LERNAEA (ANCHOR WORM) INVESTIGATIONS IN FISH

An online version journal IJAFS: ISSN 2308-4715, Volume 1 Issue 1 August 2013 Int. j. anim. fish. sci. (Online): 12-19, August 2013, website: www.gurpukur.com or www.gscience.net LERNAEA (ANCHOR WORM) INVESTIGATIONS IN FISH M. M. M. HOSSAIN1*, M. Z. RAHMAN2, M. A. ISLAM3, M. E. ALAM1 and H. RAHMAN1 ABSTRACT Lernaea cyprinacea, a parasitic cyclopoid copepod, is found to parasitize in the broodstock, nursery and culture system in the freshwater hatchery of Jessore regions. The fish were severely infected on their body surface showed dull and sluggish movements. The infected parts of the skin were hemorrhagic, ulcerative along with fibrous nodules. On gross examination of fish numerous grey-black threads like attachments were noticed on the skin which was later identified as crustacean parasite, Lernea sp. (Anchor worm). Lernaea cyprinacea was investigated under culture in more than 30 finfish hatchery and examined in laboratory conditions. The highest infestations (in the summer months) and infections (localized redness, ulcers and inflammation, tiny white-green or red wounds) with Lernaea cyprinacea were observed in Ctenopharyngodon idellus Grass carp, Cyprinus carpio Common carp, Esomus danricus (Flying barb) Darkina, Hypophthalmichthys molitrix Silver carp, Catla catla Catla, Barbodes sarana (Olive barb) Sarpunti, Rasbora daniconius (Slender rasbora) Darkina. Lernea with dioecious (sexes separate) fertilization (internal) and oviparous. The species has nine stages in the life cycle (multistage life cycle), including three free living naupliar stages, five copepodid stages and one adult stage. Adult males die within 24 hours. In one study, the entire life cycle took approximately 18-25 days when fish were held at 29°C. The optimal temperature range for Lernaea is 26-30°C. If temperatures fall below 20°C, juvenile Lernaea are unable to complete their development and at 14°C, females will not reproduce. Lernaea transmission is communication channels (visual, tactile and chemical); perception channels (tactile and chemical). Many kinds of fish are the intermediate and definitive hosts. In the present study, the anterior most region of Lernaea embedded in the host tissue caused more susceptible to secondary infections of bacteria. The infected fish were nervous with dropping scales, bleeding spots, stressed, exhausted and stopped feeding. The tongue like-process ending with the holdfast organ induced necrosis, congestion and tissue proliferation. In the present study, wounds resulting from an infection with Lernaea were closely monitored with optimal water quality and recommended treatment to minimize risk of secondary bacterial and fungal infection (data were not shown), become resistant to future infections with Lernaea. Keywords: Lernaea cyprinacea, Investigations brood stock and Culture pond. INTRODUCTION The lernaeid copepod Lernaea cyprinacea Linnaeus, 1758, often called the anchor worm, is a parasite of freshwater fishes in various regions of the world (Kabata, 1985; Lester and Hayward, 2006). The copepod has been reported from a variety of host species including wild, aquarium, and cultured fishes and even amphibians in the world (Shariff et al., 1986; Lester and Hayward, 2006). Lernaea cyprinacea has been recorded in many places around the world. It has been found in parts of Europe, such as Scandinavia, France, Italy and Germany, all the way to Japan in Japanese eel Anguilla japonica by Harding (1950). The parasite is spread throughout Central Asia as well as in the southern regions of West Siberia. The spread of Lernaea cyprinacea northward is limited by temperature. It is an exceptionally thermophilic organism of southern origin, and it develops successfully only at high temperatures. Temperatures between 23-30°C are the most favorable for development (Baur, 1962). Approximately 110 species of lernaeids (Lernaea and Lernaea-like parasites) have been described. Lernaea cyprinacea (one of the more common species) is found worldwide. It is most common in cyprinids, including koi, common carp, small indigenous species and goldfish; however, it can infect other species of fish and has caused major kills in broodfish in hatchery at Jessore region. Lernaea has also been reported to infest amphibians. In world, various studies on the biology of L. cyprinacea have been conducted to date since the work of Ishii (1915) who recorded it as Lerneocera cyprinacea. Lernaea species, commonly known as “anchorworms” are crustacean, copepod parasites that can infect 1 Dr. Md. Mer Mosharraf Hossain, 1Md. Eftakher Alam and 1Habibur Rahman, Department of Fisheries and Marine Bioscience, Jessore Science and Technology University, Jessore and 2Mohammad Zillur