Craig Dawson, AIS Program Director DATE: June 12, 2014, Board Workshop SUBJECT: AIS Economic Study

M E M O R A N D U M

TO: MCWD Board of Managers FROM: Craig Dawson, AIS Program Director DATE: June 12, 2014, Board Workshop SUBJECT: AIS Economic Study

Background: The Board of Managers authorized the District to engage with the University of Minnesota’s Applied Economics Department to do an economic study “to estimate the economic costs and benefits of management practices designed to limit the spread of aquatic invasive species (AIS).” The purpose of such a study was to provide more informed decision-making on alternative courses of action in preventing or controlling the presence of AIS. The work performed by the University team has two parts. The first is a review of academic literature on the subject, which was presented to the Board at its January 9, 2014, workshop. Based on that review and direction from the workshop discussion, the second part investigates expenditures with associated with preventing and managing AIS. This investigation focuses on Great Lakes states as well as the State of Florida, as the latter has the most experience and expenditures for preventing and controlling AIS. As the University team has found out, in the existing literature and available information it is difficult to find the types of data or experiences to analyze the management questions the District had hoped to more easily guide decision-making.

Draft Report for Discussion: A draft of the full report, “Economic Aspects of Aquatic Invasive Species”, is included in the agenda packet. As mentioned above, the Board has already reviewed the first part of the report. The second part of the report, “Expenditures on Treatment and Control”, begins on page 38. Conclusions and final recommendations for the District begin on page 65.

In Part 2 of the report, the “analysis of AIS expenditures reflects data from public and private organizations. It does not address the added costs to private individuals nor public infrastructure, such as: increased costs in maintenance and repair for boats, docks, and lift equipment; increased maintenance and replacement costs for pipes to use lakewater (e.g., for watering lawns, etc.); the value of people’s time to perform maintenance, transport equipment for repairs, etc.; and finally, costs for public infrastructure, for example increased need to clean/maintain pipe outlets, increased need to maintain public launches and public beaches (and attendant disposal costs).” That said, the public cost for AIS treatment, not prevention, ranged from $289 to $376 per acre per year, and the cost per boat inspection was $29.

Dr. Steve Taff will make a brief presentation on the report and respond to questions from the Board. The draft report included in the agenda packet is still subject to minor revisions based on corrections noted by the University team and from the discussion with the Board at the June 12 workshop. There should be some discussion about undertaking a Phase 2 of this study, based on what further research may be warranted. The 2014 budget and workplan include $50,000 to perform such additional work.

Economic Aspects of Aquatic Invasive Species

A report to the Minnehaha Creek Watershed District

Baishali Bakshi, Frances Homans, Steven J. Taff1

June 3, 2014

1 Graduate Research Assistant, Natural Resources Science and Management Program; Professor, Department of Applied Economics; and Associate Professor, Department of Applied Economics, University of Minnesota, respectively.

Contents Overall Introduction ...... 4

Part 1: Literature Review ...... 6

Introduction to Part 1 ...... 6

Study Organization...... 7

Economic Impact of Invasive Carp ...... 10

Ecological Characteristics ...... 10

Economic Costs ...... 11

Control Strategies ...... 12

Economic Impact of Invasive Crustaceans ...... 14

Ecological Characteristics ...... 15

Economic Costs: ...... 16

Control Strategies ...... 16

Economic Impact of Other Invasive Fish...... 17

Sea Lamprey: ...... 18

Ecological Characteristics ...... 19

Economic Costs ...... 19

Control Strategies ...... 20

Economic Impact of Invasive Mussels ...... 20

Ecological characteristics ...... 21

Economic Costs ...... 22

Control strategies ...... 23

Economic Impact of Milfoil ...... 24

Economic Costs ...... 24

Control Strategies ...... 25

Economic Impact of Other Invasive Weeds...... 25

Ecological characteristics ...... 26

Economic costs...... 26

Control Strategies ...... 27

Conclusions ...... 29

References for Part I...... 31

Part 2: Expenditures on Treatment and Control ...... 38

Introduction to Part 2 ...... 38

Indiana ...... 39

Minnesota ...... 41

New York ...... 52

Wisconsin ...... 57

Florida ...... 60

Comparison of all states ...... 64

Conclusions amd Final Recommendations ...... 65

Contact Information ...... 68

References for Part 2 ...... 69

Overall Introduction This is a collaborative project between the Minnehaha Creek Watershed District (MCWD) and the University of Minnesota to conduct an initial assessment of the economic impact of aquatic invasive species (AIS) and reported AIS control strategies relevant to the Upper Midwest (Great Lakes) region of the United States. This project has two main parts: (1) a literature review of existing research on the economic impact of AIS, focusing on the Great Lakes region (Part 1); and (2) an assessment of the costs of AIS management (control) and intervention (prevention) measures for the Great Lakes states (Part 2).

To properly assess the economic costs/values of AIS control, we would ideally like to estimate both the probabilities of success/failure and the economic costs/values of any resulting infestation. As the chart below suggests, the cost of no action can be significant, but so can the cost of action without success.

In the present report, the authors had resources to address only one element of the decision structure shown here, that circled in red: the expenditures on AIS control observed in Minnesota and elsewhere. We summarize expenditures on AIS and include links to the corresponding datasets collected, their sources and contact information. We find that more research on the specific economic impacts of AIS accounting for invasion risk, management cost and potential

returns to different management actions is needed for the Upper Midwest region to determine economically efficient policy options.

Part 1: Literature Review

Introduction to Part 1 In this first part of the project, we summarize existing research on the economic impact of AIS focusing on the Upper Midwest region examining one hundred and twenty five articles classified into six major species categories: Carp (Common Carp and Asian Carp), Crustaceans (Crayfish, Spiny Waterflea, the Ponto Caspian Bloody red shrimp and the Green Crab), Milfoil (Eurasian watermilfoil), Mussels (zebra, quagga and golden mussel and Asian clam), Other Fish (Sea Lamprey, Ruffe, Round Goby) and Other Weeds (Curlyleaf Pondweed, Water Hyacinth, and Hydrilla). We found twenty-seven studies on economic impact of AIS in the Upper Midwest region and a majority of these (33%) were on Zebra Mussels. From this review of the literature we conclude that AIS have net negative impacts on society but measurement of these impacts is a challenging task as it depends on several factors including: ecological characteristics and relationships between the AIS and the native ecosystem, interactions between human activity and AIS and costs/benefits of these AIS which can be user-specific and costs of prevention versus management which can vary with AIS, location, agency and type of action.

This report is intended to summarize a literature review on the economic costs and benefits of invasive species in freshwater bodies. 125 papers on invasive species were examined in total, among which 108 dealt only with aquatic invasive species including marine species (AIS). 81 of these papers (about 75%) were based on water bodies and invasive species in the United States. From our study, we found that AIS have net negative impacts on society manifested through various channels like impact on native species which may be commercially valuable, damage to industrial systems like water pipes, damage to ecosystems like lakes and rivers, and losses accruing directly to users and non-users like losses in recreational and property values. 37% (of total) of the studies examined provide dollar values on different types of economic impacts of AIS but very few of these (about 19%) are from the Upper Midwestern region of the US, which is our area of interest. For example Pimentel (2005) suggests that the Great Lakes region faces $5.7 billion annually in costs associated with aquatic invasive species. Millions of dollars in public funds are spent annually to control AIS.

Part 1 of this report is divided into nine sections. In the next section, we classify existing research on AIS in several ways for convenience of analysis and to inform policy options. In the six sections that follow, we examine the classification by species in more detail and describe insights from studies on each species class examined.

Study Organization We categorized the reviewed studies in several ways to study and compile the work done in a meaningful way. Some important classifications were related to: (a) location; (b) subject focus; (c) provision of dollar values on economic impact; and (d) species/pathway. In terms of “location’, our analysis included any study on AIS on any place in the world but classified them as “Upper Midwest” and “Not Upper Midwest” to highlight studies that focused on Minnesota, Wisconsin, Michigan and/or more generally, the Great Lakes area. We found a small number of studies, about 38 that focused on the Upper Midwest. The studies classified by species, area and type are summarized in Table 1 in the Appendix.

We broadly categorized the papers into “Economic’, “Ecological’, “Descriptive” or “Management” depending on their focus, analysis and content. Economically and ecologically focused studies comprised papers with theoretical and empirical analyses or both. Although ecological studies provide useful insights into impacts of AIS and possible control actions, our analysis here focuses on existing economic research and hence we further categorized all our studies into “Economic” and “Non-Economic’. Among the 108 papers focusing on AIS, 46 provided estimates on economic impact but only 20 of these were from the Upper Midwest region. These estimates varied by definition of economic impact (control cost, economic damages, economic and environmental damages, property value reduction, and cost and benefits to anglers) and also by location and type of AIS involved.

The type of methods used by these studies ranged from aggregating measures from previous studies using a comprehensive review of the literature on economic impacts (Annual economic and environmental damages of invasive species: $120 billion/year of aquatic weeds and fish: $1.11 billion/year; (Lovell et al. 2006, Pimentel et al. 2002, 2005)), hedonic analysis for estimating reductions in shoreline property values (average annual cost of Milfoil infestation in Wisconsin lakes=$187,600 which means a 13% reduction in property values per year, (Horsch

and Lewis 2009), numerical analysis to estimate cost of using alternative management methods due to legislation banning a current chemical used for Milfoil control ($16.6 million for banning 2-4-D, NAPIAP report, 1996), statistical analysis and I-O models to estimate economic benefits of aquatic invasive species to fisheries and to anglers (sales in area increased by 15% when vegetation was at half-peak or peak levels compared to baseline-no vegetation-clear lake, (Kirk and Henderson 2000)), surveys and econometric choice models to quantify angler preferences and estimating willingness-to-pay (WTP) to control aquatic invasive species (WTP for Florida residents: 12.26 million/year to control AIP, Adams et al. 2010) and finally a study examining the willingness to accept (WTA) of consumers to pay for Asian Carp for human consumption as a method of carp control, (Varble and Secchi 2013).

Theoretical economic papers examined look at optimal management policies in the face of invasion risk assuming management actions are costly (Haight and Polasky 2010), propose alternative approaches to reduce invasion risks for example a tradable permit scheme or trade regulations to reduce invasion through ships ballast (Batabyal 2007, Horan and Lupi 2005) and models that propose interdisciplinary frameworks to combine economic and ecological damages (Shogren and Tschirhart, 2005). These models provide valuable insights on what should be accounted for in the scope of economic impact of AIS.

While our focus is studies looking at economic impact of AIS, these economic impacts cannot be understood or quantified accurately without understanding the ecological impacts of invasive species. Consequently we also examine papers studying ecological impacts of AIS using ecological modeling and surveys and providing insights about how these impacts should inform policy alternatives. In this category there were studies that examined the ecological (behavioral and anatomical) features of invasive species that made them significantly different from native species in being able to grow and spread in an area and of modifying the corresponding species communities and ecosystems (Toft, 2000), studies examining effectiveness of biocontrol agents like the Milfoil weevil in controlling Milfoil (Reeves, 2008), or Triploid Grass Carp in controlling Hydrilla (Manuel et al. 2013), studies examining risk potential of specific invasive species through their life cycle using spatial and ecological models (Masin et al 2013) and those that propose a framework to measure both ecological and economic impacts (Barney et al 2013).

In terms of species/pathways studied, the AIS species that were most commonly studied were Eurasian watermilfoil (Milfoil) (20 studies), different Carp species (20 studies), Zebra Mussels (15 studies), followed by Hydrilla (8 studies), Sea Lamprey (5 studies), Curly-leaf Pondweed (4 studies), Water Hyacinth (2 studies), Crayfish (5 studies), Eurasian Spiny Waterflea (4 studies), Ponto-Caspian bloody red shrimp (2 studies), and fishes like Ruffe (2 studies), Lake Trout and Sailfin Catfish (1 study each). Based on this species distribution, we classified the total species studied into six major categories: Carp, Crustaceans, Milfoil, Mussels, Other Fish, and Other Weeds. This classification is summarized in Table 1. In the following sections of this report, we describe the contribution and insights of studies examining the six main species/pathways considered: Carp, Crustaceans, Other Fish, Milfoil, Other Weeds, and Mussels.

