JECET; September 2013 – November 2013; Vol.2.No.4, 1294-1300.
Journal of Environmental Science, Computer Science and Engineering & Technology
An International Peer Review E-3 Journal of Sciences and Technology
Available online at www.jecet.org Environmental Science
Research Article
An Investigation on Argulus Foliaceus Infection of Rainbow Trout (Oncorhynchus Mykiss) in Artificial
Lake Amghass II Province Ifrane Morocco
Aba Mustapha1*, Belghyti Driss1, Elkharrim Khadija1, Loukili abdechahid1 , Benabid Mohammed2
1Biology and Health Laboratory, Environmental and Parasitology Team/UFR Doctoral, Sciences Faculty, Ibn Tofail University, Kénitra B.P. 133, 14000, Morocco.
2 National Centres of Hydrobiology and Pisciculture (Nchp) Azrou 53100 Morocco.
Received: 13 October 2013; Revised: 30 October 2013; Accepted: 6 November 2013
Abstract:Infectious diseases of fish are broadly categorized as parasitic, bacterial, viral, or fungal. The genus Argulus (Crustacea: Branchiura), or fish louse, are common parasites of freshwater fish. The aim of present study was to determine the prevalence, abundance and mean intensity of Argulus in rainbow trout at differents part of this fish in middle atlas at city Azrou province of Ifrane Morocco.
Investigations on the occurrence of Argulus foliaceus from fish caught in the lake situated at 22 Km to the southwest of Azrou city centre , revealed that on A total of 170 rainbow trout (Oncorhynchus mykiss) were examined for ectoparasites.The parasites collected from the skin and fins of fish and gills were identified as Argulus foliaceus . Obtained results revealed that, the highest infection rate was recorded among the large rainbow trout and the distribution of parasites was not uniform on different parts of body fishes.
Keywords: rainbow trout, ectoparasite, agrulus foliaceus, prevalence, abundance, mean intensity,lake.
INTRODUCTION
Parasites can be divided into two groups based on their location: endo-parasites, where parasitic individuals live internally, and ecto-parasites, where the parasite lives externally
1.Parasites of fish cause high commercial losses in both the aquaculture2 ,fisheries industries and recreational fishery operations3,4.
Fish lice of the genus Argulus are ectoparasitic on primarily freshwater and marine fish5. Their ability to propagate and affect different fish species. These parasites cause economic loss by affecting the health of fishes, often cause high mortality6-9. Argulus foliaceus L., is one of the most widespread crustacean ectoparasites of freshwater fish in the world in terms of both distribution and wide variety of fish it infests7,10-12. The effects of Argulus parasites on their fish hosts are quite diverse and range from physical damage caused by attachment and feeding activities of the lice to behavioural changes associated with stress. The parasite Argulus foliaceus is a crustacean parasite which can swim from host to host attaching itself with strong sukers and puncturing the fishes skin with a poison spine.
Symptoms include scraping, scratching small sores and the appearance of the parasite itself13. This parasite infected the skin, fins and gills of the freshwater fishes hosts14. This parasite, recognized as a scourge of freshwater fish worldwide, is considered as a major economic problem especially for rainbow trout . The direct and indirect results of louse infections can still be significantly costly to aquaculture and sport fishing operations for this fish3.
Despite the opportunistic nature of this parasite some hosts still appear to be more susceptible than others15. In this investigation we analysed a rainbow trout population from a recreational fishing lake in the Middle Atlas near the city of Azrou Morocco.Argulus foliaceus was observed for the first time in Morocco at some freshwater fishes in rainbow trout16 in 1996 , in Amghass II Province of Ifrane.
Argulus sp. are found nearly worldwide with about 150 species known at present. Three species documented in world are Argulus foliaceus, Argulus japonicus and Argulus coregoni. Argulus foliaceus also occurs on rainbow trout, as well as perch, tench, carp, pike and bream. The main objective of present study was to determine the prevalence, abundance and mean intensity of Argulus in Rainbow trout of water bodie at Amghass II province of Ifrane Morocco.