Rahman, Feed the Future Aquaculture Project in Bangladesh, WorldFish Center, Jessore, 3Md. Ariful Islam, (IDRS-BFRI) Project, Shrimp Research Station, Bagerhat, Bangladesh. *Corresponding author’s Email: [email protected] 12 An online version journal IJAFS: ISSN 2308-4715, Volume 1 Issue 1 August 2013 and cause disease and mortality in many types of freshwater fishes (and are not host specific but are particularly common in cyprinids fish) especially wild-caught and pond-raised species. The infested wound caused by the crustaceans often gets infected which is one of the main reason this disease can invite so many other microbial diseases to get sick the infected fish. The present study was designed to investigate the Lernaea transmission, infestations, infection sites; microscopic lesion, clinical signs, life cycle, gross diagnosis, symptoms and pathology, percent of parasites have egg sacs and reproductive capacity of Lernaea. MATERIALS AND METHODS The study was conducted at the Laboratory and Field, Department of Fisheries and Marine Bioscience, Jessore Science and Technology University, Jessore, Bangladesh during January to June 2013. Data were collected from Finfish Hatchery and Feed the Future Aquaculture Project in Bangladesh, World Fish Center at Jessore region of Bangladesh supported by Infrastructural Development and Research Strengthening of the Bangladesh Fisheries Research Institute (IDRS-BFRI) Project, Shrimp Research Station, Bagerhat. Experimental Fish and Grouped: Fish were collected with the help of a drag net from a commercial fish farm and hatchery broodstock in Jessore, Bangladesh. The fish were identified and kept alive in a water container and examined. The parasites were removed with the help of fine forceps and placed in vials containing 5% formalin. Ctenopharyngodon idellus Grass carp, Cyprinus carpio Common carp, Esomus danricus (Flying barb) Darkina, Hypophthalmichthys molitrix Silver carp, Hypophthalmichthys nobilis Bighead carp, Labeo ariza (Reba) Bata, Labeo bata Bata, Labeo calbasu (Orange-fin labeo) Kalibaus, Labeo rohita Rohu, Barbonymus gonionotus (Java barb) Rajputi, Catla catla Catla, Cirrhinus cirrhosus Mrigal, Anabas testudineus (Climbing perch) Koi, Barbodes sarana (Olive barb) Sarpunti, Rasbora daniconius (Slender rasbora) Darkina, Puntius ticto (Ticto barb) Tit punti, Oreochromis niloticus (Nile tilapia) Nilotica, Heteropneustes fossilis (Stinging catfish) Shingi, Clarias batrachus (Walking catfish) Magur infected with Lernaea cyprinacea were collected more than 30 hatchery. Recovered fish group 1 (RFG1) and recovered fish group 2 (RFG 2) and stocked in ten (10) pond and ten (10) laboratory aquarium where the control group was CG to perform efficacy and treatment trail by using different drug and improved management. Sample preparation, visual and microscopic observations: The collected parasites were brought to the Central Biological Laboratory of JSTU and permanent mounts of the parasites were prepared according to Cable (1985). For this purpose, the parasites were washed with distilled water to remove the fixative. The washed specimens were kept in 10% potassium hydroxide until their bodies became transparent. Then the parasites were washed by distilled water to remove the alkali. After washing, Lermaea species were kept in glass slides or in petridishes with DW, specimens were examined under photography microscope (AxioCam ERc 5s with Axio Vision driver, Carl Zeiss, Germany) for their identification in fig. 1 and fig. 2. For the control of this disease the experiments and observation were followed and incubated at water temperature ranged between 150C-310C for 21 days to hatched and produce nauplii stages, after hatching were left for 48 hours to complete molting and produce copepods stages which regard as infective stages and introduced it into ten tanks which containing RFG1, RFG2 and CG. The infective stages of parasite to host and for carrying out the infections egg sacs were carefully removed from adult female copepods to check the life stages using visual and microscopic examination. The nature and attitude, morphological types and reproductive characteristic of Lermaea were also observed. RESULTS AND DISCUSSION Nature and attitude Lernaea live in freshwater habitats (lakes and ponds, rivers and streams, temporary pools, flood lakes and saltier neighboring lakes; 0.071-1.6965% NaCl) ranges temperate and tropical. The salinity of the water affects how well the copepod reproduces. "Sweet water" is the only possible environment for the Lernaea cyprinacea reproduction to be possible. This parasite is motile, sedentary, attaches to the gills 13 An online version journal IJAFS: ISSN 2308-4715, Volume 1 Issue 1 August 2013 of fish and usually lives