Table 1: Summary of studies by area, species pathway, and type Count of Species Column Labels Not Upper Upper Grand Row Labels Midwest Midwest Total Econ 34 27 61 Carp 2 1 3 Crustacean 1 2 3 Milfoil 3 3 6 Misc. 12 5 17 Mussel 3 9 12 Other Fish 6 6 Other Weeds 13 1 14 NonEcon 53 11 64 Carp 11 5 16 Crustacean 4 2 6 Milfoil 1 1 2 Misc. 19 3 22 Mussel 3 3 Other Fish 6 6 Other Weeds 9 9 Grand Total 87 38 125

Economic Impact of Invasive Carp Invasive fish as a group occupies 28% of the existing literature on AIS, by our review and carp occupies 65% of all AIS fish reviewed. Carp comprises various species of oily freshwater fish of the family Cyprinidae, a large group of invasive fishes native to Europe and Asia (Chistiakov and Voronova 2009). Consequently they can be classified into two main groups: European (Common) Carp and Asian Carp. The main species of Asian Carp considered invasive are: Grass Carp, Silver Carp, Black Carp, and Bighead Carp2. Carp are an important food fish in many parts of the world (including parts of Asia, Western Europe and Russia) and are also valued as ornamental aquarium fish like goldfish and koi, which explains their accidental and intentional introduction worldwide. Their habitat now extends from North America (Buck et al. 2010) to the Middle East (Khoshnamvand et al. 2012) and from Africa (Winker et al. 2011) to Australia (Taylor et al. 2012). Carp are considered invasive in North America owing to their potential in altering aquatic ecosystems, reducing water quality and affecting native species so that carp control is a substantial share of pest control funds in the US. In Europe, they are a popular “angling” fish3 and as control programs become more expensive, such considerations are becoming popular in North America as well4.

Ecological Characteristics: Carp typically grow fast, spread rapidly and are able to alter ecosystems from both predation and competition with native species (Diggle et al. 2011, Winker et al. 2011, Dibble and Kovalenko 2009). Asian carp like Grass Carp are known to reduce natural vegetation, which affects the ecology of aquatic ecosystems (Pimentel et al. 2005). For common carp, a noted ecological trait is bioturbation-stirring up sediments and processed food from the lake floor during feeding that reduces water quality, impedes water-based recreation (Pimentel et al. 2005, Weber and Brown, 2009, Arlinghaus and Mehner, 2002) and can even lead to eutrophication from more cyanobacterial colonies (Adamek and Marsalek 2013). Common carp affects the entire aquatic ecosystem by a combination of bioturbation, benthic foraging and

2 http://www.invasivespeciesinfo.gov/aquatics/asiancarp.shtml

3 http://www.carp-uk.net/

4 http://www.americancarpsociety.com/

competition (Weber and Brown 2009). According to the Great Lakes Fishery Commission, Asian carp populations could expand rapidly and change ecosystem composition for the Great Lakes, mainly due to their various diets: silver carp eat phytoplankton, bighead carp eat zooplankton, black carp eat invertebrates such as snails and mussels, and Grass Carp eat aquatic plants. They also pose a serious threat to native species like fishes, mussels and aquatic invertebrates through competition and habitat modification. However, among all species of Asian Carp, only Grass Carp have the potential for establishment in the Great Lakes (Buck et al. 2010).

Economic Costs: The main negative impacts of carp come from reduction of water quality (Weber and Brown, 2009) and reduction in commercially valuable fish species. However, carp, specifically Asian carp is also used as a biocontrol agent for aquatic weeds (Dana et al. 2013) in the US and as a popular “angling” fish in Europe (Arlinghaus and Mehner 2002). Though more than half of our reviewed studies are on the Upper Midwest region, none of these provide economic impact figures for carp. One study provides costs for building electric dispersal barriers for preventing carp entry into Lake Michigan as $23 million. The study also quotes the amount requested in the federal budget for building electric dispersal barriers as $7.25 million for 2011 (Buck et al. 2010). Water quality being a valuable ecosystem service, we examined the corresponding economic literature to get an estimate of its value specifically for lake users. (Egan et al. 2009) report findings from an econometric model on lake usage based on various water quality measures: clarity, loading of various nutrients like N and P and chlorophyll, based on data on lake characteristics and a survey of lake users in Iowa. Their results indicate that lake clarity is very important to lake users. High nutrient concentrations were found to decrease lake trips though respondents did not seem to mind the presence of chlorophyll. The average price of a lake trip based on travel cost was found to be $135 while the willingness-to-pay (WTP) for improved water quality for all lakes in study (128) was found to be $151 per household, with a potential of increasing lake trips by 3.3% annually. They also find that improving a few lakes also has positive economic benefits: $19 per household. These results suggest a possible method of evaluating the loss in recreational value from reduction in water quality from a common carp infestation.

The only two studies providing economic impact figures for carp, are from Germany and Egypt. In Germany, where carp angling is popular, Arlinghaus and Mehner (2002) used a contingent valuation approach to find that net economic value or consumer surplus of common carp angling was about 1000 euros per angler per year ($1358.70). A more recent study in Egypt provides an economic benefit estimate for Grass Carp as an effective biocontrol agent for aquatic weeds (Ahmed et al. 2012). The costs of aquatic weeds do not comprise just recreational loss in Egypt but include excessive water use, spread of disease through pests, damage to infrastructure like bridges and reduction in agricultural yields. Not surprisingly, the net present value of a Grass Carp hatchery was found to be 407.3 million pounds (about $668 million) with a benefit- cost ratio of 3,230 and a payback of just one year.

Control Strategies: Carp are usually controlled by chemical treatment or physical harvest (Buck et al 2010, Bajer et al. 2011), but Varble and Secchi suggest an unconventional method: human consumption (Varble and Secchi, 2013) for Asian Carp. Using a national survey of US consumers, they find that most respondents would be willing to pay for carp as a restaurant entrée making human consumption a market-based, cost-effective solution to control carp in the Great Lakes. Another method used for carp control is the placement of electric barriers at the mouths of rivers to prevent entry of Asian carp into the Great Lakes (Buck et al 2010). For Common Carp, physical harvest through electrofishing or the Judas technique (using radio- tagged fish to locate and remove winter-time carp shoals-5-10 C) are effective measures employing ecological traits of carp with modern technology (Bajer et al. 2011 and 2012). Finally, in countries where carp is a popular sport fish valued for consumption, “carp angling” could be an effective means of carp control. Arlinghaus and Mehner (2002) show that common carp anglers” catch exceeds commercial common carp harvest by up to 2,500% suggesting that carp angling can reduce carp stocks efficiently provided best management practices are undertaken including education, risk communication and monitoring since carp angling may pose a eutrophication risk through phosphorus use in baits. The authors also provide a tool (simple equation) to managers for appraising the chance of a negative ecological impact from carp angling so that this sport can be optimized for generating benefits as well as managing carp stocks efficiently.

Several authors suggest incorporation of research, education and integrated methods and tools for understanding and determining the risk of invasive fishes and taking corresponding management actions. For Common Carp, bioturbation and ecosystem alteration is a serious concern. Weber and Brown point out that a policy of removing carp from infested waters to restore water clarity is not an effective restorative solution. Restoration efforts should focus on entire ecosystems (humans, habitats, and biota) in conjunction with common carp reductions to achieve the greatest success at minimizing the effects of common carp and to return lakes to the clear water state. The water quality study of the Six Mile Creek sub-watershed done by the Minnehaha Creek Watershed District is an example of such ecosystem-wide restoration efforts5. Dibble and Kovalenko, (2009) show that the ecological impacts of Grass Carp can be complex with changes taking place over species communities and over time and some of these phenomena may not be understood by current science. Hence ecological research on the impacts of Grass Carp should be an essential component of effective management strategies.

DeVaney et al. (2009) used ecological niche modeling (ENM) to predict the invasion potential and future distribution of four carp species in North America: Common Carp, Tench6, Grass Carp and Black Carp. They found that Common Carp will have a broad distribution all over the US while Grass Carp will cover extensive portions of the eastern, central, and northwestern US. Tench is predicted to occupy most of the upper Midwest and the eastern US and parts of the northwest. Black carp was predicted to occupy a much smaller area and only in the eastern US. The authors” opined that ENM can be an effective invasive species management tool as it predicted potential ranges of carp species correctly even in regions where the species have not been present until recently and the time required is within the short screening time required by proposed U.S. invasive species legislation (DeVaney et al. 2009). (Kulhanek et al. 2011) also used ENM with long-term monitoring data for Minnesota lakes to identify presence and explain abundance of common carp in Minnesota and South Dakota lakes. Their models correctly identified over 83% of carp sites and explained 73% of the variation in carp abundance for lakes in Minnesota and explained 32% of the variation in carp abundance for South Dakota.

5 http://www.minnehahacreek.org/project/six-mile-marsh-diagnostic-study

6 http://en.wikipedia.org/wiki/Tench

Variables related to climate and water quality were found to be the most important predictors of carp distribution.

Investigating the implementation of integrated tools on the policy front, we found that the Obama administration has released a plan called the Asian Carp Control Strategy Framework in 2010 outlining future actions and funding sources to eliminate the threat of Asian carp in the Great Lakes. This plan identifies 25 short- and long-term actions and $78.5 million in new funding to implement these recommendations (Buck et al. 2010). This is part of a larger initiative: the Great Lakes Restoration Initiative (GLRI), funded currently at $300 million per year, delegated to address the most significant problems in the Great Lakes region, including the spread of Asian Carp. As regards Minnesota, Asian Carp is recognized as a significant threat to the state’s $4 billion boating and fishing economy. Consequently in May 2012, the Minnesota Legacy bill approved $7.5 million for research and construction of barriers for Asian Carp control while another $3.8 million was intended to help create an aquatic invasive species center at the University of Minnesota7. In June 2012, Minnesota senators Franken and Klobuchar helped pass the Stop Invasive Species Act, which would require a plan to block the entry of Asian carp into the Great lakes through several connecting rivers. They also introduced the Upper Mississippi Conservation and River Protection Act (Upper Mississippi CARP Act) to incentivize closing the Upper St. Anthony Falls Lock to help stop the spread of the invasive species, including Asian Carp8. The Minnesota DNR just announced this week (May 26th-May 30th, 2014) that the lock will be closed within the year9.

Economic Impact of Invasive Crustaceans Invasive crustaceans occupy 8% of the existing literature on AIS, by our review. The most commonly studied crustaceans were the Crayfish (5 studies among which two involved Rusty Crayfish), the Eurasian Spiny Waterflea (4 studies), and the Ponto-Caspian bloody red shrimp

7 http://stopcarp.org/links/

8 https://www.franken.senate.gov/?p=hot_topic&id=2249

9 http://www.kare11.com/story/news/local/2014/05/27/upper-st-anthony-falls-lock-to-close-within-a- year/9631965/

and the Green Crab (2 studies each). Crayfish are freshwater crustaceans resembling small lobsters and represent a large group of animals belonging to the superfamilies Astacoidea and Parastacoidea. Most crayfish like clean freshwater habitats with warmer temperatures though invasive varieties like the Procambarus clarkii, are more resilient. The AIS classification of crayfish is somewhat confusing as most of the crayfish species considered invasive in other continents, are North American varieties like the above. However, some species like the Rusty Crayfish (Orconectes rusticus) are regionally invasive as it has spread from its historical range in the Ohio River drainage to waters throughout much of Illinois, Michigan, Wisconsin and Minnesota and parts of 12 other states, Ontario, Canada, and the Laurentian Great Lakes (Olden et al. 2006). The Spiny Waterflea (Bythotrephes longimanus), native to northern Europe and Asia, is a tiny planktonic crustacean (about 0.6 inches long), widely distributed as an AIS in the Great Lakes region of US and Canada, since the 1980s, due to accidental introduction (Yan et al. 2011). By 2010, this species had been documented in many of the Great Lake states including Michigan, Minnesota, New York, Ohio, and Wisconsin. The Ponto-Caspian bloody-red shrimp/mysid (Hemimysis anomala) is a shrimp-like crustacean native to the Ponto-Caspian region, which is now considered an AIS in both Europe and the North American Great Lakes10. Finally, the Green Crab (Carcinus maenus), a common shore crab, is an important marine and estuarine AIS (listed as the IUCN world’s 100 worst invasive species11). It is native to the northeast Atlantic Ocean and the Baltic Sea but has spread to Australia, South Africa, South America and both the East and West coasts of North America.

