The metazoan parasite fauna of the Indian mackerel Rastrelliger kanagurta of Visakhapatnam coast, Bay of Bengal comprised 15 species including three species of Monogenea, seven species of Digenea and five species of Crustacea. Digeneans were the dominant members in the parasite spectrum while infections with ectoparasitic monogeneans and crustaceans were rare. The digeneans Opechona bacillaris and Lecithocladium angustiovum which occurred with high prevalence and mean intensity are the typical parasites of the mackerel. The parasitic fauna in general is found to be a reflection of the planktonivorous diet of the host. Except for two species of digeneans, Lecithocladium angustiovum and Aponurus laguncula, all the remaining species of metazoans showed narrow specificity to R. kanagurta, indicating a high degree of host specialization. The parasitological data may prove useful for differentiating stocks of R. kanagurta.
One hundred and eighty four specimens of the mackerel Rastrelliger kanagurta collected from fish landings at Visakhapatnam coast, Bay of Bengal, between January 2006 and 2007, were examined for analysis of their metazoan parasite community structure at infra and component community levels and study the effects of season and host body length on these communities. Fifteen species of metazoan parasites were collected including 3 spp. Monogenea, 7 spp. Digenea and 5 spp. Copepoda. All the fish were parasitized by one or more metazoan parasite species. A total of 2,004 parasites were collected with a mean of 10.9. The majority were digeneans accounting for 42.4% of total number of parasites collected and the hemiurid Lecithocladium angustiovum is found to be the most dominant species. Mean values of species richness (3.0 ± 1.5), abundance (12.4 ± 9.3) and diversity (H 0 = 0.92) were within ranges observed for most of the metazoan parasite communities of marine fish from temperate and tropical countries. Seasonally, the mean diversity and parasite species richness of infracommunities were high during December and January and low during September-October. No correlation was found between host total length and any of the community descriptors. Most of the parasites i.e., 12 out of 15 species of parasites collected were host specialists. Only one species Aponurus laguncula was a host generalist. All taxa of metazoan parasites showed a typical over-dispersed pattern of distribution. The dominance of the core species in all the infracommunities and the high degree of host specialization of the parasite species resulted in the predictable component in the infracommunities to be high, each infra community comprising a core species accompanied by a few secondary species.
A new species of opecoelid trematode, Pseudopecoelus brayi sp. nov. is reported from the holocentrid fish, Myripristis kuntee collected from off Visakhapatnam coast, Bay of Bengal. The new species differs from related species by a combination of characters such as elongate body, deeply lobed gonads, tubular sinuous seminal vesicle extending up to the posterior border of ventral sucker, presence of a short cylindrical cirrus sac enclosing the cirrus and the vitelline zone extending anterior to ventral sucker. This is the 7th species of the genus to be reported from Indian marine fishes and the fifth species from holocentrid fishes. A key for separation of the species of Pseudopecoelus is given.
Sanguinicolids are blood flukes infecting marine and freshwater fishes in many parts of the world. Smith (1997a, 1997b) furnished a list of sanguinicolids reported to that date, together with their hosts and geographic distribution. Subsequently, many new genera and species of sanguinicolids were reported. According to the recent review of Smith (2002), the family contains 19 genera.
The monorchiid trematode Huridostomum formionis Mamaev, 1970 originally described from the black pomfret, Apolectus niger, from the Gulf of Tonkin by Mamaev (1970) is redescribed based on material collected from the same host from the Visakhapatnam coast, Bay of Bengal. The redescription provides additional information on the arrangement of the enlarged spines on the anterodorsal region of the oral sucker, the structure of the terminal genitalia and the course of uterus. The most significant features typical for the genus are considered to be the combination of morphological features including the presence of enlarged spines along the anterodorsal margin of the oral sucker, a very long elliptical cirrus sac, a unipartite terminal organ with the metraterm joining it distally, and extensive uterine coils. The genus Huridostomum is included in the subfamily Monorchiinae, its relationship with other monorchiid genera possessing spines anterodorsal to the oral sucker is discussed, and the validity of some of these genera is examined. Neopisthomonorchis Varma, 1982 is synonymized with Ametrodaptes Bravo-Hollis, 1956 and the new combination Ametrodaptes pristopomatis (Varma, 1982) n. comb. is suggested. Pseudametrodaptes n. gen. is erected to include the Indian species of the genus Ametrodaptes characterized by the absence of spines in the genital atrium and the presence of a unipartite terminal organ with the metraterm joining its distal end. The following new combinations are suggested: Pseudametrodaptes secundus (Madhavi, 1977) n. comb., Pseudametrodaptes bravoae (Ahmad, 1985) n. comb., Pseudametrodaptes caballeroi (Ahmad, 1985) n. comb. and Pseudametrodaptes fischthali (Ahmad & Dhar, 1987) n. comb.
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