date (Cermele, 2016, para. 6; Parks, 2016, para. 1). Additionally, alligator gar do not eat many game-fish as they are opportunistic feeders, eating anything that swims in reach of them, and most game fish are relatively stationary, meaning that if alligator gar wanted to eat them, they’d have to hunt them down, something that is just not in their nature (Cermele, 2016, para. 10; Department of Natural Resources, para. 10). Scientists have only disproven these false notion recently through studies allowing light to shine onto alligator gars potential for controlling Asian carp infestations and reintroduction efforts are already underway in Illinois (Department of Natural Resources, n.d., para. 5). State officials must consider two constraints to determine if reintroduction efforts of alligator gar in U.S. waterways will be an effective measure of combatting Asian carp infestations; effects of alligator gar on Asian carp populations and feasibility of an alligator gar reintroduction program.

        Obviously before considering feasibility of an alligator gar reintroduction, policy makers should determine the effects an alligator gar reintroduction will have on Asian carp populations in U.S. waterways. Many people including Dan Stephenson, biologist and chief of fisheries at the Illinois Department of Natural Resources, criticize that alligator gar can actually consume Asian carp, saying they aren’t big enough to do so. He says that their jaws just won’t open wide enough to fit most Asian carp (Garcia, 2016, para. 6). However alligator gar one of the  largest freshwater fish in North America and the largest fish species in the Mississippi River Valley (U.S. Fish and Wildlife Service, 2015, para. 3), an ecosystem that the Asian carp have spread throughout. At maturity they can grow to be 10 feet in length and weigh up to 300 pounds (“Alligator gar,” 2009, para. 2). On the other hand, the four Asian carp species that have invaded U.S. waterways can only grow to be at maximum, about 3.3-6 feet in length and weigh 70-99 pounds in weight (“Asian carp,” 2017). Considering that the biggest alligator gar can grow to be 3 times the weight of the biggest Asian carps in U.S. waterway and are opportunistic predators (Department of Natural Resources, n.d.), it is perfectly reasonable to assume that alligator gar can consume Asian carp, if not as full grown fish but at the very least as adolescents; which could be even more effective as it would reduce the amount of Asian carp surviving to reproductive maturity.

        Alligator gar do in fact mostly target rough fish, including carp, and gizzard shad (Cermele, 2016, para. 10, Department of Natural Resources, para. 10). Although data is scarce on alligator gar selectivity towards Asian carp specifically and is not well documented, more is known about other species of gars’ selectivity for Asian carp. According to recent research from from Western Illinois University the shortnose gar has a positive selection for Asian carp as they existed in the highest abundance, above any other prey item, in shortnose gars stomachs (David et al., 2016,  para. 5). Additionally, as previously stated, Wolf et al. (2017) found that longnose gar showed a positive selection for asian carp. Since these species are very closely related to alligator gar, it is likely alligator gar would have a similar, positive selection for Asian carp as longnose and shortnose gar and consume Asian carp in similar numbers. Alligator gar would likely even consume more Asian carp biomass per fish than longnose and shortnose gar, as they are the largest of the seven known gar species (Alligator gar et al., 2009, para. 2), adding to their effectiveness.

        With alligator gars effectiveness of controlling Asian carp infestations demonstrated, the next thing to consider is the feasibility of an alligator gar reintroduction program in U.S. waterways. Reintroduction programs have been implemented successfully in the United States on many occasions bringing animals such as California condors and black-footed ferret populations back from the brink of extinction (Errick et al., 2015). In 1982, less than 22 California condors remained. However, through reintroduction efforts by the U.S. Fish and Wildlife Service started in 1985, by 2015 there were about 210 of them in the wild and 180 in captivity (Errick et al., 2015, para. 8).