MATERIAL AND METHODS
Study site: Investigations took place in artificial Lake Amghass II (33°23' N et 5° 27' W ), which is located in southwest city of Azrou, Province Ifrane Morocco. This ecosystem was situated at about 22 Km from Azrou. This artificial lake or water bodie, its surface area is 3,2 ha, average maximum depth 3,10 m. Secchi disk visibility ranges from 300 to 310 cm. This site is recognized for sport fishing operations for rainbow trout in Morocco.
Fish sampling: The fish were caught by electrofishing, the fishes were caught from various lake locations. Captured fish were immediately placed in a tank containing water collected from the same location and then transported to the laboratory. During the present study a total of 170 fish were studied to investigate of ectoparasitic infestation in rainbow trout (all age classes).
Parasitological Examination: The investigation was carried out during the summer months 2005, the seasons when the parasite is known to be the most abundant12. The external surfaces of fish were examined thoroughly for individuals’ parasites. The infected fishes were brought to National Hydrobiology Pisciculture Centre (NHPC) Laboratory, Azrou for further examination and identification has been done according to the key by Rushton-Mellor17.
In the laboratory of CNHP of Azrou, The Fishes were weighed, measured and were thoroughly examined for ectoparasites using a hand lens. Smear of scrapings from the skin, fins and gills were made with scalpels and placed on slides. A drop of sodium chloride solution was added to each scrapping, covered with a cover slip and mounted under a microscope and examined for ectoparasites.
This method of obtaining parasites was made separately for fish samples from the aquatic ecosystem described by Paperna18. The parasites were isolated, counted and preserved in 70% alcohol.
Identification of parasite: Identification of the external parasites on the skin, fins and gills of the samples. Parasites found were counted for each fish and were preserved in alcohol (70%). The body surface (skin), fins and gills were examined for parasitic infection, any lesion or any other clinical sign. The parasites were identified according to particularly to Bykhovskaya-Pavlovskaya et al. 19 and Rushton-Mellor17.
Determination of prevalence, abundance and intensity: Parasite abundance (number of parasites per host individual), mean intensity (total number of parasite per number of infected fish) and prevalence (percentage of infected individuals) were calculated according to Bush et al.20 .
RESULTS AND DISCUSSION
Water temperature during the sampling period ranged between 15.5°C and 19.5°C. Morphological description of the parasite can be expressed as follows; a wide, oval body flattened dorso-ventrally, 2 complex faceted eyes. A distinguishing characteristic of this parasite is the urosome, consisting of rounded lobes that are covered marginally with small spines. The posterior incisures of the urosome do not reach to the center. Another characteristic is the anterior portion of the cephalothorax that forms a broad protrusion with shallow grooves. Adults use suction discs for host attachment, whereas larvae utilize larval hooks21, 22.
The causative agent of argulosis was identified as Argulus foliaceus, commonly called fish lice.
Argulus foliaceus were identified according to particularly to Bykhovskaya-Pavlovskaya et al.19 and Rushton-Mellor 17.
In this study it was noted that these parasites of fishes cause clinical signs that observed on the infected fishes, fishes become dull and feeble, rest frequently near the surface of the water, while every movement becomes more difficult and the animals die from complete exhaustion 23. The fins are held close to the body. Skin becomes slimy than normal with the appearance of small blood spots. The gills are expanded and become very pale.
The result of the external examination of these fishes demonstrated that of 170 investigated rainbow trout, 29 specimens were infested with Argulus foliaceus. The skin of infected fishes showed hemorrhagic foci with increase of mucous secretion. Also, redness a round areas on the base of fins were noticed. Gills of infected fishes presented hyperemic areas with increase in mucous secretion.
Infestation value is shown in Table 1.
Table- 1: Prevalence, abundance and intensity of ectoparasitic infestation.