on the surface of the body. After eating away the scale of the fish, it enters the internal tissues and causes significant structural changes. The fish reacts by trying to isolate the parasite and form a compact sheath. This sheath is made up of a thick layer of epithelial and connective tissues. The formation of this sheath causes the tissues of the fish to swell. These swollen tissues often become stained red with the increased activity of the parasite. The parasites are found on the fish any time of the year, high infestation intensity which leads to death of the fish occurs only in the summer. The male uses its prehensile second antennae to hold on as well as crawl around the body of the female (Baur, 1962 and Yamaguti, 1963). The crustacean Lernaea is often called "anchorworm" by aquarists as it anchors deeply in the fish skin with its branched suction organ and has an elongated body without visible limbs. At the back end, there are two sac-like outgrowths where eggs develop. It takes the eggs between several days and two weeks to attain maturity. Then they fall off and the larvae hatch. The mother crustacean dies and is repelled from the fish tissue after the eggs have fallen off. The larvae are also parasites and go to the gills of the fish to suck blood. As larvae, they attain sexual maturity there. After mating, the female larvae leave the fish and swim around as planktonic organisms for a short time. Then they find a host and bore their way into its skin. One young adult female (Fig. 1A), copepodids (Fig. 1B) and fish with egg sac (Fig. 1C) of Lernaea cyprinacea were found in different fishes but severely in Darkina Rasbora daniconius and Grass carp Ctenopharyngodon idellus. (1A) (1B) (1C) Fig. 1. Lernaea cyprinacea from freshwater fishes of Darkina Rasbora daniconius and Grass carp Ctenopharyngodon idellus in Jessore. Lernaea infestation Infestations (Fig. 2) with Lernaea are most prevalent in the summer months and occur more commonly in stagnant or slow-moving water bodies. The young are free swimming and borrow into the skin, go into the muscles and develop for several months before showing. They release eggs and die. The holes left behind are ugly and may become infected. Male worm die soon after mating, then female burrows into the flesh of a fish (Murphy and Lewbart, 1995) and transforms into an unsegmented wormlike form, usually with a portion hanging from the body of fish, visible to the Naked eye (Schaperclans, 1991) where they live for several months while developing. After developing, they make their way out of the fish, a process that often leaves bad wounds. Right before the anchor worm dies; it will release its eggs. The cycle is then repeated over and over again. Fig. 2. Darkina Rasbora daniconius infestations with anchor worms. 14 An online version journal IJAFS: ISSN 2308-4715, Volume 1 Issue 1 August 2013 Infection sites Anchor worms (Lernea) detected with the naked eye and infection sites also observed with photography microscope found in localized redness, ulcers and inflammation, tiny white-green or red wounds (looks a red sore or pimple) in skin, gills, buccal cavity, scales and muscles in fish with frequent rubbing or "flashing", breathing difficulties and general lethargy (Fig. 3). The anterior part of the body of metamorphosed adult female is embedded in the host tissue (penetrated makes haemorrhages), whereas the remaining body protrudes in the water. Fig. 3. Ctenopharyngodon idellus Grass carp infected with Lernaea cyprinacea. Reproduction Lernea with gonochoric/gonochoristic/dioecious (sexes separate), fertilization (internal) and oviparous. In the fourth copepodid stage, both sexes become sexually mature. In this free-swimming stage the female becomes fertilized and the male dies without developing further. The females seek their second host. Only females are visually seen (Length 10-12 mm). A hatched nauplius grows to the first copepodid which settles on a host fish (Kasahara, 1962). Males detach from the host after the population. This is where the females form their egg sacs. It reproduces at >15oC, stops the reproduction and overwinters at <12oC after 4-5 generation changes. Life cycle of Lernaea The species has nine stages in the life cycle, including three free living naupliar stages, five copepodid stages and one adult stage (Grabda, 1963). After male and female adults mate on the fish host and then males die, females metamorphose, insert their anterior body into the host tissue and then produce eggs (Fig. 4). Lernaea has direct life cycle (do not need to pass through an intermediate host) can take from 18 to 25 days to complete and only a fish (or an amphibian) is necessary for the organism to develop from egg to mature adult. After a male and