Ecological Characteristics: All invasive crustaceans are bottom feeders and can restructure species communities on the lake floor through competition and predation. For example, the spiny waterflea consumes about 10-20 zooplankton (including Daphnia and smaller crustaceans) per day and competes with several fish species like yellow perch, panfish and larval fish for zooplankton. Zooplankton being a key element in aquatic food chains, the spiny waterflea can cause serious ecosystem level changes in the Great Lakes including depletion of zooplankton stocks and decline in commercially valuable fishes (Barbiero and Tuchman, 2004). The spiny

10 http://www.glerl.noaa.gov/res/Programs/glansis/hemi_brochure.html

11 http://www.issg.org/database/species/search.asp?st=100ss&fr=1&sts=

waterflea also has evolutionary features that increase its invasion potential. For example, the barbs on their body discourage predation by fishes and their eggs can survive even after being dried out or eaten by fish (Barbiero et al. 2004). Additionally, green crab and invasive crayfishes can tolerate a variety of salinity conditions and so can spread in both freshwater and saltwater environments (Lafferty and Kuris, 1996, Sousa et al. 2013). Invasive crayfishes can also transmit the disease crayfish plague, fatal to native crayfishes (Capinha et al. 2013). The Ponto-Caspian bloody red shrimp was found to have higher predatory responses compared to native shrimp species through an inter-regional ecological experiment in Ireland and Canada (Dick et al. 2013).

Economic Costs: Invasive crustaceans like the spiny waterflea, crayfishes, crabs and shrimps lead to economic costs mainly by preying on native species and competing with commercially valuable species by affecting their prey base (Barbiero, 2004) and modifying their habitat (Capinha, 2013). Estimates of economic impact for invasive crustaceans are scarce going by our review. We did not find any economic impact figures for the crayfish, spiny waterflea or the bloody red shrimp. We found one study that estimates economic impact for only one species: the European Green Crab-Lafferty and Kuris (1996) find that biologically controlling the European Green Crab using the parasitic barnacle Sacculina carcini provide estimated benefits of $22.8 million for fisheries in northern and central California, $4.9 million for those in southern California, and $59 million for Puget Sound for 1990-1991. However another study in 2013 actually documented a benefit from the green crab: (Bertness and Coverdale 2013) showed that the green crab reverses decades of degradation in the salt marshes of New England by preying on the herbivorous crab (Bertness and Coverdale 2013) and by replacing natural salt marsh predators eliminated through human impacts like overfishing. They do not quantify these benefits as a dollar value.

Control Strategies: The main method for controlling invasive crustaceans like crayfishes, crabs and shrimps, is through biological control using parasitic barnacles for crabs (Lafferty and Kuris, 1996) and Triploid Grass Carps for crayfishes (Jordan, 2003). There is currently no management method directed at the spiny waterflea though it is known that they are sensitive to warmer water

temperatures (die at 25C and above) and even have an Allee12 effect to their disadvantage (Kim and Yan 2010). This means climate warming can ultimately eliminate their spread in the Great Lakes region (Yan et al. 2011). In terms of long term control strategies, experts advise examining the determinants of invasive crustaceans” spread through research and formulate a combination strategy of risk assessment, prevention and early detection. For example it is known that propagule pressure13, through human recreational activity and fishing is a key determinant of the spread of invasive crustaceans so that monitoring these activities could yield measurable benefits (Yan et al. 2011, MacIsaac et al. 2002). (Capinha et al. 2013) used species distribution models and spatial data to study the effect of climate change, future watershed boundaries and invasive crayfishes on the future distribution of the threatened European Crayfish and found that native crayfish’s habitat would decrease by 19-72%, overlap with the invasive crayfish would increase, and that the habitat of the invasive crayfish is likely to increase in the middle and end of the 21st century. These results underscore the importance of preventing new AIS introductions to reduce interactions between climate change and AIS while suggesting assisted colonization for predicted suitable areas for native species.

Economic Impact of Other Invasive Fish Invasive fish as a group occupies 28% of the existing literature on AIS, by our review. There are a variety of fish considered invasive in some freshwater systems, for example different kinds of Carp, Snakeheads, Sea Lamprey, Largemouth Bass as shown by the following list14. Pimentel et al. 2005) provides a derived measure of $5.4 billion for economic loss from invasive fishes based on the $69 billion annual contribution of the sports fishing industry to the US economy. However in terms of directed economic research only a few of the AIS fish reviewed here have had their individual economic impacts studied. After Common and Asian Carp, these fishes are: Sea Lamprey (5 studies), Ruffe (2 studies), followed by Lake Trout, the aquarium fish Sailfin Catfish, and Round Goby (1 study each) and two general studies on invasive fish.

12 http://en.wikipedia.org/wiki/Allee_effect

13 http://en.wikipedia.org/wiki/Propagule_pressure

14 http://en.wikipedia.org/wiki/List_of_invasive_species_in_North_America

Invasive fish are important to AIS management due to two main reasons: (1) they comprise the second largest group of AIS (next to AIP), and (2) their introduction worldwide has allowed inter-temporal changes to ecosystems over time with socioeconomic impacts. Given introduction frequency, adaptability of AIS and the length of time they grew undisturbed, these fish were able to change species and ecosystem characteristics of the corresponding non-native environments as Marr et al. 2013, finds for the 136 AIS fish in the Mediterranean Sea. Here we examine the impacts of Sea Lamprey, Ruffe, Lake Trout, Sailfin Catfish and Round Goby.

Sea Lamprey: The Sea Lamprey ( Petromyzon marinus) is a parasitic lamprey found in the northern Atlantic Ocean, along shores of Europe and North America, in the western Mediterranean Sea, and in the Great Lakes. It is not technically an AIS since it has been in these habitats for a very long time, before the time of humans. However its dispersal is facilitated by navigation, maritime trade and improper disposal of fish remains after anglers clean the caught fish. Lampreys are considered delicacies in parts of Europe but are not commonly consumed in the US. They are managed as AIS in the Great Lakes, the only place where they are found in the US.

The Ruffe (Gymillionocephalus cernuus) is native to Europe and Asia and is of major concern as a North American AIS, especially for the Great Lakes region. Lake Trout (Salvelinus namaycush) is actually a freshwater char native to northern North American lakes including the Great Lakes. They were accidentally introduced into Yellowstone Lake in Wyoming, where they are now considered invasive and in competition with the much smaller native Cut-Throat Trout. The Sailfin Catfish (Pterygoplichthys multiradiatus) is a tropical fish native to South America, Panama and Costa Rica (Capps and Flecker, 2013). It belongs to the armored catfish family (Loricariidae) and named for its sail-like and “many rayed” dorsal fin. It is of major concern as AIS in rivers worldwide as a result of accidental introduction through the aquarium trade (Capps and Flecker, 2013). The Round Goby (Neogobius melanostomus), is a small, soft-bodied fish with a black spot on the first dorsal fin, that is native to central Eurasia including Black Sea and Caspian Sea. It was accidentally introduced in the Great Lakes through ballast water transfer of cargo ships and is of major concern as an AIS due to its significant ecological and economic impact (Corkum et al. 2004). 12 of the 31 papers in our study concern the Upper Midwest region

including the Great Lakes while the remaining studies are from Arizona and Nevada, Yellowstone Lake, Wyoming, Europe in general, Ireland and Canada, the Iberian peninsula, the Mediterranean regions, the Chacamax river in Mexico, Africa and Australia.

Ecological Characteristics: The common ecological characteristics of most AIS fish are that they grow fast, spread rapidly, are bottom-feeders and are able to alter benthic ecosystems through plankton predation and competition with other native species (Winker et al. 2011, Dibble and Kovalenko, 2009). This applies to all types of carp, goby, catfish as well as lampreys. Lake trout is a special case here as they take a long time to mature and do not have AIS features except in Lake Yellowstone (Ruzycki et al. 2003). In fact, lake trout have been commercially fished in the Great Lakes before their populations dwindled owing to lamprey infestations, overfishing and pollution15.

Economic Costs: The economic costs of invasive fish are mainly from damage to native species that are commercially valuable for example effect of sea lampreys on Great Lakes fish. In these cases, the most common method of estimating economic impact is measuring the benefits of increased native fish populations to recreational and commercial anglers, by controlling the invasive fish species. We found only three studies with economic impact figures for fish other than carp and these were on sea lamprey and ruffe. Sturtevant and Cangelosi, (2000) report the benefits of a lamprey control program to be $2.1-$4.3 billion/year for the Great Lakes region. Jenkins, 2001 provides estimates of controlling lamprey in the US and Canadian Great Lakes as $13.5 million/year. Lupi et al. 2003 estimate the annual benefits from a lamprey control program in the St. Mary's River, Michigan, as $300,000/year. They also predict a benefit estimate of $3.2- $5.8 million for 2015. In the same spirit, Leigh (1998) provides an estimate of the annual benefits to the Great Lakes fishery (mainly sportfishes: yellow perch, walleye and whitefish) of a Ruffe control program as $13.6 million. He predicts that the benefit cost ratio to the public of this control program over 5 future decades is 44:1.

15 http://en.wikipedia.org/wiki/Lake_trout

Control Strategies: The most common control method for invasive fish species is chemical treatment. For example, for sea lamprey, the main method is treating streams in the Great Lakes basin with the lampricide TFM (3-trifluoromethyl-4-nitrophenol), which kills larval sea lamprey before they can migrate to the Great Lakes (Lupi et al. 2003). However, two other control methods were applied in Lupi’s study for the St. Mary’s river as higher volume of flow and expensiveness of TFM made its application limited (Shen et al. 2003). The two methods applied were (a). Sterile male release and trapping (SMRT) and (2). Granular Bayluscide applications (GB). SMRT reduces reproductive potential by trapping males and females, destroying the females, sterilizing the males, and releasing them to compete with the remaining non-sterile males. This is done annually to keep sea lamprey populations suppressed. GB is a chemical treatment that kills larval sea lamprey, which is usually repeated every five years for best results (Schleen et al. 2003). Ruffe can be effectively controlled using the lampricide TFM (Leigh, 1998). Research on invasion potential and prediction of future habitat for invasive fish, is important for cost-effective policy. For example, Almeida et al. (2013) propose, develop and apply a risk identification tool called FISK (Fish Invasiveness Scoring Kit), to successfully determine the invasive potential of 89 fish species for the Iberian peninsula, a region important for freshwater fish conservation. This tool has been recently improved (FISK v2) to facilitate identification and scoring in all climatic zones and Puntilla et al. (2013) have applied it successfully in northern Europe, which means the tool should be transferable to examine invasion risk of specific fish species in North America as well.

