Amphibian Husbandry Resource Guide Edited by: Vicky A. Poole, National Aquarium – Baltimore Shelly Grow, Association of Zoos & Aquariums Edition 2.0, 4 April 2012 For more information about AZA and its amphibian programs, visit http://www.aza.org/ConScience/Amphibians_Intro/ Table of Contents Foreword………………………………………………………………………………………………………………………………..….3 Chapter 1: General Amphibian Husbandry……………………..……………………………………………….….4 Chapter 2: Assisted Reproductive Technologies (ART) for Amphibians………………….60 Chapter 3: Hygiene and Disease Management: Field and Captivity…………………………..119 Chapter 4: Amphibian Quarantine and Isolation Guidelines……………………………………….129 Chapter 5: Creating Isolation Spaces for Amphibian Programs ……...……………..………..143 Chapter 6: Amphibian Population Management Guidelines*…………………………………….200 Chapter 7: Amphibian Data Entry Guidelines **……………………………………………………………232 * This chapter has been previously published. The recommended citation is: Schad, K., (ed.). 2008. Amphibian Population Management Guidelines. Amphibian Ark Amphibian Population Management Workshop; 2007 December 10-11; San Diego, CA, USA. Amphibian Ark. 31 p. ** This chapter has been previously published. The recommended citation is: Schad, K., (ed.). 2010. Amphibian Data Entry Guidelines. Population Management Center, Lincoln Park Zoo. Chicago, IL, USA. 7 p. Acknowledgements: The editors would like to thank the following people for their assistance in editing and reviewing this document: Daniel Beckwith (John G. Shedd Aquarium), Joseph R. Mendelson III, Ph.D. (Zoo Atlanta), Nathanial Nelson (Sedgwick County Zoo), Allan Pessier, D.V.M. (San Diego Zoo – Institute for Conservation Research), and Andrew T. Snider. Recommended citation: Poole, V.A. and S. Grow (eds.). 2012. Amphibian Husbandry Resource Guide, Edition 2.0. Association of Zoos and Aquariums, Silver Spring, MD. pp. 238. Amphibian Husbandry Resource Guide, Edition 2.0 2 A publication of AZA’s Amphibian Taxon Advisory Group, 2012 Foreword The Association of Zoos and Aquarium (AZA) Amphibian Taxon Advisory Group (ATAG) created the first version of the Amphibian Husbandry Resource Guide in response to the global amphibian crisis as a user-friendly source to aid in the development of successful amphibian conservation programs. As the zoological community continues to employ resources and expand amphibian capacity, ex situ management of amphibians remains a crucial component to aid species whose threats in the wild cannot be alleviated in time to halt their extinction. With over 6,900 species of amphibians in the world, there is still much to be learned about their natural history and captive husbandry requirements.1 This lack of information and expertise can impede the urgent action needed for the 500+ threatened species in risk of disappearing within the immediate future. The zoological community and private sector have made great strides within the last two decades regarding amphibian husbandry and reproduction techniques, and we continue to develop new and innovative methods each year. However, as amphibian populations wane, we must quickly and effectively pool our resources, share our expertise, and learn from our experiences to effectively remain ahead of the extinction tide. Hopefully this second edition of the Amphibian Husbandry Resource Guide will not only serve as a resource for amphibian husbandry and management, but will help others solve challenges and create additional space for species in need of immediate conservation. In addition to this resource guide, the ATAG has produced numerous materials over the past few years to help develop successful amphibian conservation and/or research programs (either in situ or ex situ; internationally or domestically). These publications include the Action Plan for Ex Situ Amphibian Conservation in the AZA Community (2007), a detailed description of current amphibian collections and spaces within the AZA community; the Conservation Resource Manual (2007) to aid in the development of successful amphibian conservation programs that fit into institution’s collection plans, which are appropriate for different levels of resources, and provides species specific action plans and husbandry manuals; the ATAG Regional Collection Plan (2008) to guide AZA institutions in collection planning, species management, research and educational outreach; and Taxon Management Plans for North American and Caribbean species that have been identified as priority species for conservation action. The AZA has also published Amphibian Conservation: 2010 Highlights and Accomplishments, which provides excellent examples of in situ and ex situ amphibian programs/techniques which could be applied to new programs in the future. All of these resources can be accessed at: www.aza.org/amphibian-population-planning or www.saveamphibians.org. In addition, the ATAG recommends the AZA Professional Development Committee’s Amphibian Biology, Conservation, and Management course (www.aza.org/prodev/) to improve amphibian husbandry techniques