female parasite mate, the male dies and the female bores into the host tissue, eventually using a large anchor on her anterior (“head”) end to permanently embed into the skin and muscle of the fish (Fig. 4). The female matures into an adult and within 24 hours, may begin to release eggs from a pair of sacs on its posterior (“back”) end (Fig. 4). Each released egg hatches within 24-36 hours. Females are very prolific and can produce batches of up to 250 juveniles (nauplii) every two weeks for up to 16 weeks at temperatures warmer than 25°C. Newly hatched nauplii are free-living (not parasitic) and develop through three different naupliar stages in about 4 days. At that point they molt into the first copepodid stage, become parasitic and attach to a host, often on the gills. Over the next 7 days, the parasite develops through five different “copepodid” stages. The copepodid stages typically are also found on the gills but are not permanently embedded in the tissue. Once in the final copepodid stage, the male detaches, but the female remains parasitic, attached to the current host or moving to another fish. Adult males die within 24 hours. In one study, the entire life cycle took approximately 18-25 days when fish were held at 29°C. The optimal temperature range for Lernaea is 26-30°C. If temperatures fall below 20°C, juvenile Lernaea are unable to complete their development and at 14°C, females will not reproduce. However, adult females can overwinter on the fish host, producing eggs when water temperatures warm up in the spring. 15 An online version journal IJAFS: ISSN 2308-4715, Volume 1 Issue 1 August 2013 Fig. 4 showed Lernaea cyprinacea eggs hatch in 1-3 days. When they hatch they are in the nauplius stage. This is a six-legged elliptical larva. There are three nauplius stages. The first is the oval form, next is the without mouth or labrum form, and the third is a form with a single pair of furcal setae. After 4 to 16 days in the nauplius stage it metamorphoses into the first copepodid stage. After this metamorphosis, no further development occurs unless a host is found. The parasite then attaches to the host and undergoes further transformation. After attaching to the host, the larvae are not able to swim anymore because their appendages are reduced to short stumps and their setae are lost. The larvae spend some time on the host. They then molt. With this process they reform their appendages and acquire the ability to swim again and leave their intermediate host. The larva passes through 5 successive copepodid stages before the female attaches. In the fourth copepodid stage, both sexes become sexually mature. In this free-swimming stage the female becomes fertilized and the male dies without developing further. The females seek their second host. This is where the females form their egg sacs. About 14-28 days are needed to go from hatching to the production of egg sacks, depending on the temperature. In cold temperatures it could take up to a year to produce a new generation. Under natural conditions, however, several generations occur in the course of one year. Throughout its development certain parts of the parasite grow, while other parts are inhibited or even reduced in development. While the organism is in its free-swimming stages of life, its legs are well developed to aid with swimming. In the organism's parasitic stages it is on a host, and does not need these appendages (Calman, 1911; Gurney, 1933; Hoffman, 1967 and Yamaguti, 1963). Fig. 4. Lernaea (anchorworm) life cycle observed under photography microscope (AxioCam ERc 5s with Axio Vision driver, Carl Zeiss, Germany). The entire life cycle may take from 18-25 days at approximately 25-30oC. Transmission and food habits Crustaceans have various sensory resceptors, mainly setae over the body. Photoreceptors are also generally present (Brusca and Brusca, 2003). Communication channels (visual, tactile and chemical); perception channels (tactile and chemical). Many kinds of fish are the intermediate and definitive hosts, primary diet (carnivore; eats body fluids). Mainly these hosts are from the family Cyprinidae. Fish such as Ctenopharyngodon idellus Grass carp, Cyprinus carpio Common carp, Esomus danricus (Flying barb) Darkina, Hypophthalmichthys molitrix Silver carp, Catla catla Catla, Barbodes sarana (Olive barb) Sarpunti, Rasbora daniconius (Slender rasbora) Darkina all are parasitized by Lernaea cyprinacea. Many fish serve as intermediate as well as definitive hosts during heavy infestation. The parasite feeds on the internal tissues of the fish. It attaches to the gill chambers of the fish and parasitizes it externally. This parasite is a big threat because it lacks host specificity to such an extent that it can infect all