         On top of returning decimated species back to stable populations, predator reintroduction programs are also a tried and proven technique for combatting the effects of rampant species population growth. The reintroduction of gray wolves to Yellowstone National Park in 1995 had immense success combatting the effects of unwanted elk population growth. All the gray wolves of Yellowstone had been hunted to extinction by the end of the 1920s (“1995 Reintroduction of wolves in Yellowstone,” 2017, para. 4). Thereby allowing elk populations to skyrocket and mass degradation of brush and trees that elk graze on (Wolf reintroduction changes ecosystem, 2011, para. 8, 1995 Reintroduction of wolves in Yellowstone, 2017, para. 5). However, in the winter of 1995/1996, scientists captured 14 gray wolves from Canada and released them into Yellowstone Park (“Wolf reintroduction to Yellowstone Park, wolf pack dynamics, & wolf identification,” 2000, para. 2). By 2015, there were about 528 total wolves in the Greater Yellowstone ecosystem (“Wolves,” n.d., para. 6). Soon after their reintroduction into Yellowstone the environment started to return to a healthy state. This increase in ecosystem health isn’t just because the wolves ate the elk and drove their populations down. In fact elk populations have actually increased since Gray wolf reintroductions into Yellowstone. For instance in 1968, only about one-third of today’s  elk numbers existed in Yellowstone (“Wolf reintroduction changes ecosystem,” 2011, para 9). Willow tree health in Yellowstone also increased (“1995 Reintroduction of wolves in Yellowstone,” 2017; “Wolf reintroduction changes ecosystem,” 2011). If 108 gray wolves living in Yellowstone can have these positive effects on the ecosystem by consuming an increasing population of elk, it is likely that a small population of alligator gar, another top predator (U.S. Fish and Wildlife Service, 2015), can have significant positive effects on U.S. waterways by consuming Asian carp. With experience gained by the U.S. Fish and Wildlife Service from past successful reintroductions of animals such as gray wolves and California condors, the department is definitely capable of succeeding at yet one more species reintroduction, this time with alligator gar, and these efforts are already underway in Illinois (Department of Natural Resources, n.d., para. 5).

         Asian carp continue to spread and cause problems for the native fish wherever they invade. In these areas, native fish populations decrease by about half through being outcompeted themselves or through their food sources dying off (Phelps et al., 2017, p.6). With Asian carp threatening to establish themselves in the great lakes, a billion dollar per year fishing industry comes under fire, as well as an amazing and unique ecosystem. Nature controls populations through a system of checks and balances. This means that if something were to keep carp populations in check, they wouldn’t be such a big problem. For example reintroducing wolves to the Yellowstone national park region to control the effects of the elk population that was getting way out of control worked out very well and allowed the degraded conditions of the willow trees that the elk feed on to increase immensely (“1995 Reintroduction of wolves in Yellowstone,” 2017, “Wolf reintroduction changes ecosystem,” 2011). In a similar way alligator gars are the answer to keeping the effects of the Asian carp in check. They grow large enough to eat them and other gars have shown a taste for asian carp. They also were native to the region before, so reintroducing them is not some radical, new idea. If you have a large prey item, introduce a larger predator to keep it in check, and that is exactly what we propose to do with the alligator gar in regards to the Asian carp epidemic that threatens the Mississippi River Valley Basin and great lakes.

AUTHORS

Samuel Romania – Environmental Science Major

Jonathan Hastings – NRC:Fisheries

Skyler Rehbein – NRC Fisheries

 

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Save the Shearwater: Feral cats pose a threat to island bird species

 

 

Masses of Yelkouan Shearwaters swarm the islands of the Mediterranean Sea in search of old lovers and new lovers during the start of the new breeding season in November. Known as wind chasers, these gray and white birds silently coast the surface of the sea until they hit land and finally begin their cackling breeding calls. Veterans of the breeding ritual pursue their mate of previous years while new birds start the quest for a lifelong partner. Once they find each other, Shearwater couples reacquaint themselves and continue the works of Mother Nature, laying one golden egg per mating pair. For the next couple of weeks both parents take turns incubating the egg and flying out to sea in search for food (Raine, n.d.). Once the babies hatch, this becomes an almost impossible task, leaving the Shearwaters exhausted from the care of their offspring. With fatigue weighing down their wings and their spirits, Shearwaters easily fall victim to ecological problems like the introduction of predators. Unfortunately, due to these problems, Yelkouan Shearwater populations are in steady decline and are now listed as vulnerable to extinction by the International Union for Conservation of Nature (BirdLife International, 2016).

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The environmental and health impacts of allowing cats outdoors

Ashley Hoffman- Natural Resource Conservation

Blake Lucas- Animal Science

Heather Moulding- Animal Science

 

4-28-15

 

Richard Conniff walked out his door one day only to notice an array of desiccated corpses, belonging to birds and small mammals, scattered about his walkway. Could all of these be “offerings” from his beloved cat, Lucky?  Unknowingly, Conniff was allowing his outdoor cat to be the perpetrator of up to 33 birds and dozens of mammal deaths yearly.  His desire to let a predator such as Lucky live a free-spirited lifestyle, had consequences beyond his realization. (Conniff, 2014)

Almost as if Karma had planned it, Lucky fell victim to the same fate that she had forced upon many others before.  One night, she and another neighborhood cat were attacked and killed by a wild animal. Conniff found the bloody remains of his companion the next morning and was devastated. Coincidently, a bobcat had jetted out in front of his car when leaving his neighborhood that same morning.  Surely, he thought, this must be the ruthless killer of the crimes the night before. (Conniff, 2014) Continue Reading