and to benefit from interacting with other amphibian herpetologists, as well as participate in networking opportunities at the annual ATAG meetings. The contributors to the above-mentioned resources are talented individuals who are always willing to share their expertise and dedicate time and resources to the world in which we happily share with amphibians. For their generosity, I thank them. The ATAG is here to help. Please feel free to contact me, Diane Barber, ATAG Chair, at [email protected], or (817) 759-7180 for any question or challenge, large or small. Sincerely, Diane Barber 1 The taxonomy of amphibians is always changing; however, the ATAG uses the taxonomy presented by the Amphibian Species of the World website (http://research.amnh.org/vz/herpetology/amphibia/). Amphibian Husbandry Resource Guide, Edition 2.0 3 A publication of AZA’s Amphibian Taxon Advisory Group, 2012 Chapter 1 General Amphibian Husbandry Jennifer B. Pramuk1 and Ron Gagliardo2 1 Woodland Park Zoo 601 N. 59th Street Seattle, WA 98103 [email protected] 2 Amphibian Ark [email protected] A “red eft” phase eastern newt (Notopthalmus viridescens) (photo courtesy of Brad Wilson, DVM) Introduction Enclosures Water Environmental Conditions Food Natural History and Behavior Veterinary Medicine Literature Cited Additional Recommended Literature Additional Internet and Product Supplier Resources Chapter 1: General Amphibian Husbandry INTRODUCTION There are many reasons to keep amphibians in captivity including for purposes of exhibition, education, conservation, preservation, and for hobby and personal interests. Historically, zoos have included amphibians within their herpetology programs and displays; however, as they become more conservation-oriented (versus the menageries of the past), zoos will have to alter their collections to reflect their resources and capacities to carry out this work (Rabb, 2004). The financial and spatial requirements necessary to meet conservation goals and propagate critically endangered amphibians are significantly less than those required for larger species (e.g., elephants); be prepared to commit sufficient resources and plan properly for long-term success. The Amphibian Ark (www.AmphibanArk.org) has estimated that approximately 500 species of amphibians are in need of carefully managed ex situ help; yet, today likely fewer than 31 species are in managed programs (K. Zippel, pers. comm.). Amphibians comprise a group of vertebrates that display an enormous diversity of natural histories. Within the three orders, anurans (frogs and toads), salamanders, and caecilians, there are more than 6,900 species (www.amphibiaweb.org) with potentially many hundreds more awaiting discovery and description. To give the reader an idea of how many amphibians remain to be described by science, approximately one quarter of all known amphibian diversity has been described in the past 20 years, with the rate of species discovery not yet having reached a plateau. Within the class Amphibia, lifestyles run the gamut from terrestrial to fully aquatic as adults, with some species even adapting and thriving in arid regions of the world. Reproductive modes range from the “typical” amphibian that is terrestrial as an adult but lays aquatic eggs that hatch into aquatic larvae, to species that brood their eggs within their vocal slits or special pouches on their backs, to females that are viviparous (give live birth). Within vertebrates, only fishes rival this wide range of reproductive modes. Because the ecological characteristics and husbandry requirements of amphibians are so diverse, it is impossible to cover specific guidelines for all groups in this document. This short guide provides very basic information on how to maintain captive amphibians. Good husbandry practices can circumvent many of the health problems encountered in amphibian collections. Where possible, materials and suggested suppliers are listed and in some cases, alternatives are offered for items that may not be available in all areas. At the end of the chapter, an extensive list of Additional Recommended Literature is provided for those who want to fortify their knowledge of amphibian natural history and husbandry techniques. It is recommended to communicate with others who have worked with that species (or closely related species or genera) in captivity and employ their proven techniques and avoid repeating less fruitful methods. If husbandry experience is unavailable for the target species, methods may have to be tested through trial and error and shared with peers. Twenty years ago, relatively little was known about amphibian captive care. More recently, a sort of “renaissance” has occurred in the science of amphibian husbandry and breeding. Yet this area of study is still lagging behind the disciplines of mammalian and avian husbandry especially in the areas of nutrition and veterinary care. It is up to you, the next generation of amphibian scientists to fill in our knowledge gaps and improve a field that is still relatively