freshwater fish and even frog tadpoles and salamanders (Baur, 1962; Hoffman, 16 An online version journal IJAFS: ISSN 2308-4715, Volume 1 Issue 1 August 2013 1967). These species are probably preyed on indirectly. Several of the larval stages die due to not reaching a suitable host. Diagnosis (Gross pathology, Microscopic lesions, parasitology and health hazard) The adult female observed in naked eye appears as a small, thin “thread” or “hair” approximately 25 mm long. Under the microscope, the long, tubular body has an anchor on the anterior end and paired egg sacs on the posterior end (Fig. 4). Juvenile life stages, especially the copepodid stages were seen on skin, gill, oral cavity and fins with use of a microscope and examined wet mounts of affected areas (Fig. 3 and fig. 4). Tissues adjacent to the head part of worm become inflamed, which are susceptible to secondary infections of bacteria. In cyprinids, many Lernaea cyprinacea infect the buccal cavity, impairing the feeding activity of the host fish. The postmetamorphic adult females penetrate most of the body surface where the parasite changes gradually into dark reddish or brownish color causing inflammation (of nearly 5 mm bloody ulcers) in skin, fins and muscles at raised temperature to 24°C. The infected fish were nervous with dropping scales and bleeding spots particularly at the bases of fins. They were also stressed, exhausted and stopped feeding. In the present study, the anterior most region of Lernaea embedded in the host tissue caused severe histological alterations. These are oedema along the way of penetration, haemorrhages in tissue surrounding the infection site (Fig. 3) and a fibroid sheath around the head. This caused disruption of the infected tissues in the ulcerative area particularly at the fin base. The tongue like-process ending with the holdfast organ induced congestion and tissue proliferation (Fig. 5). In addition, the holdfast organ of the parasite extended into myofibril tissue of the host trunk that became necrotized and sloughed beside a lot of fat tissue around the attachment site of infection (Fig. 5). Fig. 5. Necrosis, congestion and tissue proliferation in Grass carp Ctenopharyngodon idellus caused by Lernaea cyprinacea. Diseases in fish caused by Lernaea Intense focal inflammation and hemorrhage can occur at the attachment site, making the area appear red and ulcerated. While an infection by small numbers of parasites isn’t necessarily fatal, it is extremely irritating to the fish. Lernaea can cause intense inflammation, leading to secondary bacterial (e.g., Aeromonas hydrophila) and fungal infections (Fig. 6). These secondary infections sometimes worsen and kill the fish. Larger numbers of parasites on the gill can interfere with respiration, causing death. Fish can survive Lernaea infection, but chronic conditions frequently result in poor growth and body condition. Fig. 6. Secondary bacterial (e.g., Aeromonas hydrophila) infection isolated from infested fish. 17 An online version journal IJAFS: ISSN 2308-4715, Volume 1 Issue 1 August 2013 Recommended prevention and control for Lernaeosis Protect rote of transmission (such as: vectors), quarantine and screening, reducing stocking density, maintaining optimum feeding regimes, water exchange, pond dying with soil and water treatment by bleaching powder or chlorine treatment were experimentally observed for best Lernaeosis prevention. In the present study, for individual lernaeids were removed from the affected fish using forceps. However, the removal is not always complete; sometimes the anchor portion remains embedded. The forceps method is impractical on a large scale and other methods are recommended, the following recommendations were experimentally practicing in vitro conditions depending upon the fish species and the situation. Dimilin Powder (dimilin®, diflubenzuron or agricultural dimilin or lufenuron or benzoylphenylurea): which are not true-pesticides but are regarded as IDI (Insect Development Inhibitors) chitin (insect exoskeleton is a substance called chitin) inhibitor was used in laboratory conditions to treated Lernaea infections. Dimilin is assumed to interrupt the parasite’s life cycle and reproductive processes, Diflubenzuron (dimilin) works by interfering with the development of the new chitin exoskeleton, shed their exoskeleton, they die because the new exoskeleton is not properly formed. Potassium Permanganate is another way of removing anchor worm. Sera Baktopur was used to treat the wounds of the fish after the anchor worms. PimaFix (melafix), oxytetracycline and tetracycline for secondary infection (bacterial infections). Copper Sulfate in ethanol and Methylene blue after physically remove them with tweezers and disinfect