Dr. Murai Éva szerk.: Parasitologia Hungarica 22. (Budapest, 1989)
Agapova, 1956 and renamed it Molnárja leiicisci. MORA VEC (1982) synonimized G. amuri with the species Sinoichthyonema ctenopharyngodoni Wu, 1973, renaming the species Sino ichthyonema amuri (Garkavi, 1972). MATERIALS AND METHODS The study was conduced between November 198« and February 1989. The age and place of origin of the grasscarp examined were as follow: 1, Three 3-year old grasscarp from the dead arm of River Körös. 2. Ten 3- to 4-year old grasscarp submitted for laboratory examination from fish louse infested farm ponds of a fish farm situated between the Rivers Danube and Tisza. 3. The inner organs of 60 3- to 4-year old grasscarp of unknown origin and processed for meat. 4. Sixty grasscarp fry and 2-year-old grasscarp from different farm-ponds. The swimmbladder and the mesentery off the Intestine and kidney were placed in 0.65% saline. Actively moving helminths were looked for by gradually tearing the serosa to pieces. The collected helminths were placed under a coverslip either alive or after fixation in 70% ethanol and were cleared in lactophenol solution. RESULTS Specimens of the helminth species Sinoichthyonema amuri (Garkavi, 1972) and Skrjabillanus schigini Tikhomirova et Rudometova, 1975 were found in all 3 and 10 fish obtained from the Dead Körös and from the territory east of the River Danube respectively. About 10 to 15 specimens of both S. amuri and S. schigini were found in each fish. In most cases the specimens of S. amuri occurred freely on the abdominal and perirenal serous membranes, while those of S. schigini , showing multiple coils, were released from the mesentery connecting the two swimbladder sacs with the intestines. Only 4 out of the 60 grasscarp processed for meat were parasitized by 1 to 4 specimens of S. amuri and S. schigini . No helminths were found in grasscarp fry and 2-year old grasscarp. Male and female nematodes occurred in the same number in the test material. Their measurements corresponded to those reported by BAUER et al. (1987). The males were much smaller than the females. Morphologically S. amuri (Fig. 1/a, b,c) did not differ from drawings published by LOMACHIN and TSCHERNOVA (1980). However, both the buccal apparatus and the male copulatory organs (Fig.?Va, b) of S. schigini differed from those depicted on drawings published by TTKHOMTROVA and RUDOMETOVA (1975) and were much more similar to those of S. amuri. DISCUSSION The present study shows that the specific grasscarp parasites S. amuri and S. schigini are common in fish older than two years. The high prevalence of infection in the stock infested by fish louse can be explained by the development of skrjabillanids. Namely, from the studLegend to the figures: Fig. 1. Anterior and posterior end of Sinoichthyonema amuri, (a) Anterior end with sclerotinized buccal capsule, (b) Posterior end in lateral view, (c) Posterior end from above, x 500 Fig. 2. Anterior and posterior end of Skrjabillanus schigini. (a) Anterior end. (b) Posterior end. x 500 (Authors photo.)