new. To learn more, the Association of Zoos and Aquarium’s (AZA) Professional Training Program: Amphibian Biology, Conservation, and Management would be an invaluable experience (www.aza.org/ABCM.aspx). The monograph published by this course is a very useful learning tool and many of the topics covered herein are covered there in greater detail. Finally, AZA husbandry manuals for mountain yellow-legged frogs (Rana muscosa), Panamanian golden frogs (Atelopus zeteki), and Puerto Rican crested toads (Peltophryne lemur) recently have been updated and others will soon follow. These manuals are great starting points for any of these species and also provide information applicable to other amphibian propagation programs. The peer-reviewed journal Herpetological Review, published by the Society for the Study of Amphibians and Reptiles (SSAR), is a very useful Amphibian Husbandry Resource Guide, Edition 2.0 5 A publication of AZA’s Amphibian Taxon Advisory Group, 2012 Chapter 1: General Amphibian Husbandry resource for herpetological husbandry and related techniques. This society provides discounted memberships to zookeepers and students (www.ssarherps.org). Planning It is important to consider the overall purpose and long-term goals of keeping a particular species in captivity. Goals can range from maintaining amphibians for educational exhibits to reintroduction programs. In addition, it is imperative to gather as much information about the natural history and environmental parameters of the species of choice before proceeding to acquire animals. Extrapolating from related taxa can be useful in some instances where there exists absolutely no precedent for keeping a species in captivity. Select the most closely related species that is closest geographically to the amphibian of interest. Also, especially when little is known about the species or relatives, research the husbandry parameters of a species that shares a similar natural history to the target taxon. For example, if interested in a tropical frog that lives in the leaf litter and lays its eggs on the forest floor, as a starting point consider duplicating husbandry parameters required for a better-known leaf-litter frog such as dart frogs (Dendrobatidae) which are well described in amphibian husbandry literature. The latest and most thorough references on evolutionary history of Amphibia are those of Frost et al. (2006) and Pyron and Wiens (2011). Current taxonomies are presented on two regularly-maintained websites: www.research.amnh.org/vz/herpetology/amphibia/ and www.amphibiaweb.org. Although the published taxonomies are not without their controversies and in some cases are in conflict, often there is something available in the literature on the captive husbandry of at least one species within any given family. Amphibian Ark offers useful information on specific amphibian species in need of conservation action, projects that need collaborators, and practical web-based tools for planning ex situ programs on their website (www.amphibianark.org). Especially useful on this site are the Program Implementation and Population Management tools. At the end of this chapter we provide an extensive list of in-print references, reliable web resources, and links to products that have been used with success by the authors. Note that the listing of products and suppliers does not imply an AZA or ATAG endorsement. Acquiring Amphibians Obtain amphibians from reliable sources, preferably from captive bred stock or animals that have been harvested in a responsible and sustainable manner. Avoid wild caught amphibians from the pet trade if at all possible but if it is necessary to obtain them from the trade, always request import documentation from the supplier and inquire about the status of the animals being obtained (e.g., how long has the animal been in captivity, what sort of medical treatments have been administered, etc.). Only collect or receive animals from the wild with approval and documentation from the proper authorities. Many states and most countries now require permits for amphibian collection. Moreover, while in the field, one should take measures to prevent the spread of Batrachochytrium dendrobatidis (Bd, the amphibian chytrid fungus) and other potential pathogens such as ranavirus from one area to the next or from one individual to another. In the field, non-powdered latex or vinyl gloves should be worn at all times when handling adult animals and changed between specimens (if handling tadpoles or larvae, use washed, powder-free vinyl gloves only). Limit handling of animals as much as possible. Keep in mind that harmful pathogens or toxic skin secretions could be transferred easily from one animal to the next. Boots, walking sticks, and other field equipment should be cleaned free of all soil and other debris and if possible, sanitized with household bleach (3–6% sodium hypochlorite) to a 10% dilution for 15 minutes between field sites. This concentration should kill Bd along with ranaviruses. Additional fieldwork