Fish length groups (cm)
No. of fishes examined
No. of infected host
No.of parasites recovered
Prevalence
(%) Abundance Mean density
16 - 25 35 2 7 5,7 0,2 3,5
26 - 35 45 6 28 13,3 0,62 4,67
36 - 45 35 7 43 20 1,22 6,14
> 46 55 14 93 25,45 1,69 6,64
During the study period, the highest number of parasites (93) was collected in large fish and lowest for small fish.The highest number (93) of the species Argulus foliaceus was found for high size of fish. The highest prevalence (25%) and mean density (6.64) of parasites were found in the fish with the large size, and the fishes of intermediate size groups were more infested by parasites compared
with small fish. The maximum abundance of parasites was recorded from larger length group (>35cm) in comparison with the two other groups.
Table- 2: Site of attachment of Argulus foliaceus on rainbow trout.
Infect.fish No. Of parasites Mean intensity Skin fins gills 29 171 5,90 82,53 % 15,62 % 1,75 %
Argulus foliaceus were attached on the body, fins and gills of the fish. Skin harboured higher number of parasites (82.53%) compared to all the fins (15.62%) and gills (1.75%) (Table 2).
The results of the present study demonstrated that the rainbow trout were infected with The crustasean parasites. The fluctuation of prevalence of parasites in different length groups of rainbow trout of the present study demonstrated that the highest prevalence of parasites (25,45%) was recorded from fish samples belonging to the larger length group (>35cm) and the lowest (5,7%) was recorded from fish samples belonging to the smaller length group (16-25cm). So, higher infection was recorded from fishes of the larger length group more than the smaller and medium length groups, due to the increase of the surface area of the infected fishes exposed to parasites. The present finding agrees with those of Al zubaidy24 whose work has been done on carps.
This study may reveal that the parasite loads on fish have been shown to be influenced by the size of the host (Kabata,25; Grutter26 . The size of individual hosts also influences parasite distribution within a host population. Grutter 26found a positive correlation between host fish length and gnathiid parasite loads. Rózsa27 during his investigation showed that wing-feather mite abundance correlates with the body mass of their bird hosts. Poulin28 demonstrated that for copepod ectoparasites of fish both parasite prevalence and intensity correlate positively with host body size. However, Poulin29showed that the nature of the relationship between intensity of infection and host size depends on the individual host and parasite species involved. and our results agree well with those of these researchers
Parasite loads on fish have been shown to be influenced by the size of the host 25(Kabata, 1981;
Grutter26. Which shows that the size of individual hosts also influences parasite distribution within a host population? Grutter26 found a positive correlation between host fish length and gnathiid parasite loads. Rózsa27 during his investigation showed that wing-feather mite abundance correlates with the body mass of their bird hosts. Poulin28 during his research demonstrated that for copepod ectoparasites of fish both parasite prevalence and intensity correlate positively with host body size.
However, Poulin29 showed that the nature of the relationship between intensity of infection and host size depends on the individual host and parasite species involved.
The higher infection was recorded from fishes of the larger length group more than the smaller and medium length groups, due to the increase of the surface area of the infected fishes exposed to parasites30.
For many parasite species the infection intensity is often related to the size of the host.The general trend is that a larger host will harbour higher numbers of ectoparasites30. The reasons for this may be partly related to the hosts age with older hosts, and partly related to the surface area of the host as a larger host has a larger surface area making it easier for parasites to locate and attach to them30,31.
Mikheev et al.6 , observed a similar result for roach, Rutilus rutilus (L., 1758). Similarly,the results of the present study have demonstrated the presence of this parasite in different habitats: skin, fins, gills , are reported on common carp (Cyprinus carpio) by Pojmanska and Chabros32 .
Öztürk and Bulut33, Walker et al.34 reported that A. foliaceus shows higher prevalence, abundance and intensity on larger fish. This is due to the fact that lager fish have a greater surface area and therefore are easier for A. foliaceus to locate on and attach to. Comparable to our results are obtained by Iqbal Zafari et al,34, whose work has been done on black moor and shubunkin two varieties of goldfish, Carassius auratus L. and the third fish koi, a variety of Cyprinus carpio L
CONCLUSION
Fish parasites are of economic importance because they lower the quality of the fish meat. It is therefore important that those responsible for the aquatic environment should endeavor to reduce or eliminate environmental factors and conditions that would favour increase in parasites infestation on fish as observed in this artificial lake. These measures being good lake management strategy could reduce parasitic epizootic and mortality in fish in this aquatic ecosystem.
