Monogenean infestations in Thai silver barb (Barbodes gonionotus Bleeker) and their adaptations in Bangladesh waters

An investigation on the infestation of monogenetic trematodes of Barbodes gonionotus was conducted during the period from July '97 to June '98. Host specimens were collected from local fish farms and also from local fish markets of Mymensingh. Samples of P. ticto and P. sarana were also examined. Two species - Dactylogyrus lampam (Lim and Furtado 1986) and Dactylogyrus siamensis (Chinabut and Lim 1993) the Thai parasites were recorded from B. gonionotus and D. lampam, from our indigenous fish P. sarana. Two species of Gyrodactylus were also recorded from B. gonionotus. Both prevalence and intensity of infestation were moderate in B. gonionotus. Prevalences were recorded higher in larger fishes and mean intensity in intermediate size group fishes. Infestations were higher in winter months. Adaptations of the foreign parasites in Bangladesh waters, their transmission in local fishes and invasion of the local parasites to this exotic fish have been discussed. Suggestions have also been made to protect the introduction of new species in our waters.

Electrophoretic and immunotaxonomic studies of three species of marine gastropods from Portonovo coast with reference to population management

Electrophoretic and serological studies of foot muscle protein of three species of Cerithiacea (Telescopium telescopium, Cerithidea fluviatilis and C. obtusum) were carried out to understand their relationships. Living specimens were collected from mud flats and mangrove swamps off Portonovo. Polyacrylamide electrophoresis of proteins from foot muscle extract of T. telescopium, C. fluviatilis and C. obtusum showed that the former had a different densitometric profile as well as more number of protein bands; but the later two species showed a closer related pattern as well as lesser number of protein bands. At the same time these two species are distinguished from each other in their total number of bands and Rf values. Immunological studies using micro-Ouchterlony double diffusion tests which absorbed antiserum indicated that C. fluviatilis and C. obtusum were more closely related as revealed by an identity reactions than T. telesopium as shown by non-identity reactions. Results are discussed in relation to ecological and morphological adaptations