Economic Impact of Invasive Mussels According to our review, different kinds of invasive mussels occupy about 16% of the existing literature on AIS. The most common invasive mussels studied are the Zebra Mussel followed by the Quagga Mussel. We also found one study on the Golden Mussel and a few on the Asian Clam, which we included in the “Mussel ” category (as all of them are bivalve mollusks) for simplicity. The Zebra Mussel ( Dreissena polymorpha) is a small freshwater mussel that typically has a stripe patterned shell. The species was originally discovered in Russian lakes in the 18th century and is still found in nearby areas like the Black Sea and the Caspian Sea (It is a Ponto- Caspian species). The Zebra Mussel was accidentally introduced in many other areas which led

to its spread as an invasive species across the world including the US. From our study, it seems most of the Zebra Mussel concentration is in the Upper Midwestern states (Johnson and Meder, 2013) and the Great Lakes region of the US (Hushak et al. 1995) though they are also reported in the eastern US (Wick, 2013) and the Pacific Northwest (USACE, 2009). The Quagga Mussel (Dreissena rostriformis bugensis) is another subspecies of freshwater mussel native to the Dnieper River in Ukraine. It also has a striped shell but unlike the Zebra Mussel, its stripes fade out towards the ventral side. The Quagga Mussel is currently of major concern in the US as an AIS (48 and 55) and two of the papers in our review, studied their presence and impacts in Lake Champlain (shared between eastern USA and Canada, Bering et al. 2013) and in the Columbia river basin in the Pacific Northwest, USA (Warziniack et al. 2013). The Golden Mussel (Limillionoperna fortunei) is a medium-sized freshwater mussel native to China which is now an AIS in South America, where it was accidentally introduced. The site of one of our reviewed studies on the Golden Mussel is based on the Rio de la Plata river in Argentina (Sylvester et al. 2013) while another (Oliveira et al. 2010) forecasts that it could spread to the Rio Grande river in Brazil and even to the Mississippi and Colorado rivers in North America. The Asian Clam (Corbicula Fluminea) is a small freshwater clam species native to Africa, Australia, and southern Asia, and now of increasing concern as an AIS in Europe (Hyytiäinen et al. 2013) and in many lakes, streams, rivers and canals, in the US including Lake Tahoe (USACE, 2009). We did not find any studies in the Upper Midwest or Great Lakes region on the Asian clam or on the golden mussel.

Ecological characteristics: All AIS in the “mussel” category have some common ecological traits. For example, they are mainly “filter feeders’, feeding on plankton in the water column and depositing processed food and non-food particles on the lake floor. While this improves lake clarity, it also leads to higher macrophyte growth in lakes due to higher sunlight penetration. These bacteria, when decaying wash up on shores causing water quality problems and being an aesthetic concern for beachgoers (Minnesota DNR, 2010). They can also attach to a variety of substrates using strong “byssal” threads attached to their dorsal side. This also leads to clogging (water pipes) problems and consequent cleanup costs for homeowners or industry when water infested with these AIS is used to water lawns or for industrial purposes like cooling systems for power plants or nuclear reactors (Leung et al. 2002). Some additional problems could be cuts to

beachgoers” feet, and damage to property like boats, swim rafts, ladders and fishing line from large and sharp mussel shells. The damages to fishing line could lead to loss of fishing tackle for anglers. All of the above AIS also suppress comparable native species either through competition or by attaching on them directly for example: Zebra Mussels can attach to native mussels, killing them. Another ecological trait that facilitates the spread of these invasive mussels is their ability to reproduce and grow rapidly. Zebra and Quagga Mussels have low tolerance to high temperatures and high salinity levels (Bering et al. 2013) while Asian clam and golden mussel (Karatayev et al. 2010) are more suited to higher temperatures and more saline systems (See USACE 2009, Appendix, page 99 for details). Effect of filter feeding mussels on non-mussel species is mixed. For example by filtering plankton, Zebra Mussels can increase lake floor food supplies for mature fish species like yellow perch (Lake St Clair, Sagoff 2003) but can reduce food supply (plankton) for larval fish thus again being a concern for anglers.

Economic Costs: The main economic costs attributed to invasive mussels is cleanup costs from clogged water pipes in homes and industry, damages to industrial facilities like power plants and drinking water systems, damage to boats, docks and piers, damage to cultural or historical objects like Great Lakes shipwrecks (Bering et al. 2013), fouling of beaches, and loss of commercially valuable native species like fish. All but one of the papers estimating economic costs of Zebra Mussels in our review are from the Great Lakes region and they all estimate control costs for mussel cleanup for water-use facilities. The most recent estimate of control cost for Zebra Mussels is $5.2 million/year for Lake Champlain (Bering et al. 2013). For the other five great lakes, the most recent estimate of economic cost from Zebra Mussels (from our review) is $149 million for a study period of 6 years (1989-1994) or $37 million/year between 1992 and 1994 (about 60 million/year for 201316) for the Great Lakes region (Park and Hushak, 1999). This study focused on the control cost of Zebra Mussels by chemical treatment using data from surface water-using facilities in the Great Lakes region like electric utilities, water treatment plants and golf courses. Some of the other figures seem to have high variance: for example O’Neill’s (1997) National clearing house study on Zebra Mussels control costs produced an estimate of $21.5 million/year for 1995; also Sun (1994) found control costs for

16 Calculated based on the Consumer Price Index (CPI for 1992, 1994 and 2013). 22

Zebra Mussels to be $6.2 billion over 10 years while two years later Catoldo (1996) found such costs over 10 years to be $3.2 billion. However Park and Hushak’s estimate of $37 million/year is closer to Catoldo’s estimate of $3.2 billion over 10 years. We did not find any study explicitly on the Quagga Mussel but Warziniack et al. (2013) finds that without preventative efforts, threat of a Zebra or Quagga Mussel invasion would cause an expected annual $3.2 million welfare loss in the Columbia river basin in the Pacific Northwest. This figure includes losses incurred to recreational activities like boating, fishing and industries like power plants. Also, (Bering et al. 2013) finds that power plants and water supply facilities in the Great Lakes region face an estimated $500 million in damages annually due to zebra and Quagga Mussel problems. We did not find any study exclusively on Asian clams that provided estimates of its economic impacts. However, Wick 2013 studied economic impacts of several AIS in Lake George, NY and provides an estimate of the management costs for an Asian clam infestation in Lake George to be $1,500,000 over two years. We did not find any estimate for controlling the Golden Mussel from the literature reviewed.

Control strategies: The most common methods of controlling invasive mussels is chemical treatment, physical harvest with scuba divers or mechanical suction harvest, and the use of benthic mats, flexible mats placed on the lake floor to block sunlight and prevent growth of targeted AIS. The Lake George study reports the use of all of these treatments for Zebra Mussels and Asian clams (Wick 2013). Though these methods usually work for Zebra Mussels and Asian clams, controlling Quagga Mussels is more difficult as once established, their larvae float throughout the water body and are well-dispersed (Bering et al. 2013). Chlorinating water and raising water temperatures have been shown to cause high mortality levels in Quagga Mussels (Brady et al. 1996). These methods can harm native ecosystems and are therefore not viable in large lakes but they can be applied in a boat lift or when rinsing boats after transport between water bodies (Beyer et al. 2011).

As invasive mussels have spread to many areas in the US, especially the Great Lakes, several authors have proposed more integrated approaches to their management: for example Finnoff et al. (2005), propose an integrated bioeconomic framework to study Zebra Mussel infestation in a Midwestern lake that affects a local electricity generation facility. They examine the impact of removing two feedback loops: one between the firm and the biological system, i.e. the lake, and another between manager and firm and conclude that accounting for these feedbacks can make 23

managing invasion risk more cost-effective for both private and social utility maximization contexts. As risk of invasion is often a function of trade, specifically exports, Warziniack proposes public economic tools, i.e. taxation as a control strategy for mussels in the Columbia river basin, where the tax is either a visitor tax to prevent invasion or an import duty (pertaining to trade between residents of the basin and non-residents) to reduce invasion risk because due to high elasticity of tourist demand curves, export taxes will not have much impact on invasion risk.

Economic Impact of Milfoil Eurasian watermilfoil ( Myriophyllum spicatum) is a vascular AIP originating in Europe and Asia that has invaded many freshwater lakes in the US (Turnage et al. 2013). By our review, it is the most common aquatic invasive plant (AIP) studied, occupying 63% (20 studies) out of all AIP (32 studies).

Ecological Characteristics: The invasiveness of Eurasian watermilfoil (Milfoil) is facilitated by its advantageous ecological traits over comparable native species including rapid growth and dispersal levels and high adaptability. Eurasian watermilfoil can grow in a variety of aquatic habitats ranging from freshwater lakes to brackish estuaries, can tolerate high levels of salinity and alkalinity (hard water) and a large number of trophic states. The dense underwater canopy of mature Milfoil can impede boating, swimming, fishing and other aquatic activities. It also has negative impacts on native plants (Madsen et al 2008), and can cause ecosystem level changes by altering the equilibrium between predators (bass) and their prey (Madsen, 2005). Interactions between Milfoil and other AIS like crayfish are likely to aid Milfoil dispersal (Maezo et al. 2013).

Economic Costs: The main socioeconomic costs imposed by Milfoil arise from its invasion of water bodies, especially lakes and rivers impeding navigation, water-based recreation, reducing amenity values for shoreline property owners, out-competing native species (which may/may not be commercially valuable) for dissolved oxygen and other nutrients, and finally costs incurred in controlling it. The literature reviewed finds six studies on Milfoil containing economic impact figures but only three of these are from the Upper Midwest or the Great Lakes region. Most of the estimates for economic costs/impacts were obtained through stated preference surveys like

contingent valuation designed to capture the willingness-to-pay (WTP) for a lake free of Milfoil while a few were based on hedonic price models which estimated the loss of amenity value for shoreline properties. Halstead et al. (2003) find from a study of selected lakes in New Hampshire, that shoreline property values can drop by 20% to 40% when the corresponding lake is infested by Milfoil. Horsch, and Lewis (2009) find that for lakes in Wisconsin, property owners are willing to pay on average $28,000-$32,087 for a property on a lake free of Milfoil and that the aggregate cost of Milfoil is $187,600/year on average for one additional infested lake. This amounts to an annual drop of 8% in property value (13% in land values) due to Milfoil infestation. Provencher et al. (2012) finds similar estimates for per property welfare loss from potential lake invasion in northern Wisconsin by Milfoil: $23,614-$30,550. Frid et al (2013) finds the value of recreation lost from Milfoil infestation of lakes in British Columbia, Canada, as $954.95 per hectare infested in 2006.

Control Strategies: Once established, Milfoil is very hard to control or remove (Woolf and Madsen, 2003; Turnage et al. 2013). Chemical treatment is the most commonly used method for controlling Milfoil using herbicides like 2,4-D, fluridone and triclopyr (Lembi, 1996) but other available methods are: Physical control (e.g. shading or dredging to decrease available light) harvest, mechanical harvest (using hand harvesters or aquatic harvesters), and biocontrol (Madsen 2005) through native insects like weevils, a native pathogenic fungus, fish like Grass Carp and GMO fish like Daughterless Carp (Dana et al. 2013). Among these Grass Carp are controversial as they are themselves an AIS and reduce lake clarity (Weber and Brown, 2009), do not seem to prefer Milfoil as food (Madsen 2005) but have been used to control Hydrilla. Managers also have concerns about GM techniques like Daughterless Carp mainly due to their lack of use and potential effect on native species. Reeves et al. (2008) find substantial variability in the efficacy of the Milfoil weevil to control Milfoil in 30 Michigan and Wisconsin lakes.

Economic Impact of Other Invasive Weeds A substantial percentage of the existing literature on AIS is focused on aquatic invasive plants (AIP) or aquatic weeds according to our review (33%). This is not surprising given AIP is a significant proportion of AIS worldwide and the 100th worst invasive species just named by the International Union for Conservation of Nature (IUCN) is giant Salvinia, an aquatic fern (Luque

et al. 2013). The most common AIP studied apart from Eurasian watermilfoil, are Curly-leaf Pondweed, Hydrilla and Water Hyacinth. Curly-leaf Pondweed (Potamogeton crispus), widely sold as an aquarium plant in the US and now spreading in lakes and rivers in midwestern and eastern US, is a native of Europe, Africa, Australia and Asia. Hydrilla ( Hydrilla verticillata), also native to Europe, Asia, Africa, and Australia, is now of increasing concern as an AIP in Florida and southern US in general while Water Hyacinth (Eichhornia crassipes), an ornamental plant is spreading in Florida as well as California (Toft, 2000).

Ecological characteristics: The ecological literature suggests that all of these weeds have common ecological characteristics that enable them to colonize large areas within a short time, suppress native species and impede recreational activities like boating and fishing. These features are: high growth rates, high reproduction rates, dense underwater canopies or mats, high adaptability to a variety of nutrient and trophic levels and geographic areas and harsh climates in stark contrast to native species. Water hyacinth or E.Crassipes, a native of the Amazon basin is documented to have significant ecological and socioeconomic impacts in areas of introduction (Villamagna and Murphy, 2010). Similar to Milfoil, Water Hyacinth has ecological traits that facilitate its invasiveness. For example, Fan et al. (2013), found that the overall resource use efficiency for water hyacinth was different compared to an analogous native plant and increased with higher nutrients in the environment suggesting the invasiveness of E. Crassipes increased with higher resource availability making the native species more vulnerable.

