Research Journal of Parasitology

Year: 2010 | Volume: 5 | Issue: 3 | Page No.: 148-155
DOI: 10.17311/jp.2010.148.155

Survey on the Digenean and Monogenean Helminthes of Clupeidae (Teleostes) from Southern Part of Caspian Sea

H. Varshoie, I. Mobedi, M. Aghazadeh Meshgi and B. Jalali

Abstract: The helminthes parasites fauna of 313 specimens of Caspian herrings (Clupeonella cultriventris, Clupeonella engrauliformis, Clupeonella grimmi) caught from catching localities situated in southeast of Caspian Sea Were investigated during winter 2008 until autumn 2009. A total of 3 helminthes species were found. They were including Pseudopentagramma symmetrica from intestine (mid gut, hind gut and cecae) Bunocotyle cingulata in intestine, Mazocreas alosae the only monogenean with Marine origin in the gills of infected specimens. In addition to two zoonotic species including Contracecum sp. and Anisakis sp. in digestive system, muscle and ovary and an Acanthocephal, Corynosoma strumosum in intestine which were previously reported. We can conclude that the main characteristic of the helminthes parasites community of Clupeidae species studied is the dominance of the endoparasites species due mainly to the digenean Pseudopentagramma symmetrica and Bunocotyle cingulata and the relative scarcity of ectohelminthes fauna. In this paper the latest data of helminthes fauna and community ecology of digenean of Clupeidae species are presented and the community structure of Pseudopentagramma symmetrica is discussed.

Keywords: Clupeidae, Iran, digenean, monogenean, South of Caspian Sea and ecology

INTRODUCTION

Members of Clupeidae family are present in all seas and oceans, some always live in freshwater while most species inhabits in sea or brackish water, a relatively small numbers are anadroumous and enter to freshwater for propagation porpose. Genus Clupea is found in black and Caspian seas basins with 5 species, 3 of which are living in the Caspian Sea and Iranian waters (Clupeonella cultriventris, Clupeonella engrauliformis, Clupeonella grimmi). Among them, however, C. engrauliformis is mainly live in Northern and central part of Caspian Sea and does not enter freshwater. While two other species migrate between the two environment.

Clupeonella sp. are economic fish species in Caspian Sea either as an important food fish for valuable sturgeon, sander, Caspian foca and Caspian salmon or as human food. Plankton is the main food and copepods predominate but diet also includes Cladocera, Balanus and clam larvae (Berg, 1964). The most intensive feeding is in summer and autumn decreasing in winter and during reproduction in C. cultriventris (kilka-ye-maamoli or common kilka). In C. engrauliformis (anchovy kilka) the dominant food item is the copepod Eurytemora grimmi particularly in winter when plankton biomass is lowered (Abdoli and Naderi, 2009). While in Clupeonella grimmi (kilka-ye-cheshmdorosht or big eye kilka) migratory Mysides often predominate in planktonic diet of this species, fish fry are also eaten (Abdoli and Naderi, 2009).

These three Clupeonella share the available habitat and its foods: Common kilka in shallow, coastal waters, the anchovy kilka in the upper layers of the open sea and the big eye kilka in the deeper water of the open sea. During 1999-2004 years’ sudden depletion of Clupeids stock happened from 85000 to 7500 ton in south part of Caspian sea (Esmaili Sari et al., 2001). The first report on the parasite fauna of Clupea sp. in Caspian Sea was appeared by Dogielov and Bychowsky (1983). After a neglectful period, Shamsi et al. (1998) reported the degenian parasites Pseudopentagramma symmetrica and Bunocotyle cingulata, the Acanthocephal Corynosoma strumosum, Metacercaria of a Bucephalus sp., larvae of Contracecum and Anisakis species in all three Clupeids species in samples caught from Babolsar and Bandar-e-anzali catching sites. This study provides the recent data on prevalence, intensity of digenean and community of helminthes of three Clupeids species in the south of Caspian Sea with emphasis to population structure of P. symmetrica and B. cingulata in Clupeids in Caspian Sea.

MATERIALS AND METHODS

Three Clupeonella species (Clupeonella engrauliformis, Clupeonella cultriventris and Clupeonella grimmi) were subjected for helminthology examination during winter 2008 until autumn 2009 (Fig. 2a-c).

Samples were taken from catching site Babol-sar (52-39-30 longitude and 36-43 latitude) and Bandar-e-anzali (49-28-longitude and 37-28-latitude) both situated in south part of Caspian Sea (Fig. 1). Samples were first bioexamined and then helminthological investigations were carried out as follows:

Monogenea
Fish gills were cut out and examined under a stereomicroscope at x4-40 magnification. Vigorously moving worms were separated from the gills with a pipette and fixed under a cover slip according to Fernando et al. (1972) and Gussev (1983) either in ammonium picrate or glycoral-gelatine.