hygiene protocols can be found in Speare et al. (2004), Zippel et al. (2006), and Pessier and Mendelson (2010). Amphibian Husbandry Resource Guide, Edition 2.0 6 A publication of AZA’s Amphibian Taxon Advisory Group, 2012 Chapter 1: General Amphibian Husbandry Transporting Animals Transporting amphibians from one location to another should be done with care. Prior to shipping, become familiar with the International Air Transport Association (IATA) standards for transportation of live animals by air.1 Specimens should be housed in plastic, disposable deli cups or similar containers with tight-fitting lids. The container should be of a size to hold the animal comfortably, but injury may result if the specimen is allowed large amounts of space to jump. Small holes should be cut into lids to allow for gas exchange. Make sure that the holes are sanded down on the inside of the container or punctured from the inside outwards and do not have sharp edges, as amphibian skin abrades easily. The bottoms of the containers should be lined with moist paper towels and/or well-rinsed, moist sphagnum moss. Animals need to be kept cool (generally 65–75 F/ 18–24 C, depending on the species) during transport, by utilizing insulated packaging such as Styrofoam. First, place animals inside plastic containers inside a small cardboard box and then place this box within a larger insulated box. Spaces between plastic containers should be filled with crumpled newspaper to buffer against excessive movement. In extremely warm ambient conditions, sealable plastic lunch bags filled with ice or cool gel packs can protect against overheating. Wrap any temperature packs in newspaper and place within the outer insulated box, but never directly adjacent to containers containing animals. Animals should be shipped the fastest way possible regardless of expense.2 Slower, more “cost effective” modes of shipment could mean death to the animals, especially during warmer seasons. In temperate climates, it is best to ship animals during the spring or fall, instead of during extreme hot or cold seasons. Although there is a lack of sufficient data to say with certainty how many amphibians die during international transport (Smart and Bride, 1993), some shipments of amphibians have resulted in high mortality due to improper packing (crushing) of animals, overcrowding, overheating, and lack of access to water (Brookland et al., 1985). Basic Needs There are several basic but critically important aspects to keeping amphibians in captivity: 1) enclosures; 2) water (sources and quality); 3) environmental conditions (light, temperature, and humidity); 4) food; 5) natural history and behavior; and 6) veterinary care. Although there are many other nuances of amphibian husbandry to consider, mastering these key parameters for amphibian health, will lay the foundation for maintaining and propagating vigorous animals. This is a general husbandry guide and is merely intended as a starting point for those interested in beginning an amphibian program. Sections addressing breeding methods, larval husbandry, and basic veterinary care are provided at the end. The majority of the world’s amphibian species have never been kept, much less bred, in captivity, so there is still much to learn (Pough, 2007). Keeping new species successfully can take months or even years of careful fine tuning to work out proper husbandry protocols. One should not get discouraged by setbacks. Share the development of any discoveries and new techniques with amphibian- minded colleagues. Consider publishing these findings, or else start a blog, join a listserv, whatever it takes to get the word out! ENCLOSURES While some amphibian species might survive in a minimal enclosure such as a plastic box with paper towel and a hide box, it is important to consider other aspects of the health and well- being that can be addressed through proper housing, substrate, and refugia. These aspects, combined with light, temperature, and humidity can directly contribute to the animals’ ability to thrive in captivity. Enclosures are best planned and built based on the needs of the species, which are directly tied to its natural history, not necessarily its taxonomy. Consequently, there may be enclosures for terrestrial species such as Dendrobates, Mantella, and Megophrys (poison frogs and leaf frogs) that are very different from those for arboreal species such as 1 Purchased from the following: http://www.iata.org/ps/publications/Pages/live-animals.aspx. 2 Explore air freight or express shipping (same-day or over-night) options. Amphibian Husbandry Resource Guide, Edition 2.0 7 A publication of AZA’s Amphibian Taxon Advisory Group, 2012 Chapter 1: General Amphibian Husbandry Gastrotheca or Rhacophorus (marsupial and gliding frogs, respectively). Enclosures for riparian species such as harlequin frogs or fully aquatic species such as Telmatobius are more examples. Preparatory research on natural history for individual species and applying this knowledge to husbandry cannot be stressed