Economic costs: The main socioeconomic costs imposed by AIP arise from their invasion of water bodies, especially lakes and rivers impeding navigation, water-based recreation, reducing amenity values for shoreline property owners, out-competing native species (which may/may not be commercially valuable) for dissolved oxygen and other nutrients, and finally costs incurred in controlling them. The literature reviewed provides evidence of substantial economic costs from AIP. However, only four of these studies are specific to the Upper Midwest or the Great Lakes region. Most of the estimates for economic costs/impacts were obtained through stated preference surveys like contingent valuation designed to capture the willingness-to-pay (WTP) for a lake free of AIP while a few were based on hedonic price models which estimated the loss of amenity value for shoreline properties. For example Rockwell (2003) estimates that the annual

loss from aquatic weeds like Milfoil and Hydrilla, is $10 billion to the US while Bell et al. (2004) find that aquatic weeds, especially Hydrilla in Lake Tarpon cost the state of Florida $857,000/year in lost recreational value. Eisworth et al. (2005) compute annual economic impact of wildlife-related recreation from AIP in Nevada to be $6 million-$12 million. They also provide the present values of discounted impacts over 5 years as $30 million-$40 million in Nevada depending on actual future expansion rates of weeds. Some of these costs seem to be user dependent and may count as benefits although not explicitly quantified. For example, a recreation-user based economic study by Henderson (1995) in Lake Guntersville, Tennessee found that 47.1% of boat anglers view aquatic plants as a help to their recreation experience while the majority of other recreation users thought plants had no effect and about 25% of bank anglers said plants were “bothersome at least part of the time'. Also according to Bell et al.’s (1998), study of aquatic weeds, mainly Hydrilla, in Lake Tarpon, Florida, 50% of lake users surveyed said aquatic weeds were a serious problem while one in four said that they were “good for fishing’. According to information provided by the Minnesota DNR, Curly-leaf Pondweed “provides some cover for fish; several waterfowl species feed on the seeds; diving ducks often eat the winter buds’17.

Control Strategies: Research on AIP shows that once established in water bodies, they are very hard to control or remove (Woolf and Madsen, 2003; Turnage et al. 2013). Madsen (2005) reports four available control methods for AIP: Physical control (e.g. shading or dredging to decrease available light) harvest, mechanical harvest (using hand harvesters or aquatic harvesters), chemical treatment (using herbicides like 2,4-D, fluridone and triclopyr) and biocontrol through native insects like weevils, native pathogenic fungi, fish like Triploid Grass Carp (Manuel et al. 2013) and Daughterless Carp (Dana et al. 2013). In defense of herbicides as the most cost-effective method, Lembi (1996) estimates that total annual cost to society on alternative management of aquatic weeds due to loss of the weed killer 2,4-D from the market: $16.6 million.

17 http://www.dnr.state.million.us/invasives/aquaticplants/curlyleaf_pondweed.html

Given the complexity of AIP invasion, their effects on humans, other species and ecosystems, and the difficulty in controlling them, several authors have proposed formulating systematic management strategies and action plans to tackle them. They have also proposed estimating the costs of implementing such plans versus the risk of invasion to determine their feasibility. For example Barney et al. (2013) propose a quantitative framework to measure ecological impacts of invasive species integrating impact metrics as functions of groundcover and geographic extent. Mehta et al. (2007) show that there is a tradeoff between difficulty and benefits of optimal detection where the optimal detection strategy depends on the biological relationship of each species. Plans specifically directed at specific lakes like the AIS management plans for Lake Tahoe and Lake George (USACE, 2009 and Wick, 2013) combine economic impact figures for AIS (including AIP) and recommend comprehensive strategies to manage them through early detection strategies like mandatory boat inspection, prevention of future reintroduction, research, and education. Managers should also keep in mind that the probability of future AIP invasion depends on lake characteristics. For example based on ecological study of two reservoirs in the Midwest, Turnage et al. 2013 conclude that weed invasions are more likely in clearer lakes, ones that are closer to infested lakes and those that have high motorboat activity. MacPherson et al. (2006) uses a dynamic principal-agent model to show that optimal AIP management strategies should account for the different levels of interaction between humans and their environment for example those faced by boaters and managers with AIP. The Minnehaha Creek Watershed District has a comprehensive AIS program including AIP like Milfoil and Curly-Leaf Pondweed and perform AIS management using a systematic approach spanning research, inspection, control and restoration.

While overall these studies suggest AIP lead to substantial economic damages and that they should be controlled, it is not the case that permanent/total control is always the most cost- effective solution. For example, Kirk and Henderson (2000) report the findings of a study in South Carolina that evaluating the economic value of aquatic vegetation for fisheries by combining angler creel surveys and economic models of angler expenditures. They find that a balanced amount of plant control gives the highest economic value while a small amount of plant control (59% plants remaining) gives the highest economic impact with values accruing to both anglers and non-anglers. Doing nothing to control weeds actually gives a higher economic impact than eradicating all weeds because controlling aquatic vegetation hurts recreational

fishing by decreasing boat-angler use. Also, Frid et al. (2009) estimate the economic impact of AIP in British Columbia lakes to find that given inventory and treatment budgets, net present value (NPV) of controlling AIP using a mechanical treatment program, was positive but NPV could be negative if inventory budget was low or treatment budget was high. They propose an integrated economic valuation framework for invasive weeds taking into account ecological carrying capacity, invasion risk, damages and extent of current coverage. Their approach is illustrated in figure 2.

Conclusions Overall from the papers examined so far, we find that AIS have net negative economic impacts but only a few studies have been conducted to explicitly estimate these impacts in the Upper Midwest region (20 studies out of 108: 18%). Apart from this, economic impact figures seem to differ from year to year, with the kind of species controlled, with the method used and even with the study area for the same species. More studies on AIS and specifically on species in the Upper Midwest and Great Lakes region are needed to estimate the economic impact of these species more objectively and suggest a suite of effective management strategies. The most cited control methods for AIS reviewed were chemical treatment and physical harvest. As management costs are substantial, one key question facing decision-makers is the relative importance of prevention and control as a management strategy and the corresponding allocation of public funds. According to Keller et al. (2008), prevention is the best method to reduce ecological impacts of AIS as these can be complex and be prevalent even after management actions are undertaken. From their Targeted management, accounting for invasion risk for Rusty Crayfish was found to generate net economic benefits of $6 million for Vilas county lakes in Wisconsin for a 30 year period (1975-2005). Second, by a cost comparison, it is prevention that seems to win. For example, the Office of Technology Assessment (OTA 1993) reports that the cost of managing existing AIS in the US is 16:1 times higher than the cost of prevention. Also Wick, 2013 reports that over the last 26 years (1986-2012), it has cost the Lake George community an estimated $6.5 million to combat EWM, Zebra Mussels and Asian clams. Also Table 1-3, “Economic Returns on AIS Management,” on page 1-10 shows that prevention measures at the “entry stage” for AIS is a better investment compared to control strategies after AIS are established, given data for Lake George. Also as Gozlan et al (2008) reminds us, not all

invasive species “are bad’. For example, among the 132 freshwater fishes in the FAO database, 103 were reported to be introduced and more than half of these (52%) do not have any reported ecological impact on the native ecosystem. Additionally, the risk of ecological impact after the introduction of a freshwater fish species is less than 10% for the great majority of fish species introduced (84%) (Gozlan et al 2008). However invasion risk is variable across families of invasive fishes depending upon ecological characteristics as shown by Kolar and Lodge (2002), for the Great Lakes region. This highlights the distinctions between non-native or exotic species and those that become nuisance or invasive species. This suggests that for policy measures to be cost-effective, they need to prioritize and target those species that have the highest net ecological and economic impacts. To do this, invasive species policies need to be more in sync with the current scientific literature on invasive species.

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Part 2: Expenditures on Treatment and Control

Introduction to Part 2 The second part of the project on ‘Economic aspects of aquatic invasive species’, is concerned with how much states spend on AIS control and prevention in the Upper Midwest region. We looked for the following types of data: AIS management measures such as herbicide application (control) and watercraft inspection (prevention) by AIS type, waterbody name, inspection agency, type of treatment, coverage in terms of acres treated/boats inspected, and dollars spent. Using these data, we present a distribution of expenditures per acre for each species if known. The results presented in our report and any inferences drawn from them are dependent on data quality and availability. Therefore we note that our analysis of AIS expenditures reflects data from public and private organizations. It does not address the added costs to private individuals nor public infrastructure; such as: increased costs in maintenance and repair for boats, docks, and lift equipment; increased maintenance and replacement costs for pipes to use lakewater (e.g., for watering lawns, etc.); the value of people’s time to perform maintenance, transport equipment for repairs, etc.; and finally, costs for public infrastructure, for example increased need to clean/maintain pipe outlets, increased need to maintain public launches and public beaches (and attendant disposal costs). Here we summarize results for AIS management and expenditure data for the Great Lakes states (including Iowa) and Florida. Florida was included as a model of AIS treatment and data provision while Iowa was included owing to its similarity and proximity to the Great Lakes states. To compile these data, we looked at the websites of the state DNRs and also contacted key AIS experts in these agencies. The response was not uniform and ranged between no data (Michigan, Ohio, and Pennsylvania), to high quality well aggregated data (Florida). Only two states provided us with both treatment and inspection data: Minnesota and Wisconsin. Florida, Indiana, and New York only provided treatment data. In the following paragraphs we present summaries of available data obtained from four Great Lakes states: Indiana, Minnesota, New York, and Wisconsin, and Florida; followed by concluding remarks for this report and final recommendations for MCWD. We start with an expenditure summary in Table 1 where average AIS expenditure per year by type is shown for these five states, for years in which data are available. All figures in Table 1 are in terms of 2013 dollars.

Table 1: AIS Expenditure Summary: Average spending for Five States (adjusted to 2013$s) Wisconsin Indiana Minnesota New York Florida (fees, 2008- (2012-13) (2006-13) (2005-07) (2009-13) 13) Treatment $1,425,615 $10,922,488 $3,266,381 $483,189 98,432,104 Inspection $16,519,392 Average $712,808 $3,430,235 $1,633,190 $96,638 19,686,421 spending

Indiana Data Description: Data on treatment and spending was obtained for 2012-2013 from the Indiana DNR: http://www.in.gov/dnr/ In total, the state of Indiana, the Great Lakes Restoration Initiative (federal initiative), and the Lake and River Enhancement (local body) spent $1,416,213 over 2012-2013 on AIS treatment activities in lakes both inside and outside the Great Lakes basin of Indiana. This translates to a total spending of $1,425,615 and an average spending of $712,808 over 2012-2013, when converted to 2013 dollars, as shown in Table 1. After considering total acres treated, the treatment cost per acre in 2013 dollars is $376, as shown in Table 5. All of the AIS species treated in Indiana are aquatic invasive plants: Eurasian watermilfoil (EWM), Curly-leaf Pondweed (CLP), Hydrilla, and Starry Stonewort. Herbicides were the main treatment method used as the summary table, Table 2 shows. Two types of cost per acre numbers can be reported: (i). Average total dollars per acre, which is simply total dollars spent, divided by total acres treated during the relevant period (here 2012- 2013); and (ii). Average dollars per acre by species/waterbody/county, which is sum of total dollars per acre for 2012-2013, divided by total number of species/waterbodies/counties treated. The first number reports average total costs per acre across all units (species, waterbodies, or counties) treated, while the second number captures variations in cost per acre for different units. For Indiana, there were in total, 28 waterbodies that had both spending and acreage figures so we can report (i). the average total dollars per acre number across 28 waterbodies for 2012-2013, which was $332 ($376 in 2013 dollars); and (ii). the average dollars per acre number by

waterbody, which was $434, due to variation across waterbodies in terms of acreage, treatment methods and associated costs (see Figure 1).

