An important aspect of approaching any fieldwork with fish and other aquatic species is

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1 REVIEW VETERINARY WORK IN THE FIELD WITH FISH AND OTHER AQUATIC SPECIES Peter W. Scott, MSc, BVSc, FRCVS Abstract Veterinarians who work with fish and other aquatic species often must perform examinations, diagnostic investigations, and treatments away from the clinic or laboratory. Careful planning is important, and attention to biosecurity is essential. Various items of equipment form part of the field kit for such work and range from measuring scales to surgical instruments and anesthetic agents. Excellent recordkeeping at the site is essential. Copyright 2013 Elsevier Inc. All rights reserved. Key words: biosecurity; equipment; fieldwork; fish; recordkeeping An important aspect of approaching any fieldwork with fish and other aquatic species is planning. Whether a visit is made to a suburban pond, rural fish farm, public aquarium, mountain stream, or volcanic lake, some prior consideration regarding a plan of action is needed. Having a clearly established plan of what is to be achieved and what samples or data are to be collected is crucial to success; how these goals are realized on site will inevitably differ depending on location. Veterinarians are now involved in an extensive range of work that includes examining a sick goldfish in a tank or pond, 1,2 treating a valuable collection of koi carp, and working with aquarists and diver teams in public aquaria to capture, restrain, conduct sampling of, and perform surgery on specimens as diverse as eels and large sharks. The diversity in veterinarians treating aquatic species may also involve work on field projects where fish are caught in the wild, anesthetized, and sexed laparoscopically to select breeding stock for captive projects. 3 Being generally informed about the site is valuable, but if the mission is a clinical call to an aquaculture or recreational fish-based site, then taking a detailed history before the visit is essential. This enables the veterinarian to perform appropriate pre-visit research into the history of the problem or work, thereby determining what is needed (e.g., special equipment) to successfully accomplish the work required. Some practitioners work from fully equipped mobile laboratories specifically and completely equipped for the type of work they undertake. This is an ideal that few will achieve. It is more likely that equipment for aquatic veterinary practice will be selected from what is available at the clinic or unit base. Examples of suitable equipment and its use in the field are given in Figs. 1, 2, 3, 4, and 5. BIOSECURITY Biosecurity must be considered when making a veterinary visit to treat any animal species on location. 4 It is especially important in aquaculture or perhaps remote wild sites but still must be considered for the garden pond. There is now sufficient knowledge to underline the need for taking proper measures to ensure that the veterinary surgeon/clinician is not a vector for pathogens moving between sites. There are a range of definitions of biosecurity for different audiences. A simple definition of biosecurity is the sum of From BIOTOPE: Specialist Veterinary Consultancy, Winchester, UK. Address correspondence to: Peter W. Scott, MSc, BVSc, FRCVS, BIOTOPE: Specialist Veterinary Consultancy, Unit 2, Barfield Close, Bar End, Winchester, S23 7LS, UK. pscott@zavg.co.uk Elsevier Inc. All rights reserved /13/2201-$ Journal of Exotic Pet Medicine 22 (2013), pp 46 50

2 FIGURE 1. The author s favored go-everywhere field kit includes resealable plastic bags and gloves, a McArthur microscope, Lovibond comparator water testing equipment, and a hand lens. Also inside the kit are surgical instruments: priest, rat-toothed forceps, dental elevators used as scrapers, Mayo scissors, and pointed scissors. risk management practices in defense against biological threats ; an alternative is the protection of people, animals, and ecological systems against disease and other biological threats. For the fish-keeper/manager, biosecurity means reducing inputs (e.g., food sources, visitors, new fish, quarantine) to a site wherever possible. It requires knowledge of potential uncontrolled inputs along the watercourse perhaps farms, businesses, and sewage processing upstream to be able to assess risk. Disinfection of vehicles is usually required before they can be allowed onto aquaculture sites; equipment must be disinfected between visits. 5 Appropriate overshoes, boots, and coveralls are also considered a necessity in the prevention of disease transmission to and between animal facilities. If multiple visits are to FIGURE 3. Extending tape measures can be useful for large fish. Glass Petri dishes are better to work with, but plastic Petri dishes are lighter in weight and can be discarded after use. be made in 1 day, then a thorough car wash or use of a lay-by where disinfectant sprays can be used is helpful. The ability to wipe down any equipment that is used on site and then hold it in a dirty / contaminated store is useful. Disposable disinfectant wipes can be used, and if these cannot be disposed of on site, a suitable disposal container should be included in the travel kit. Reviews of suitable disinfectants have been carried out, and Virkon Aquatic (DuPont Animal Health, Suffolk, UK) 6 has been identified as an appropriate solution to kill microorganisms. In the clinical situation, it appears to have an ideal FIGURE 2. Rulers or fish-measuring boards are useful for determining the exact size of fish that are to be tested or examined. FIGURE 4. Blood sampling of fish on site. Scott/Journal of Exotic Pet Medicine 22 (2013), pp