This study has highlighted the need to continue investigations into this fascinating and economically important group of parasites. .As such it is important to rapidly gain an understanding of the ways in which these animals can affect their hosts. We must also continue to gather intelligence regarding these animals biology and how environmental factors such as temperature can affect this.
It is hoped, therefore, that this study will make a contribution to the literature of what we know about the extremely dangerous infestation of the Argulus foliaceus parasites on the fish population of rainbow trout, specifically in water bodie of Amghass II in Morocco.
REFERENCES
1. M.Friend, J.C. Franson, Field Manual of Wildlife Diseases: General Field Procedures and Diseases of Birds. Information and Technology Report, 1999-001, Washington, D.C.: U.S. Department of the Interior and U.S. Geological Survey.1999, 438p.
2. J.Menezes, M.A.Ramos, T.G. Pereira and A.Moreira da Silva, Rainbow trout culture failure in a small lake as a result of massive parasitosis related to careless introductions. Aquaculture.1990. 89, 123-126.
3. N.G.H.Taylor, C. Sommerville, R.Wooten, The epidemiology of Argulus spp. (Crustacea: Branchiura) infections in Stillwater trout fisheries. Journal of Fish Diseases.2006, 29, 193-200.
4. M.Krkošek,J.S. Ford,A. Morton,S. Lele, R.A. Myers and Lewis, M. A. Declining wild salmon populations in relation to parasites from farm salmon. Science.2007. 318, 1772-1775.
5. G.C.Kearn Leeches, lice and lampreys: a natural history of skin and gill parasites of fishes. Springer, Netherlands.2004.
6. V.N.Mikheev,A.F. Pasternak,E.T. Valtonen. How do fish ectoparasites Argulus spp. (Crustacea:
Branchiura) match with their hosts at the behavioural and ecological scales? Zhurnal Obshchei Biologii.2003. 64, 238-247.
7. M. Krkošek, M.A.Lewis, J.P.Volpe. Transmission dynamics of parasitic sea lice from farm to wild salmon. Proceedings of the Royal Society of London. Series B, Biological Sciences.2004. 272, 689-96.
8. T.Hakalahti, A.F.Pasternak, E.T.Valtonen. Seasonal dynamics of egg laying and egg-laying strategy of the ectoparasite Argulus coregoni (Crustacea: Branchiura).Parasitology.2004. 128:655–660.
9. T.A.Schram , L.Iversen, P.A.Heuch , E.Sterud. Argulus sp. (Crustacea: Brachiura) on cod, Gadus morhua from Finnmark, northern Norwaw. Journal of the Marine Biological Association of the UK.
2005. Vol. 85. P. 81–85.
10. C.V.Holland, C.R.Kennedy, 1997. A checklist of parasitic helminth and crustacean species recorded in freshwater fish from Ireland. Biol. Environ., 1997, 225-243.
11. D.W.Evans, M.A.Matthews, First record of argulus foliaceus on the euorpean eel in the British Isles.
Journal of Fsh Biology. 2000. Vol 57. P. 529-530.
12. P.D.Walker G.Flik , S.E.Wendelaar Bonga . The biology of parasites from the genus Argulus and a re- view of the interactions with its host. Symp. Soc. Exp. Biol. 2004 Vol. 55. P. 107–129.
13. G.W.Benz, Parasitic crustaceans: Back to basics. Reg. Conf. Proc., Amer. Zoo Aquar. Assoc., Wheeling. 1994. 76 – 83.
14. K.Yildiz and A. Kumantas. Argulus foliaceus infection in a goldfish (Carassius auratus ) . Vet. Med. j.
2002.Vol 57: (2) 1 – 5.
15. M.Bandilla, T.Hakalahti, P.J .Hudson and E.T Valtonen. Aggregation of Argulus coregoni (Crustacea:
Branchiura) on rainbow trout (Onchorhynchus mykiss): a consequence of host susceptibility or exposure? Parasitology 2005. 130, 169-176.