Table 2: Spending by AIS species and Treatment Type for Indiana, 2012-2013

Starry AIS species CLP EWM EWM, CLP Hydrilla Grand Total Stonewort Weevils 44,125 44,125

2,4-D 255,116 255,116

2,4-D, Aquathol K 179,877 179,877

2,4-D, Triclopyr 12,554 12,554

2,4-D, Triclopyr, 14,202 14,202 Aquathol K

Aquathol K 7,431 7,431

Diquat 7,614 41,170 48,784

Triclopyr 17,088 17,088

Cutrine 266,875 266,875 Ultra/hydrothol 191

2,4-D Navigate 2,876 2,876

Flouridone 567,286 567,286

Grand Total 7,431 339,372 235,249 567,286 266,875 1,416,213

Figure 1 : Treatment Costs per Acre by Waterbody in Indiana for 2012-2013

Worster West Otter Lake Lake Wawasee Wall Lake Tippecanoe Syracuse Lake Sylvan Lake Stone and Brokesha… Pretty Lake Oliver, Olin, and… Little Turkey Lake Pleasant Lake Manitou Jimmerson Lake Hamilton Lake Lake Goldeneye Lake George Failing Lake Dewart Lake Crooked Lake Big Turkey and Henry… Big Long Lake Atwood Lake Adams Lake 0 200 400 600 800 1,000 Dollars per Acre

Source: The data used in Table 2 and Figure 1, were obtained from the Indiana Department of Natural Resources. These data and the relevant analyses are found here: ..\Data\Great Lakes\Indiana\Invasive control efforts Indiana 2012-2013 for Minn-modified.xlsx

Minnesota Data Description: The distribution of Aquatic Invasive Species in Minnesota is shown by this map, recently released by the Minnesota DNR: http://minnesota.publicradio.org/projects/2014/04/invasive-aquatic-species-map/. The map was constructed by merging the variables ‘Year designated’ and ‘Year confirmed’ in the invasive species GIS database maintained by the DNR, called ‘Infested Waters’ (5). This simplified the analyses but might have resulted in slight differences between this map and actual concentrations. Data on AIS management and prevention expenditures for Minnesota was collected from several different sources. Data on AIS management and spending by local government agencies

and other organizations like private groups and individuals was obtained from Minnesota Coalition of Lake Associations (MN COLA). Based on MN COLA’s list, multiple agencies including Minnehaha Creek Watershed District, MN COLA itself, Lake Improvement Districts, and various county governments, spent at least $5,269,622 over 2010-2012 on AIS control and prevention activities18. This expenditure by spending entity (government body, private groups, businesses or individuals), by county, and by type of activity (34 activities listed) is shown in Figures 2a. and 2b. These spending activities clearly have a positive trend over the three year period. We also note that about 40% of the total spending occurred in 2012 and that homeowners as a group contributed substantially: 32% to the total spending of $5.3 million. Aggregate expenditure on management as well as prevention was gathered from publicly available Minnesota DNR annual reports on invasive species. These data are summarized by AIS spending category for eight years in Figure 3. Treatment data on a single AIP over a 23 year period, purple loosestrife, was obtained from the 2012 DNR annual report. This is shown by Figure 4. Finally, treatment data for 2012-2013 on specific AIPs deemed particularly invasive by the Minnesota DNR and funded by DNR grants as well as regional and local entities were obtained from the Invasive Species Control Grant database of the Minnesota DNR. These data are detailed by county, waterbody, treatment, acres and total costs, and are summarized in Figures 5 and 6. In addition, the Minnesota DNR maintains a special database called the Outcomes Tracking System for storing grants data. A portion of the data on invasive species grants is currently in this database. Currently there are invasive species grants from 2008-2014, amounting to about $1.9 million, from which a map of grant allocation by county was generated. This map, labelled Figure 12, is provided at the end of this section. For simplicity and ease of comparison, Table 1 shows total spending and average spending per year on AIS activities by the Minnesota DNR over 2006-2013. These figures, in terms of 2013 dollars, are $27,441,880 and $3,430,235 respectively. Detailed treatment data, including treated acres, is available only for 2012 and 2013. The average treatment cost per acre for these years was $305. Figure 3 shows, in aggregate, annual treatment spending and inspection

18 The list of expenditures compiled by MN COLA is not complete and exhaustive, but rather an attempt through voluntary reporting and research to gain some information about the extent of expenditures to manage AIS.

spending. Both types of spending show a positive trend through the years but the rate of increase for inspection spending is clearly higher than that for treatment spending, indicating the importance of prevention measures for the future. Treatment spending using chemicals, for a specific AIP species, Purple Loosestrife, is shown by Figure 4. As Purple Loosestrife is quite resilient, and since herbicide application only kills the existing population in a treated area, chemical treatment has been supplemented by biological control using insects (two species of leaf-eating beetles, one species of root-boring weevil and one species of flower-feeding weevil) since 1992. A 2012 DNR assessment found that leaf- eating beetles have increased in abundance and have caused damage to 11% of 61 Purple Loosestrife sites that were surveyed. This effort has kept Purple Loosestrife populations under control in Minnesota and is expected to reduce its abundance in Minnesota wetlands in the future.19 Though Figure 4 shows a declining trend in chemical treatment due to this reason, herbicide applications on a small number of Purple Loosestrife infestations each year help prevent the spread of this plant into uninfested wetlands and lakeshores. Spending data for 2013 is not yet available although a small number of sites (29) were treated in 2013. Using biological control by insects is a natural method compared to chemical treatment but requires production, rearing, waiting for populations to establish, and finally release and transfer (as needed) of insects near or between infested sites. The costs involved are unavailable from the DNR reports, but if these are lower or comparable to chemical treatment costs, biological control could be a more sustainable and less invasive method of monitoring AIP like Purple Loosestrife. Detailed data on AIP treatment by the DNR was obtained from the DNR’s Control Grant database for the period 2012-2013. Figures 5 and 6, based on these data, show per acre costs for treating specific AIPs--Milfoil, Curly-Leaf Pondweed, and Flowering Rush--by species and by county in 2012-2013. The most common treatment method used was chemical treatment with popular herbicides like 2, 4-D or Aquathol-K. As Figure 5 shows, treatment costs were below $400 for all AIP treated during the period except the combination Milfoil and Flowering Rush, which was very high owing to only two acres being treated. Only 40 counties had both spending and acreage information for which per acre costs could be derived. As Figure 6 shows, per acre treatment

19 MN DNR 2012 Annual Report: ..\Data\Great Lakes\Minnesota\Annual Reports\2012_invasive_species_annual_report_final.pdf 43

costs for most counties was below $400 except for a few counties like Blue Earth and St. Louis which went beyond $800 per acre. The average total cost per acre across counties was $304 while for across species it was $305. The average cost per acre by county was $378 while by species, it was $448. Data on watercraft inspections was collected from DNR annual reports. 565,600 boats were inspected over 2006-2013 amounting to a total inspection time of 349,600 hours and a total cost of $16,519,392 in 2013 dollars as Table 1 shows. The average dollars spent per boat was $28 over 2006-2013, i.e. $29 in 2013 dollars. The inspection time spent per boat was 36 minutes. Figure 7 summarizes the inspection data indicating a steady increase in both spending and number of boats inspected over 2006-2013, while Figure 8 shows the inflation unadjusted dollars spent per boat over the same period, also with an upward trend. The latter is explained by the rate of increase in inspection spending being higher than the rate of increase in the number of boats inspected (see Figure 7).

Figures 2a: AIS spending by Local Government Agencies reported by the Minnesota Coalition of Lake Associations (MN COLA), 2010-2012 (not inflation adjusted) Sum of How much money did they spend on that item? Column Labels Row Labels 2010 2011 2012 Grand Total City or township government 22,500 62,000 107,500 192,000 COLA or LARA 3,284 14,784 13,250 31,318 County government 2,000 5,000 44,300 51,300 Homeowners (as a group) 567,800 551,590 544,000 1,663,390 Individual 2,000 2,000 Lake Improvement District (LID) 285,231 207,990 267,107 760,328 Lake, river, or creek association 366,663 482,051 717,672 1,566,386 Other: Community fundraising 30,000 20,000 10,000 60,000 Other: Initiative Foundation 5,000 5,000 Other: Minnesota Power 5,000 5,000 Other: Private land foundation grant 5,000 5,000 Park District 6,900 10,000 10,000 26,900 Watershed District 187,500 327,500 382,500 897,500 Businesses 1,500 2,000 3,500 Grand Total 1,478,878 1,682,415 2,108,329 5,269,622 Sum of How much money did Column they spend on that item? Labels Grand Row Labels 2010 2011 2012 Total Becker 195,000 309,000 261,500 765,500 Cass 4,784 7,673 24,389 36,846 CMCW 798,778 843,678 1,111,153 2,753,609 Crow Wing 269,289 285,278 245,276 799,843 Hubbard 34,500 22,250 122,000 178,750 Itasca 5,250 5,750 17,750 28,750 Kandiyohi 1,500 5,000 8,000 14,500 Meeker 15,500 32,000 38,000 85,500 Otter Tail 2,692 11,912 18,621 33,225 PICKM 25,000 30,500 86,500 142,000 Stearns 16,835 20,624 20,890 58,349 Wright 109,750 108,750 154,250 372,750 Grand Total 1,478,878 1,682,415 2,108,329 5,269,622

Figure 2b: AIS spending by type compiled by the Minnesota Coalition of Lake Associations (MN COLA), 2010-2012 (not inflation adjusted) Row Labels Total AIS Bag distribution 2,000 AIS education and/or awareness 97,852 AIS monitoring & other projects 200,000 AIS Vegetation Survey 4,000 AIS Vegetation Surveys 8,000 AIS-related volunteer activities 4,000 AIS-related volunteer hours 500 Carp removal 5,500 Chemical treatments of AIS plants 2,992,006 Curly-leaf Pondweed/ Flowering Rush Roadside pickup 140,000 Decontamination equipment 17,000 Decontamination services 50,000 Electronic gate for Christmas Lake 27,000 Equipment Maintenance 3,000 Flowering Rush Research 350,000 Hand harvesting of AIS plants 210,250 I-LIDS 52,500 Improvements to public accesses 100 Improvements to public accesses related to AIS (weed dumpsters, drain areas, etc.) 1,000 Inspection services using DNR certified inspectors 384,639 Inspection services using paid "volunteers" (at actual costs or $10/hr if unknown) 126,456 Inspection (paid "volunteers" or $10/hr) 5,017 Inspection (unpaid volunteers at $10/hr) 45,808 Investigation into AIS issue 600 Lake Monitoring for AIS 1,500 Mechanical harvesting of AIS plants 413,500 Motion-activated video inspection equipment and operation (I-LIDS) 15,000 P.I.S at public watercraft accesses 3,000 Project management volunteer hours 8,000 Signs 400 Training, books, uniforms, plant survey, GPS 2,994 Various AIS volunteer hours 1,500 Weevil control of EWM 20,000 Beach FR Clean-up 76,500 Grand Total 5,269,622

Source: The data, analyses and charts shown here are from MN COLA and can be found here: ..\Data\MNCOLA data\April 29, 2013 data - BACKUP DATASET\April 29, 2013 data - BACKUP DATASET\MN COLA Consolidated Spending on AIS v4.0.xlsx

Figure 3 : AIS Spending by Minnesota DNR, by category for 2006-2013 (not inflation adjusted) $7,000,000

$6,000,000

$5,000,000

$4,000,000

$3,000,000 Inspection $2,000,000

Spending in US US Dollarsin Spending $1,000,000 Treatment $0 2006 2007 2008 2009 2010 2011 2012 2013 Year

Figure 4: Expenditure on Chemical Control of Purple Loosestrife by Minnesota DNR (not inflation adjusted) 120,000