enough. Regardless of the size, material, or brand, all enclosures should: Satisfy the physiological and behavioral needs of the animals Prevent escape of specimens and food items Be easy to maintain Make it easy to monitor the animals Construction of Amphibian Enclosures – Materials and Methods Commonly-used amphibian enclosures are constructed of glass, acrylic, fiberglass, or other synthetic materials. Using non-porous, easily cleaned materials is important. All enclosures should be fitted with a tight- fitting (e.g., screen) lid but keep ventilation in mind. Some projects, such as head starting programs for ranids, may require larger (e.g., 250 gallon or larger) enclosures (Figure 1). However, for most indoor Figure 1. The head starting program for Oregon projects, the most commonly used spotted frogs (Rana pretiosa) at the Woodland Park enclosures are over-the-counter glass Zoo uses large Rubbermaid tanks for developing aquariums fitted with screen lids (Figure 2). embryos, eggs, and froglets. (Photo: J. Pramuk) Recently, some companies have begun Figure 2. Schematics of open system (left) and closed system (right) terraria with tight-fitting, ventilated lids. A) Lighting source (e.g., track lights) to maintain plant growth and UVB for amphibians. B) Mist heads, attached to a pump, which deliver aged or filtered water to the terrarium (operated manually or via a timer; open system only). C) Invertebrate food (e.g., vitamin-dusted and gut loaded domestic crickets) adds ammonia to the terrarium from their waste and dead bodies. D) Cage furnishings (e.g., a cut branch from a non-toxic plant). E) Live foliage, which consumes some ammonia and other nitrogenous wastes from the substrate. F) A hiding spot for terrestrial amphibians (e.g., an inverted coconut shell with a door cut into its side). G) A substrate layer (e.g., pea-sized gravel covered with moist sphagnum moss and leaf litter). H) A false bottom, which can be constructed from egg crate or perforated PVC sheeting, sitting atop small supports (e.g., cut pieces of PVC pipe). The false bottom is covered with a sheet of fiberglass window screen to prevent substrate, invertebrates, and animals from reaching the drain and escaping. Note the wastewater reservoir under the false bottom in the closed system. I) The drain, cut through a hole in the bottom of the terrarium and fitted with a bulkhead plumbed to a PVC pipe, which allows excess water and waste to be removed on a continual basis from the open system. J) The terrarium’s resident frog. (Illustration: J. Pramuk) Amphibian Husbandry Resource Guide, Edition 2.0 8 A publication of AZA’s Amphibian Taxon Advisory Group, 2012 Chapter 1: General Amphibian Husbandry manufacturing amphibian-specific terraria3; despite their increased cost (ranging from $40– 300, initial reports are that they are worth the extra expense for ease of cleaning and access. An alternative to glass aquaria are polycarbonate food grade storage containers.4 The lids of these containers can be modified to provide sufficient air exchange by cutting out a portion and gluing in fiberglass window screen with a hot glue gun or silicone aquarium sealant. Although not as aesthetically pleasing as glass enclosures, these serve well as off-exhibit housing. Acrylic or polycarbonate enclosures can be expensive initially, however they are lighter than glass and more resistant to cracking and breaking; in the long run, they are probably more cost effective. The downside of plastic enclosures is that they scratch more readily and require frequent buffing to keep clear. One salamander breeder in the U.S. uses these simple enclosures for an entire colony with great success in maintenance and breeding. For many terrestrial salamanders and smaller terrestrial frogs, 20 gallon Long aquariums with tight fitting lids work well. Arboreal, nervous, and/or jumpy species seem very prone to escape and injury from many enclosures. A method employing a ten-gallon aquarium set on end and outfitted with a front opening door and ventilation area serves well for housing glass frogs (centrolenids) and colonies of juvenile Figure 3. Vertical tanks used for housing arboreal phyllomedusines (Figure 3). Add tree frogs. Note the simplistic set-up including a floor with branches and plants to offer sufficient wet paper towels instead of gravel or soil, which can climbing and perching areas. harbor parasites. (Photo: R. Gagliardo) To Plumb or Not to Plumb? It is important to recognize that any enclosure, regardless of size, shape, or use, represents a living ecosystem whereby resources (animals, water, light, heat, etc.) are added and that as an ecosystem, natural biological processes should be allowed to occur. There are two fundamental types of systems with regards to amphibian enclosures: closed and open (Figure 2). Closed systems do not allow the outflow of water and wastes and thus require close attention to drainage and hygiene. Open systems typically have built-in ways of dispensing of excess waste products through drains, overflows, and