16. CNHP. Rapport annuel Maroc.1996.28p.
17. S.K.Rushton-Mellor,The genus Argulus (Crustacea:Branchiura) in Africa: identification keys. Syst Parasitol.1994, 28:51-63.
18. J.Paperna. Parasites, infections and diseases of fish in Africa – An update. CIFA Tech. Paper,1996.
31:p. 200 FAO, Rome, Italy.
19. I.E.Bykhovskaya-Pavlovskaya ., A.V.Gusev ., M.N.Dubinina , N.A.Izyumova .,T.S.Smirova ., I.L.
Sokolovskaya, 1962 Key To Parasites Freshwater Fishes of the USSR.
20. A.Oktener, A., A. Ali, A. Gustinelli, M. Fioravanti. . New host records for fish louse Argulus foliaceus L., 1758 (Crustacea, Branchiura) in Turkey. Ittiopatologia, 2006. 3: 161-167.
21. A.V.Pasternak, E. Mikheev Valtonen. Life history characteristics of Argulus foliaceus L. (Crustacea:
Branchiura) populations in Central Finland. Annales Zoologici Fennici, 2000. 37: 25-35.
22. E. Amlacher E. Textbook of fish diseases (Engl. Transl.). TFH Publ. Jerseycity. 1970,302.
23. A.B.Al-Zubaidy, Studies on the parasitic fauna of carps in Al-Furat fish farm Babylon province Iraq.
Ph D Thesis Coll Sci Univ Babylon. 1998,141.
24. Z.Kabata, Z. Copepoda (Crustacea) parasitic on fishes: problems and perspectives. Advances in parasitology.1981. 19, 1-71.
25. A.S.Grutter, Spatial and temporal variations of the ectoparasites of seven reef fish species from Lizard Island and Heron Island, Australia. Marine Ecology Progress Series. 1994. 115, 21–30.
26. L.Rozsa, Patterns in the abundance of avian lice (Phthiraptera: Amblycera, Ischnocera). Journal of Avian Biology.1997. 28: 249–254.
27. R.Poulin, R. Parasitism and Shoal Size in Juvenile Sticklebacks: Conflicting Selection Pressures from Different Ectoparasites. Ethology 1999.105, 959-968.
28. R.Poulin, R. and S. Morand. The diversity of parasites. Quarterly Review of Biology, 2000. 75, 277–
293.
29. C.S.Tucker, C.Sommerville, R.Wootten. The effect of temperature and salinity on the settlement and survival of copepodids of Lepeophtheirus salmonis (Krøyer, 1837) on Atlantic salmon, Salmo salar L. J Fish Dis.2000. 23:309–320.
30. A.M.Kuris, A.R.Blaustein, J .J.Alio. Hosts as islands. The American Naturalist, 1980.116: 570-586.
31. T.Pojmanska T, M.Chabros. Parasites of common carp and three introduced cyprinid fish in pond culture. Acta Parasitol.1993. 38: 101-118.
32. M.O.Öztürk,S. Bulut . An investigation on melazoan parasite fauna of common carp (C. Carpio L.) in Dam Lake Selevir. Sci. Eng. J. Firal üniv. 2006. Vol. 18 (2). P. 143–149.
33. P.D.Walker J.E.Haris , G.Van der Velde , S.E.Bonga Wendelaar. Effect of host weight on distribution of Argulus foliaceus (L.) (Crustacea, Branchiura) within a fish community. Acta Parasitologica. 2008.
Vol. 53 (2). P. 165–172.
34. A.I. Zafari, R. Mumtaz and R. Sajjad. Argulosis in some ornomental fishes imported to Lahore, Pakistan. European Journal of Veterinary Medicine, 2. 2013, No. 3, 171-178.
*Corresponding Author: Aba Mustapha; Biology and Health Laboratory, Environmental and Parasitology Team/UFR Doctoral, Sciences Faculty, Ibn Tofail University, Kénitra B.P. 133, 14000,
Morocco.