100,000

80,000

60,000

40,000

20,000 Spending in US dollarsSpending

- 1988 1992 1996 2000 2004 2008 2012 Year

Source: The data used in Figures 3 and 4 is obtained from Minnesota DNR annual reports on AIS management, which can be found here: ..\Data\Great Lakes\Minnesota\Annual Reports The analysis and charts presented here are found here: ..\Data\Great Lakes\Minnesota\MN-AIS-data- 1.xlsx

Figure 5: Treatment Costs per Acre by Species for Milfoil, Curly-Leaf Pondweed, and Flowering Rush, in Minnesota, 2012-2013

Flowering Rush

Milfoil and Flowering Rush

Milfoil

Curly-leaf pondweed and Flowering Rush

Curly-leaf pondweed

Curly-leaf pondweed and Milfoil

0 300 600 900 1,200 1,500 Dollars per Acre

Figure 6 : AIS Treatment Costs per Acre by County in Minnesota, 2012-2013

Yellow Medicine Wright Washington Waseca Wadena Todd Stearns St. Louis Sherburne Scott Rice Ramsey Pope Polk Pine Ottertail Morrison Meeker McLeod Lincoln LeSueur Kandiyohi Kanabec Itasca Isanti Hubbard Hennepin Douglas Dakota Crow Wing Cottonwood Chisago Cass Carver Carlton Brown Blue Earth Becker Anoka Aitkin 0 200 400 600 800 1000 1200 1400 Dollars per Acre

Source: The data and analyses used in Figures 5 and 6 can be found here: ..\Data\Great Lakes\Minnesota\Wendy Crowell Control Grant Data\2012 - 2013 AIS Control Grant data.xlsx

Figure 7 : Annual Watercraft Inspections Spending and Boats Inspected by Minnesota DNR

$7,000,000 140,000

$6,000,000 120,000

$5,000,000 100,000 Number of Boats $4,000,000 80,000

$3,000,000 60,000

$2,000,000 40,000 Number of Boatsof Number Inspection Spending Inspection Spending in $s Spending Inspection $1,000,000 20,000

$0 0 2006 2007 2008 2009 2010 2011 2012 2013 Year

Figure 8: Inspection Spending per Boat for Boats inspected by Minnesota DNR

Dollars per Boat per Dollars 10

0 2006 2007 2008 2009 2010 2011 2012 2013 Year

Source: The data and analyses for Figures 7 and 8 can be found here: ..\Data\Great Lakes\Minnesota\MN-AIS-data-1.xlsx DNR annual reports can be found here: ..\Data\Great Lakes\Minnesota\Annual Reports

Figure 9: Total Allocation for DNR Invasive Species Grants, 2008-2014 (not inflation adjusted)

Source: Compiled by authors from DNR Grants data as of May 15, 2014.

New York Data Description: Data on AIS treatment for 2006-2007 was obtained from the New York Department of Environmental Conservation. More data on selected AIS species were obtained from a few local government agencies. Total spending over 2006-2007 in 2013 dollars, was $3,266,381 and average spending per year was $1,633,190, as shown in Table 1. The corresponding cost per acre is reported in Table 5. In total 9,094 acres of AIS species were treated by the NY Department of Environmental Conservation over 2006-2007. About 80% of these acres were treated in 2006 for a total treatment spending of $1,079,757. For this reason, we focus on the year 2006 in the tables and charts presented in this section. Table 3 summarizes these 2006 data by different AIS species treated and the corresponding treatment methods. In total about 11 different types of AIS including invasive plants and animals were treated in 2006, although plants seem to dominate. Among treatment methods used, physical (36%) and chemical (26%) treatments comprise a large share of total treatment expenditure. Figure 10 shows treatment cost per acre for eight AIS for which acreage information was available. One species-European Frog’s bit, was dropped owing to being an outlier. Figure 11 shows the distribution of the 2006 treatment spending per acre across over 30 project sites, mainly waterbodies like lakes and rivers. There was high variation in cost per acre for treatment due to difference in acres treated and methods used for each waterbody. Cost per acre for 2006 was $148 while for 2007; it was $992 giving an average cost per acre of $570 over this period. As the available data for NY is in clusters that are not mutually exclusive (as Table 3 shows), it is not amenable to producing an accurate estimate of average cost per acre by AIS species at this time. We also obtained information on management of three more AIS in New York: Hydrilla management in the Cayuga Inlet from James Balyszak; management of Snakehead fish in Orange County from Michael Flaherty, and Zebra Mussel management in Lake George from Dave Wick of the Lake George Conservation Commission. We also obtained more data on Milfoil management in Lake George, from Dave Wick. According to Michael Flaherty of the New York Department of Environmental Conservation, more than 77 acres in three waterbodies (2 mile stretch of Catlin Creek, Ridgebury Lake and a 49 acre wetland) in the town of Wawayanda, Orange County, New York, were treated with the piscicide Rotenone in August

2008 and October 2009 for Snakehead fish and the total dollars spent were over $300,000. For Zebra Mussel management in Lake George about 7,331 inspection hours were spent between1999-2010 at a total cost of $335,168. Data for Hydrilla management is summarized in Figure 12. Data for Milfoil Management in Lake George is summarized by Figure 13. According to Mr. Wick, in Lake George, Milfoil control has never been conducted through chemical applications, but rather through hand harvesting and benthic matting. The state of New York is starting a new mandatory watercraft inspection program from this year.

Table 3: Treatment type and spending by AIS species in New York, 2006 Grand AIS Species Biological Chemical Combo Mechanical Physical Total Asian shore crab 35,000 35,000 Blue-green algae, coontail & EWM 28,000 28,000 CLP 4,699 4,699 European Frog's-bit 27,330 27,330 EWM 104,710 156,565 31,865 406,948 700,087 EWM & CLP 68,790 66,987 28,833 164,610 EWM & other AIP 5,000 5,000 EWM & Water Chestnut 90,000 90,000 EWM, IL pondweed & CLP 16,226 16,226 General AIS 100,000 100,000 IL pondweed 12,615 12,615 Phragmites 60,000 104,434 15,121 179,555 Phragmites & Japanese Knotweed 13,155 13,155 Phragmites, PL & Water Chestnut 15,437 15,437 PL 10,000 10,000 PL & Phragmites 50,000 50,000 Water Chestnut 16,063 10,871 59,954 Water Primrose 26,046 26,046 Water Chestnut, Phragmites & PL 10,000 10,000 Grand Total 114,710 409,434 375,536 64,865 550,149 1,547,714 Note for Table 3: CLP=Curly Leaf Pondweed, EWM=Eurasian watermilfoil, IL Pondweed=Illinois Pondweed, PL=Purple Loosestrife

Figure 10: Treatment Costs per Acre by AIS species in New York, 2006 (not inflation adjusted)

Water Chestnut Purple Loosestrife and Phragmites Purple Loosestrife Phragmites, Purple Loosestrife and… Phragmites and Japanese Knotweed Phragmites EWM, Illinois pondweed and CLP EWM and Water chestnut EWM and other AIP EWM and CLP EWM CLP Asian shore crab 0 20,000 40,000 60,000 80,000 100,000 120,000

Dollars per Acre

Figure 11: Treatment Costs per Acre by Waterbody for New York, 2006 (not inflation adjusted)

Waneta Upper Sarana Town Commons Tibet Tarrytown Upper Lake South Shore estaury reserve Second Creek, Sodus Bay Schroon Saratoga Reservoir #3 Owasco Oscawana Island Oneida, Seneca Rivers Mountain View Loon Lake Casse, Upper and Lower Teakettle spout… Glen, Warren George Fort pond Five Bornx Parks Eagle Crossway Fields & Harwood Park wetlands Cossayuna Collins Colby, Franklin Chautauqua Brandt Bonaparte 5th, 6th and 7th lakes 4 Audubon sanctuaries 0 4,000 8,000 12,000 16,000

Dollars per Acre

Source: The data used for Table 3 and Figures 10-11 can be found here: ..\Data\Great Lakes\New York\Treatment data\NYtreatment-data1.xlsx

Figure 12: Treatment Costs per Acre for Hydrilla in Cayuga Inlet, New York, 2011-2013

3,500

3,000

2,500

2,000

1,500

1,000 Dollars per Acre per Dollars 500

0 2011 2012 2013 Year Source: The data and analysis for Figure 12 can be found here: ..\Data\Great Lakes\New York\Treatment data\Cayuga Inlet Hydrilla Project_Funding Breakdown.xlsx

Figure 13: Treatment Costs for Milfoil in Lake George, New York, 1995-2012 $ 400,000

$ 350,000

$ 300,000

$ 250,000

$ 200,000

$ 150,000

Spending in $s in Spending $ 100,000

$ 50,000

$ 0 1995 1997 1999 2001 2003 2005 2007 2009 2011 Year

Source: The data and analysis for Figure 13 can be found here: ..\Data\Great Lakes\New York\Treatment data\Milfoil funding 1995-2012.xls

Wisconsin Data Description: Detailed data on treatment without expenditure information was received from the Wisconsin DNR. According to agency personnel, the years 2008, 2009, 2010, 2011, and 2013 have the most complete data. Treatment spending and average spending in terms of fees for the period 2008-2013, excluding 2012 was $483,189 and $96,638, respectively as shown in Table 1 in 2013 dollars. The corresponding cost per acre was just $21 as shown in Table 5. Table 4 summarizes the types of AIP (about 11 types) treated in different waterbodies in Wisconsin during this time period. Also included is the total treatment fees paid, which is a part of the total treatment costs (unavailable). Watercraft inspection information excluding inspection costs was also received from the Wisconsin DNR. Figures 14a and 14b show inspection costs per boat for all boats inspected by county during 2008-2013, for 71 counties for which inspection information was available: Figure 14a shows these data for counties starting with letters A through L and Figure 14b shows these data for the rest of the counties. Based on both samples, on average, 34.2 minutes were spent inspecting one boat in Wisconsin over 2008-2013.

Table 4 : Number of AIP treated in different types of waterbodies from 2008-2013 in Wisconsin AIP species by waterbody type Curly Large Leaf Leaf Purple Sago Water Alg Coon Pond Duck Elo Milf Pond Phrag Pithop Looses Pond body ae tail weed weed dea oil weed mites hora trife weed Creek 0 0 0 0 0 0 0 0 0 10 0 Great Lake 21 34 61 28 28 66 35 51 17 1 0 Lake 129 104 286 234 100 424 464 34 27 31 79 Other 1 0 0 0 0 0 0 0 0 0 0 Pond 6 1 1 0 0 0 2 0 0 0 0 River 5 6 19 4 7 25 22 4 0 1 1 Strea m 0 0 0 0 0 0 0 0 0 0 1 Wetla nd 0 0 0 0 0 0 0 1 0 1 3 Grand Total 162 145 367 266 135 515 523 90 44 44 84

Source: The data and analyses for Tables 4 can be found here: ..\Data\Great Lakes\Wisconsin\Treatment and Inspection Data\MoreCompleteWI-APM.xlsx

Figure 14a: Watercraft Inspections Hours per Boat, by County, (A to L), 2005-2014, Wisconsin

Lincoln Langlade Lafayette La Crosse Kewaunee Kenosha Juneau Jefferson Jackson Iron Iowa Green Lake Green Grant Forest Fond du… Florence Eau Claire Dunn Douglas Door Dodge Dane Crawford Columbia Clark Chippewa Calumet Burnett Buffalo Brown Bayfield Barron Ashland Adams 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 Hours per Boat

Figure 14b: Watercraft Inspections Hours per Boat, by County, (M-W), 2005-2014, Wisconsin

Source: The data and analysis used in Figures 14a and 14b can be found here: ..\Data\Great Lakes\Wisconsin\Treatment and Inspection Data\cbcwdata-2014-04-02\cbcwdata-2014-04-02- mod.xlsx

Florida Data Description: Detailed data on expenditure on aquatic invasive plant management for 2009- 2013 was obtained from the Florida Fish and Wildlife Conservation Commission- http://myfwc.com/wildlifehabitats/invasive-plants/ As Table 1 shows, Florida spent $98,432,104 in AIS treatment over 2009-2013, i.e. an average spending of $19,686,421, higher than any of the other states. These results are based on spending figures drawn from Annual Reports for 2009-2013. Figure 15 below shows treatment spending and dollars per acre for 2009-2013 for Florida. Unlike the figures in Table 1 above, these have not been adjusted for inflation. The expenditure and acres figures are from Annual Reports and include both state and federal spending. To corroborate this aggregate figure, we did more detailed analyses on cost per acre for the most recent year with available data, i.e. 2013. We looked at treatment costs per acre by AIS species as well as by county. The results are summarized in Figures 16a and 16b. In total, ‘cost per acre’ numbers are available for 53 species of aquatic invasive plants (AIP) treated in Florida in 52 counties. For Florida in 2013, the total dollars per acre across 53 species, was $236 while the average dollars per acre by species was much higher: $1,438, due to very large cost figures for certain species like the Chinese Tallow Tree, Cyanobacteria and Filamentous Algae, as Figure 16a shows. As expected, the total dollars per acre for 2013 matches the dollars per acre number for 2013 in Figure 15. As Figure 16b shows, the county-specific numbers were less affected by outliers. The average total dollars per acre across 52 counties was $236 (also matches the 2013 dollars per acre number in Figure 15) while the average dollars per acre by county was $269.