the ability to rinse the enclosure easily and frequently on a regular basis. Open systems require more complicated plumbing to allow fresh water in and wastes to exit the system, but the advantages for hygiene are often well worth the extra effort. The decision to build and maintain freestanding (i.e., closed) enclosures or plumbed (i.e., open) terraria will depend on the needs of the project. If the species or program requires highly hygienic conditions, plumbed enclosures are likely to be preferable. This type of terrarium will require greater initial monetary and time investment to set up, but over the long haul, will save time because they are faster to clean. Regardless of if the tank is plumbed or freestanding, several guidelines apply to set up both types of enclosure. 3 ExoTerra® and ZooMed® both sell quality terraria specifically for amphibians. 4 Such as Rubbermaid® or Sterlite® Amphibian Husbandry Resource Guide, Edition 2.0 9 A publication of AZA’s Amphibian Taxon Advisory Group, 2012 Chapter 1: General Amphibian Husbandry Setting Up an Enclosure It is recommended to use a clean substrate, such as gravel or lightweight expanded clay aggregate (LECA) 5, from a reliable source for the bottom of the tank. The substrate provides the basis for a healthy tank ecosystem by creating humidity and harboring beneficial bacteria and small invertebrates that help break down waste. Make a three or four inch (7.5–10 cm) square depression in the gravel or other substrate in one corner of the aquarium's floor or grade the substrate to form a small pool at the shallow end for the animals to access. The gravel layer should be completely covered with at least a one inch (2 cm) thick layer of sphagnum moss or sheet moss. The moss should be soaked overnight and rinsed thoroughly prior to use in an enclosure. Ideally, this sort of environment should be set up at least two weeks prior to introducing animals so that the plants can become established and beneficial bacteria (i.e., natural, biological filtration) will be ready to breakdown wastes. Cork bark and plants can be added to the background, but it is recommended that all or most soil is removed from the roots, as it can harbor potentially harmful parasites such as nematodes. Many bare root plants (e.g., pothos, Spathiphyllum, etc.) will do well when planted in a semi- aquatic environment. The water level in the gravel should be maintained at least 0.6 inch (1.5 cm) below the upper level of the substrate (i.e., sphagnum or sheet moss). Through capillary action, the water will slowly wick its way up through the substrate, offering moist conditions for the plants while the rest evaporates, providing sufficient humidity. Coconut (coco) fiber can also be used as a substrate on top of the gravel and is long-lasting, holds moisture, and is free of unwanted organisms such as worms or flagellates. Because coco fiber is friable, a substrate divider should be used to keep this layer from mixing with the gravel or LECA layer below. Fiberglass window screen or shade-cloth cut to fit the footprint of the tank works well as a divider for the two layers. Live java or cushion moss, or hydrated and rinsed sphagnum moss can be used on top of the coco fiber. Sphagnum moss has an advantage over sheet moss in that the former will usually develop live growth when maintained under high humidity and moderate light. An enclosure outfitted with a false How to Create a False Bottom bottom reduces the weight of the tank Cut a piece of egg crate or a sheet of by allowing the use of less gravel and perforated PVC to the shape of the improves flow through the substrate if a enclosure bottom, forming a false bottom. drain is used (i.e., open system). Cover the false bottom in fiberglass window Alternatively, a similar thickness of LECA screen. substrate (very popular with dart frog Tack the screen onto the false bottom with dabs of silicone or with a soldering iron. culturists) provides a well-drained lower Scatter several one to two inch (2–5 cm) substrate. LECA is slightly more pieces of PVC on the bottom of the expensive than aquarium gravel, but it is enclosure to support a false bottom. much lighter and can be used in Rest the false bottom on top of the PVC situations where weight is an issue. To pieces. raise and separate the amphibians and substrate from the wastewater and The false bottom is now ready to support a drain, create a false bottom using egg substrate layer. crate6 (i.e., sheets of plastic light diffusion grid commonly used with fluorescent lights) or perforated PVC by following the instructions in the box. Plant roots need oxygen and too much water can kill them, so it is important to allow excess water to drain in order to keep the substrate from becoming saturated and anaerobic. Using a 5 Such as Terra Lite® 6 Available at most hardware or lighting specialty stores Amphibian Husbandry Resource Guide, Edition 2.0 10 A publication of AZA’s Amphibian Taxon Advisory Group, 2012
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