Digenean
Adult’s digenean were recovered from different part of intestine and collected in a 0.6% saline solution. The sample was placed with a little saline on a glass slide and appropriate pressure applied. It was fixed with 90% ethyl alcohol and was held in 70% ethyl alcohol and finally stained with alum haematoxylin according to Fernando et al. (1972) and Roberts (2001).

Identification of fishes were carried out by Iranian ichthyologist according to Abdoli (1999). The identification of parasites was carried out in accordance with the keys given by Gussev (1985, 1987) and Jalali (1998).

RESULTS AND DISCUSSION

During winter 2008 until autumn 2009 total 313 fish specimens of three Clupeids species inhabits in southern part of Caspian Sea were collected for helminthological purposes. According to our results these were composed 3 helminthes from intestine and gills which identified to species level. These finding and those which reported by Shamsi et al. (1998) are shown in Table 1. In total 181 specimens (57.82%) including 47.52% male and 52.48% female were infected by gill and intestine helminthes. Among them, however, P. symmetrica was regarded as a major helmenthes in the Clupeid fish with 53.1, 50 and 58.8% prevalence in C. cultriventris, C. grimmi and C. engrauliformis respectively. It should be taken into consideration, that in spite of examination of 313 specimens of 3 Clupeids in the present survey, two zoonotic species including Contracecum and Anisakis in digestive system, muscle, ovary and Acanthocephal, Corynosoma strumosum in intestine of infected Clupeids which were previously reported by Shamsi et al. (1998), were absent in our examined specimens (Table 2). In same table prevalence of B. cingulata in Babolsar catching site is also presented. In Table 3, prevalence of helminthes in Clupeids in different seasons of the study year in southern part of the Caspian sea are shown.

In Table 4, measurements of P. symmetrica and B. cingulata from respective hosts and locality:

Pseudopentagramma symmetrica (Chulkova, 1939) (Fig. 4)

Bunocotyle cingulata (Odhner, 1928) (Fig. 3)

The main characteristic of helminthes community of Clupeids studied is the dominance of the endohelminthes species and individuals, due mainly to the digenean P. symmetrica and the relative scarcity of ectohelminthes fauna, it is interesting to note that except ectoparasite Mazocreas alosae and endoparasite P. symmetrica which specific to Clupeidae fish family and distributed in all of the world (Gussev, 1985, 1987), other 4 helminthes parasites species reported herein and by Shamsi et al. (1998) are generalist, explaining their occurrence in other fish hosts of elsewhere also.

For instance, genera Contracecum and Anisakis larvae occurred in various Cyprinid, Percid, Esocid and Clupeid fishes in encysted in flat or rounded capsulate in the serosa of different organ, mesentery or musculature of hosts (Moravec, 1994).

In the present study, prevalence and intensity of infection by P. symmetrica in three Clupeid species was taken to consideration. According to our finding prevalence of infection by P. symmetrica in C. engrauliformis was 58.8%, in C. cultriventris was 53.1% and in C. grimmi was 50% which was lower than two other fish species (Table 2). In contrary, the intensity of infection log P. symmetrica in C. cultriventris varying from 2 to 350 (mean of 26) where as in C. grimmi varying from 5 to 32 (mean of 19.4) and in C. engrauliformis varying from 7 to 30 (mean of 15.8) (Table 5).

The highest number of P. symmetrica counted in C. cultriventris was 350. In total 3900 parasites specimens were collected from in 150 C. cultriventris specimens while, the no of parasites specimens in C. grimmi counted 135.8 and for C. engrauliformis 158 parasites specimens. As mentioned be for, lack of zoonotic nematodes larvae and Acanthocephal species in the present study may be interpreted due to both chemical and biological environmental alteration of Caspian sea between two different period of study (Shamsi et al., 1998; Present Survey, 2009) which has not yet fully understood, although the chemical pollutions are suggested the main accuser.

Such environmental alteration in Caspian Sea which caused unexpected depletion of Clupeids stocks {sudden depletion of Clupeids stock from 85000 to 7500 ton in south part of Caspian sea (Esmaili Sari et al., 2001)} or sudden increasing population of Jellyfish (Cnidaria) Mnemiopsis leidyi (Agassiz, 1865) (Esmaili Sari et al., 1999) are good examples of the results of such ecological changes.

In conclusion, Helminthes species composition and species richness of digenean in clupeid fishes in south of Caspian sea appear to vary significantly from time to time, particularly on the species of genera Contracecum and Anisakis which can adversely affects public health when ingested, therefore permanent monitoring of infection of Clupeids and continues researches on uncontrolled entry of chemical pollutions due to agricultural and industrial development activities are strongly recommended.

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