Figure 15 : Annual Treatment spending and dollars per acre for Florida (not inflation adjusted)

25,100,000 400 Annual Spending 350

20,100,000 300

15,100,000 250 Annual dollars per acre 200

10,100,000 150

100 Dollars per Acre per Dollars

Spending in US dollars US in Spending 5,100,000 50

100,000 0 2009 2010 2011 2012 2013 Year

Source: The data used is obtained from five annual reports found here: http://myfwc.com/wildlifehabitats/invasive-plants/The chart is found here: ..\Data\Other States\Florida\Treatment Data\Florida-treatment-spending.xlsx

Figure 16a: AIP Treatment Costs by species for Florida, 2013

Yellow Waterlily Yellow pond-lily Willow Waterlily Water Velvet Water Snowflake Water Paspalum Water Hyssop Vallisneria americana Tussocks Tumble Pigweed Tropical American Watergrass Trompetilla Torpedograss Taro Southern Waternymph South American Water Primrose Salvinia Pickerel Weed Phyllanthus Fluitans Phragmites Peruvian Water Primrose Para Grass Panicgrass Nitella Ludwigia leptocarpa Loose/Cutleaf Watermilfoil Limnophila sessiliflora Leafy Bladderwort Japanese Climbing Fern Japanese Bloodgrass Indian Waterweed Illinois Pondweed Hydrilla Giant Salvinia Floating Filamentous algae Dwarf Papyrus Dollarweed Cyanobacteria Cupscale-grass Coontail Climbing Fern Chinese Tallow tree Cattail Carolina Fanwort Bulrush Buckwheat Broad-leaved paperbark Brazilian Waterweed Brazilian Pepper American Spongeplant Alligator Weed 0 5,000 10,000 15,000 20,000 Dollars per acre

Figure 16b: AIP Treatment Costs per Acre by County for Florida, 2013

WALTON WAKULLA VOLUSIA UNION SUWANNEE SUMTER SEMINOLE SARASOTA SAINT LUCIE SAINT JOHNS PUTNAM POLK PINELLAS PASCO PALM BEACH OSCEOLA ORANGE OKEECHOBEE OKALOOSA MIAMI-DADE MARTIN MARION MANATEE MADISON LEON LAKE JEFFERSON JACKSON INDIAN RIVER HOLMES HILLSBOROUGH HIGHLANDS HERNANDO HARDEE HAMILTON GADSDEN FRANKLIN FLAGLER ESCAMBIA DUVAL DIXIE COLUMBIA COLLIER CLAY CITRUS CHARLOTTE BROWARD BREVARD BRADFORD BAY BAKER ALACHUA 0 200 400 600 800 1,000 1,200 Dollars per Acre

Source: The data used for figures 16a and 16b is sourced from the 2013 Florida Aquatic Plant Management report found here: ..\Data\Other States\Florida\Annual reports and documents\AquaticPlantManage_12-13.pdf The analysis and charts are found here: ..\Data\Other States\Florida\Treatment Data\Florida- treatment data by species.xlsx

Comparison of all states Aquatic invasive plants were the main AIS treated by all states. However, the type of plants treated varied across states with Wisconsin treatment being the most diverse. Some states like Florida and New York focused on Hydrilla as a major AIP. All states seem to favor chemical treatments over other treatments, perhaps because herbicides are relatively inexpensive, less labor-intensive and work quickly in the short term. Only New York had data on treatment of AIS apart from plants, as they reported expenditures on Snakehead fish and Zebra Mussel control. Florida had the highest total and average AIS spending, followed by Minnesota, New York, and Indiana, as Table 1 shows. In the following paragraphs we analyze this total spending in terms of its components and in terms of dollars per acre spent on each category.

Treatment: The results on total spending, acres treated, and cost per acre, is shown for all years data is available, and for all AIS treated, for each state. For Indiana and Minnesota, the results are based on 2012-2013, for New York they are based on 2005-2007; for Wisconsin, on the years 2008-2013; and finally for Florida, on the year 2013. The final cost per acre figures for any years before 2013 were converted to 2013 dollars to account for inflation. From Table 5, the cost per acre for treatment (across all AIS treated within a state for a given time period), varied across the five states with Florida having the lowest cost per acre ($289), and Indiana having the largest ($376). Among these states, Wisconsin did not record actual treatment costs but only fees for DNR personnel supervising treatments. As these fees were quite nominal, the per acre cost of $21 over five years is not surprising. In terms of spending as well as acres treated, Florida dominates all the other states. All four states that recorded treatment spending data have cost per acre figures in the range $289-$376, with Minnesota and Florida’s program having the lowest cost per acre. Cost per acre for Indiana is the highest of all five states suggesting a lack of economies of scale since they have treated the lowest number of acres. For New York, the results in Table 1 and Table 5 are based on both 2006 and 2007, although about 38% of spending and 80% of treatment happened in 2006.

Inspection: As regards inspection, it is a comparatively new venture for most states. As prevention seems to be important, inspection promises to be a valuable measure, reflected in the

rising trend for inspection costs for Minnesota as Figure 8 shows. The average inspection cost per boat over 2006-2013, is $29 in 2013 dollars. Also, an average inspection time per boat of 36 minutes is seen for Minnesota over 8 years (2006-2013). For Wisconsin, the average inspection time is slightly shorter: 34.2 minutes per boat over 10 years (2008-2013). See figures 14a and 14b.

Table 5 : Treatment Cost Per Acre Comparison for 5 States in 2013 dollars Total Costs Acres Treated Cost Per Acre

Indiana (2012-2013) $1,425,615 3,795 $376

Minnesota (2012-2013) $3,459,049 11,350 $305

New York (2006-2007) $3,266,381 9,094 $359

Wisconsin (fees for 2012-2013) $483,189 23,241 $21

Florida (2009-2013) $98,432,104 340,538 $289

Conclusions Here we have presented a summary of our data search for management and prevention costs for AIS. Our results on AIS management and prevention costs for the five states showed that treatment cost per acre was in the range of $289-$376 per year. Inspection costs per boat were $29 and inspection time per boat varied between 34-36 minutes. The data we have been able to collect are not sufficient to make precise policy or management prescriptions for the future. Only a few states have a long history of AIS management and a systematic method of collecting and storing AIS treatment data. With regard to inspection, these data are more sparse as many states are yet to start mandatory inspection programs. The data we have presented should be considered as a snapshot of tracking of AIS treatment results and costs including materials and labor (excepting Wisconsin) and location across the Great Lakes states and Florida.

From a long-run conservation perspective, AIS management seems to be costly as AIS are resilient and keep coming back every year. Herbicide treatment may be quick and inexpensive on a per year basis but hardly permanent as Florida’s long record of Hydrilla management clearly shows. Moreover, repeated herbicide application may be harmful to other species and to whole ecosystems (Hellmann et al. 2008). Therefore, prevention of new AIS and the spread of existing AIS may be more prudent for the future. Inspection costs do have a positive trend as shown by Minnesota’s experience but this is due to several factors: large number of lakes, lake-oriented tourism, feedback loops between popular lakes and infestation levels (Horsch and Lewis, 2009), decontamination costs for different types of boats and AIS species, and finally the lack of effectiveness of treatment over time.

Final Recommendations for Minnehaha Creek Watershed District

We have found very little evidence of a consistent approach to the valuation of public actions designed to deal with aquatic invasive species. As we show in figure 1, such an analysis should include careful assessment of the expenditures associated with the action, the probability of a successful outcome from these measures, comprehensive monitoring of any actions that have been undertaken, and theoretically sound economic valuations of measured outcomes. Such a comprehensive analysis is necessary for fiscally prudent public action with respect to invasive species. But it can also be expensive, probably beyond the capacity of the MCWD’s likely budget allocations.

We suggest, however, that the MCWD could undertake some more limited investigations that could be combined with the efforts of other organizations to jointly approach a desired full economic analysis as laid out above.

1. A complete economic valuation analysis of a specific control action in a relatively limited geographic area, making use of structured surveys such as those employed by economists in many other areas of resource management. The research question would be: Do the economic gains from a control measure, adjusted by probability of success, outweigh the expenditures necessary to carry out that measure? 2. A detail examination of actual private (residential and small commercial) expenditures to limit damages from already-established aquatic invasive species. The research question

would be: How much do people have to spend to deal with invasives, once established? This number, presumably, could then be compared against the cost of actions proposed to prevent the establishment of aquatic invasive species in the first place.

Contact Information

Florida Indiana Minnesota New York Wisconsin Data Treatment Treatment Treatment Treatment Treatment type Inspection Inspection Years 2009-2013 2012-2013 2012-2013 2005-2007 2008-2013 Link to ..\Data\Other ..\Data\Great ..\Data\Great ..\Data\Great Lakes\New ..\Data\Great example States\Florida\Treatment Lakes\Indiana\Invasive Lakes\Minnesota\Wendy York\Treatment Lakes\Wisconsin\Treatment Data\Florida 2013 data.xlsx control efforts Indiana 2012-Crowell Control Grant data\NYtreatment-data1.xlsxand Inspection 2013 for Minn-modified.xlsxData \2012 - 2013 AIS Data\MoreCompleteWI- Control Grant data.xlsx APM.xlsx

Contact Florida Fish and Doug Keller, Wendy Crowell, Leslie Surprenant, Kelsey Brown, Informati Wildlife Indiana DNR Chip Welling, Ann Michael Flaherty, Jennifer Filbert, on Conservation Pierce, Adam Doll, James Balyszak, Wisconsin DNR Commission Minnesota DNR Dave Wick, website NY Dept of Env Conservation; Lake George Conservation Commission Website http://myfwc.com/wildlif http://www.in.gov/dnr/fis http://www.dnr.state.mn. http://www.dec.ny.gov/a http://dnr.wi.gov/lakes/in ehabitats/invasive-plants/ hwild/3628.htm/ us/invasives/eco/index.ht nimals/50121.html vasives/ ml

References for Part 2 Balgie, S., Crowell, W., Enger, S., Johanson, M., Montz, G., Norrgard, R., ... & Wright, D. (2003). Minnesota Department of Natural Resources: Exotic Species Program. Florida Annual reports: ..\Data\Other States\Florida\Annual reports and documents Hellmann, J. J., Byers, J. E., Bierwagen, B. G., & Dukes, J. S. (2008). Five potential consequences of climate change for invasive species. Conservation Biology, 22(3), 534-543. Horsch, E. J., & Lewis, D. J. (2009). The effects of aquatic invasive species on property values: evidence from a quasi-experiment. Land Economics, 85(3), 391-409. Infested Waters List for Minnesota: ..\Data\Great Lakes\Minnesota\Infested Waters\Infested_waters 4-29-13.xls Map of Aquatic Invasive Species in Minnesota: http://minnesota.publicradio.org/projects/2014/04/invasive-aquatic-species-map/ Minnesota Annual Reports: ..\Data\Great Lakes\Minnesota\Annual Reports OSU 2013 conversion chart for 2013: http://oregonstate.edu/cla/polisci/individual-year- conversion-factor-tables