the wounds. In one salinity study with L. cyprinacea, a percentage of adult females survived fairly prolonged exposure, up to 22.4g/L seawater (ppt) for up to 6 days. At 25.6 ppt adults were killed by day 2. On the other hand, hatching of lernaeid eggs did not occur at 8g/L seawater, and development of younger life stages that did hatch was prevented if the parasites were exposed for at least 5-6 days at 4.8g/L. Dipping of freshwater fish in saltwater (2.5-3%) concentration Lernaea infection was successfully controlled by gradually changing the water salinity to 10 ppt for 21 days. Malachite green, masoten, aspirin, formalin dip and organophosphate insecticides (trichlorfon) were also use to break the lernaeid life cycle within the tank. Biological control of larval stages of L. cyprinacea by using predatory free-living cyclopoid copepods and culture of darkina Rasbora daniconius (more susceptible for Lernaea infection) to protect other cyprinids culture has been practiced in this study. CONCLUSION Lernaea infestations are particularly common in cyprinids; including koi, goldfish, and other related carp, although numerous other freshwater species are susceptible (Baur, 1962). Individual parasites can cause severe focal damage to affected tissue, increasing the risk of infection by bacterial and fungal pathogens present in the environment. Several effective therapies are available for control of lernaeids; however, options are very limited for food fish and pond production. Quarantine and screening of incoming fish are highly recommended to avoid introduction of the parasite. In this study the rejection of Lernaea cyprinacea from skin of fishes, however, rejection of these copepods is believed to be due in part to cellular and inflammatory responses, these responses occurring in attachment site of parasites during infection by it or possible removal by the fish rubbing their bodies against the tanks. Wounds resulting from an infection with Lernaea should be closely monitored and optimal water quality and above recommended treatment should be maintained for the duration of treatment to minimize risk of secondary bacterial and fungal infection. Interestingly, there is evidence suggesting that successfully treated fish may become resistant to future infections with Lernaea. REFERENCES Baur, O. 1962. Parasites of Freshwater Fish and the Biological Basis for thier Control. Bulletin of the State Scientific Research Institute of Lake and River Fisheries, XLIX: 108-112. Brusca, R., G. Brusca. 2003. Invertebrates. Sunderland, Massachusetts: Sinauer Associates, Inc. Cable, R. M. 1985. Am illustrated Laboratory manual of Parasitology, Surjeet Publication, Dehli, pp. 225-256. 18 An online version journal IJAFS: ISSN 2308-4715, Volume 1 Issue 1 August 2013 Calman, W. 1911. The Life of Crustacea. London: Methuen & Co. Ltd. Grabda, J. 1963. Life cycle and morphogenesis of Lernaea cyprinacea. Acta Parasitologica Polonica,11: 169-198. Gurney, R. 1933. British Fresh-Water Copepoda Vol.III. London: Dulau & Co. Ltd. Harding, J. P. 1950. On some species of Lernaea. Bulletin of the British Museum (Natural History), Zoology, 1: 3-27. Hoffman, G. 1967. Parasites of North American Freshwater Fishes. Berkeley and Los Angeles: University of California Press. Ishii, S.1915. Lernaeocera infesting the crucian carp. Dobutsugaku Zasshi (Zoological Magazine), 27: 458-460. (In Japanese). Kabata, Z. 1985. Parasites and diseases of fish cultured in the tropics. Taylor and Francis, London. Kasahara, S. 1962. Studies on the biology of the parasitic copepod Lernaea cyprinacea LINNAEUS and the methods for controlling this parasite in fish-culture ponds. Contributions of the Fisheries Laboratory Faculty of Agriculture University of Tokyo 3:103-196. Lester, R. J. G. and C. J. Hayward. 2006. Phylum Arthropoda. In Fish Diseases and Disorders, vol. 1: protozoan and metazoan infections, second ed. P.T.K. Woo, editor. CAB International, London, England. pp. 466– 565. Murphy, K. M. and G. A. Lewbart. 1995. Aquarium Fish Dermatologic Diseases. Seminars in Avian and Exotic pet medicine. 4(4): 220-233. Paperna, I. and D. E. Zwerner. 1982. Host parasite relationship of Ergasilus labracis KrØyer (Cyclopidea: Ergasilidae) and the striped bass, Morone saxatilis (Walbaum) from the lower Chesapeake Bay. Annis parasit. Hum. Comp. 57: 393-405. Schaperclans, W. 1991. Fish Diseases, Vol. 1, 5th ed. Oxonian Press Pvt. Ltd., New Delhi. Shariff, M., Kabata, Z. & Sommerville, C. (1986). Host susceptibility to Lernaea cyprinacea L. and its treatment in a large aquarium system. Journal of Fish Diseases, 12: 393-401. Yamaguti, S. 1963. Parasitic Copepoda and Branchiura of Fishes. New York, London, and Sydney: Interscience Publishers. 19 View publication stats