3 EQUIPMENT FIGURE 5. The rear space of a Land Rover Discovery provides an excellent flexible working area for work on live and dead fish. spectrum of activity, is available in easy-to-use tablet form, and has low toxicity if spillages occur. Tyvec suits 7 are available in a range of sizes should they be required for the visit. Equipment required on a site visit, in most cases, is relatively basic (Tables 1 and 2). 8,9 A selection of plastic boxes is required; these are available in standard sizes and are cost-effective. They can be discarded where disinfection is difficult (e.g., hinges) or when they become scratched and present an unprofessional appearance. Field microscopes, such as the McArthur microscope, are often required for onsite examination (also discussed by J.E. Cooper in this issue). However, providing good illumination for the microscope can be a problem if there is no power available. Examination of fish will usually require nets and suitable holding containers and, often, anesthesia. Liquid anesthetics (e.g., pre-dissolved benzocaine, phenoxyethanol, eugenol) are popular for site visits because they can be easily measured and adjusted to a variety of container sizes. 10 Aquaculture sites and pet owners will often, but not TABLE 1. Considerations when arranging visit Information to establish before visit Site Location, post code, and grid reference Staff available on site Access (also discussed by M.E. Cooper in this issue) Services Availability of electricity, washing water, and working area on site Equipment Establish biosecurity level or any special needs or considerations Species Clinical data Disease history Current problems Description Site registration details for aquaculture units If sites are in remote or difficult-to-access locations, minimal equipment may be all that one can bring. This problem should be known in advance. Four-wheel drive vehicles may be indicated. Domestic ponds and public aquaria will have suitable power sources and work areas. Some aquaculture sites and most wild sites will not. Availability of nets and examination/assessment tanks for capture and anesthesia Some aquaculture sites may refuse visits if other sites have been visited within h. One should determine whether there any restrictions in removing samples from a site or transporting them to laboratories. Live fish transport may be prohibited; tissues from CITES-listed species may need prior paperwork (also discussed by M.E. Cooper in this issue). Knowledge of species and size range As full a history as possible Water sources and chemistry Pollution incidents New introductions of fish and their sources Prior treatments Feeds used Recent management activities (e.g., handling, cleaning of tanks) that are common stressors Changes in weather, especially if sudden 48 Scott/Journal of Exotic Pet Medicine 22 (2013), pp 46 50

4 TABLE 2. Recommended instruments and equipment Equipment Dissection instruments (multiple sets, ideally packed separately); typically, Mayo scissors, pointed scissors, fine rat-toothed and plain forceps, and choice of fish mucus sampler A hand-lens is often extremely useful. Dissection boards (colored plastic chopping boards are ideal) Range of plastic boxes Box specifically for dirty instruments, dissection board, and so on Sharps container Adhesive labels and tape Permanent markers (often safer than labels) Bottled water is useful at some remote sites for preparing wet smears. Water test kits (hardness, ph, ammonia, nitrite, nitrate): Various types are available, from basic hobbyist level to professional. Generally, those working in field biology or aquaculture will use professional-grade kits and often carry an oxygen meter. Oxygen meters and thermometers will often be available on aquaculture sites. Digital camera and ruler Microscope slide transport boxes Weighing scales Consumables 20-mL universal containers containing 10% formal saline solution, 70% ethanol, or empty (dry, sterile) Transport medium swabs or preferred plates for onsite inoculation before incubation Viral transport medium as agreed upon with laboratory that will be receiving samples Disposable scalpel blades Hypodermic needles and syringes Microscope slides and coverslips Appropriate drugs if required Ziploc plastic bags, as well as bags or other containers for transporting live fish or killed fish in some form of cool bag Anesthetic agent or agents of choice Choice of drugs (e.g., amoxicillin, long acting; enrofloxacin; oxytetracycline): This will very much depend on the purpose of the visit. A wide range of compounds are used in the treatment of aquatic species, from simple salt to antibiotics; national legislation may impact use of some of them. 18 Paper towels Waterproof writing paper always, have their own suitable nets and containers that can be used. A variety of dissection/surgical instruments will be required; multiple sets should be maintained, at the ready, if additional high-risk visits are to be made on the same day. Onsite disinfection of dissection/surgical instruments is a second option. Long-term soaking in disinfectant between sites is rarely recommended because this procedure has a tendency to dull the edges of surgical instruments. For sampling of gill or skin mucus, the author has a favorite tool, a particular dental elevator with a gentle edge that can be used without damaging skin or gills when fish are to be returned to the water. In the majority of cases, having a digital camera available and a ruler to use as a scale and/or obtain measurements will be worthwhile. Battery-powered precision scales are available, or a range of ornithological spring balances can be used for weighing fish on site. THE VISIT Generally, a clinical visit will proceed with more fact finding by the veterinarian from the person overseeing the facility. Establishing a working base a location where fish can be initially examined, transferred to an anesthetic tank, or sampled is important. Basic light scrapings can be collected from most fish while they are conscious, with the appropriate tool (as discussed earlier). Turning fish over manually and holding them against toweling padding can induce tonic immobility; this generally works well in cyprinids and sharks. For large species, injectable anesthesia may be required, and for smaller species weighing less than 10 to 15 kg, immersion anesthetics are recommended, in part because recov- Scott/Journal of Exotic Pet Medicine 22 (2013), pp

5 ery is shorter. For euthanasia, an overdose of an anesthetic agent is least damaging to tissue, whereas concussive techniques usually traumatize gill tissues. Taking appropriate and full records is extremely important for problem assessment. Because the operator usually has wet hands, one should delegate this task for the best results. When performing fieldwork in winter, it is wise to use waterproof paper. Recording basic data such as standard length and weight plus any relevant findings is typical protocol. Standard postmortem examination procedures are available and readily accessible. 11 Collecting parasites or other samples in the field can require special techniques for preservation and identification. If this is anticipated, then specialist sources should be consulted However, field guides can be of use for the less experienced veterinarian or if a specialist cannot be contacted in an expeditious manner. 17 REFERENCES 1. Lewbart GA: Koi medicine and management. Suppl Compend Contin Educ Pract Vet 20:5-12, Roberts HE (ed): Fundamentals of Ornamental Fish Health. Oxford, UK, Wiley-Blackwell Publishing, Divers SJ, Boone SS, Hoover JJ, et al: Field endoscopy for identifying gender, reproductive stage and gonadal anomalies in free-ranging sturgeon (Scaphirhynchus) from the lower Mississippi River. J Appl Ichthyol 25(Suppl 2):68-74, Scarfe AD, Lee CS, O Bryen PJ (eds): Aquaculture Biosecurity: Prevention, Control, and Eradication of Aquatic Animal Disease. Oxford, UK, Blackwell Publishing, Francis-Floyd R: Sanitation Practices for Aquaculture Facilities. College of Veterinary Medicine, Florida Cooperative Extension Service, Agriculture and Resource Management Council of Australia and New Zealand: AUSVETPLAN: Operational Procedures Manual Decontamination. Agriculture and Resource Management Council of Australia and New Zealand, DuPont Biosecurity Products. Emergency_Disease_Control/en_US/products/product.html. Accessed November 3, Cooper JE, Samour JH: Portable and field equipment for avian veterinary work. Proc 4th Conf European Comm Assoc Avian Vet, London, UK, Frye FL, Cooper JE, Keymer IF: Outfitting and employing a compact field laboratory. Zoomed Bull BVZS 1:28-36, Ross LG, Ross B: Anaesthetic & Sedative Techniques for Aquatic Animals (ed 2). Oxford, UK, Blackwell Publishing, Yanong RPE: Necropsy techniques for fish. Semin Avian Exot Pet Med 12:89-105, Chubb JC, Pool DW, Veltkamp CJ: A key to the species of cestodes (tapeworms) parasitic in British and Irish freshwater fishes. J Fish Biol 31: , Brown AF: A key to the species of Acanthocephala parasitic in British freshwater fishes. J Fish Biol 28: , Justine J-L, Briand MJ, Bray RA: A quick and simple method, usable in the field, for collecting parasites in suitable condition for both morphological and molecular studies. Parasitol Res 111: , Yasutake WT: Collection and preparation of fish for histological examination. US Fish Wildl Serv Fish Wildl Leafl 11, Pritchard MH, Kruse GOW: The Collection and Preservation of Animal Parasites. Lincoln, NE, University of Nebraska Press, Pouder DB, Curtis EW, Yanong RPE: Common Freshwater Fish Parasites Pictorial Guide: A Series Covering Sessile ciliates, Motile ciliates, Dinoflagellates, Coccidia, Microsporidians, & Myxozoans, Monogeneans, Digenean Trematodes Nematodes, Acanthocephalans, Cestodes, Leeches, & Pentastomes and Crustaceans. Gainesville, FL, Institute of Food and Agricultural Services Extension, University of Florida, Treves-Brown KM: Applied Fish Pharmacology. Alphen aan den Rijn, Netherlands, Kluwer Academic Publishers, Scott/Journal of Exotic Pet Medicine 22 (2013), p 46 50