Observation on the urinogenital papilla and sexual dimorphism in some Indian gobiids (Gobiidae: Teleostei)

A thorough comparative study on the urinogenital papilla and sexual dimorphism has been made for the first time in both the sexes of twelve Indian gobiids: Glassogobius giuris (Hamilton); Acentrogobius cyanomos (Bleeker); Eleotriodes muralis (Valenciennes); Parapocryptes serperaster (Richardson); Apocryptes bato (Hamilton); Scartclaos viridis (Hamilton); Boleophthalmus boddarti (Pallas), Periophthalmus schlosseri (Pallas); P. koelreuteri (Pallas); Taenioides anguillaris (Linnaeus); T. buchanani (Day); Odontamblyopus rubicundus (Hamilton). The urinogenital papilla, originating as a free muscular organ from the ventral surface of the body-wall and shortly behind anus, is present in both the sexes. It is an important organ of primary sex recognition in all species. In case of male the papilla is conical, broad at the base and in female it is either flattened, distally truncated or bluntly rounded. The presence of permanent colour mark over the specific region of the body surface is another secondary sexual character in a few species. Besides, colouration may also be a nuptial secondary sex character developed in some during peak breeding season. The enlargement and colouration of the organ is subject to seasonal variations parallel to the seasonal gonadal cycle. The histological architecture of the papilla shows a high degree of cellular specialization and an interrelationship to the urinary and genital ducts. The functional efficacy and significance of the papilla in the breeding biology of these fishes has been discussed.

Experimental pathogenesis of Aeromonas hydrophila bacteria in shing Heteropneustes fossilis(Bloch)

Pathogenicity of Aeromonas hydrophila bacteria was tested on the stinging catfish Heteropneustes fossilis. Before artificial infection the morphological, biochemical and physiological characters of Aeromonas hydrophila were studied. The infections were done by two different methods, viz., intramuscular (IM) and intraperitoneal (IP) injection. In infection experiment, each group of 10 fish were injected either intramuscularly or intra peritoneally with one dose higher than the LD50 dose (9.6 x 107 CFU/fish). All the fish tested died within 1 to 9 days. Both in cases of intramuscular and intraperitoneal injection, external pathology were found. Haemorrhagic lesions were evident at the site of injection. The posterior end of the body surface was found to develop greyish-white lesion that was extended up to caudal fin. Hyperemic anal region and the fin bases were also observed. Total bacterial loads in liver, kidney and intestine were determined. Aeromonas hydrophila could be isolated from liver, kidney and intestine of the experimentally infected fish. In case of intramuscular injection the highest and the lowest bacterial load was found to be 2.4 x 107 CFU/g of liver and 2.1 x 102 CFU/g of kidney and in case of intraperitoneal injection they were found to be 3.6 x 106 CFU/g of kidney and 1.2 x 104 CFU/g of kidney respectively. It was concluded that A. hydrophila could cause serious disease condition to Heteropneustes fossilis and its pathogenesis in the fish was also very efficient.

Incidence of ulcer type of disease in wild fishes of Bangladesh

Disease occurred in wild fish species investigated in different water bodies like canals, ditches, beel, haor, flood plain in 17 districts of Dhaka division. Haemorrhagic lesions were observed on the body surface of affected fishes. Incidence of the disease in the investigated water bodies ranged from 0 to 100%. In total 19 fish species were found to be affected and prevalence of infection ranged from 0.0 to 100.0%. Channa punctatus and Puntius ticto were severely affected in all locations. Percentage of infection in these fishes ranged from 0.0 to 100.0. The highest infection was observed in Netrokona, Kishoreganj, and Mymensingh districts. Bacterial genera isolated from the lesions of these affected fishes were Aeromonas, Pseudomonas, Flavobacterium, Micrococcus, and Staphylococcus. Among these isolates Aeromonas was the dominant. Abundance of Aeromonas in the lesions among the investigated bacteria ranged from 75 to 90%. Five identified Aero monas lrydrophila were examined for their pathogenicity and were able to infect the experimental fish, silver barb (Puntius gonionotus). The pathogen Aeromonas hydrophila was thus considered to have an association with the outbreak of ulcer type of disease in the investigated fish species.

Studies on lipolytic bacteria in stored fish Etroplus suratensis (Bloch)

The distribution of total hectrotrophic bacteria (THB) and lipolytic bacteria in various regions (body surface, gill, intestine and flesh) of fish Etroplus suratensis (Bloch) during storage at 28 ± 2°C and 4°C was studied. Pseudomonas dominated at reduced temperature whereas at 28 ± 2°C and in fresh condition Vibrio, Aeromonas, and Acinetobacter dominated. Lipolytic activity was elaborated by the members of various genera and their activity varied in different lipid compounds (tributyrin, tween 80, tween 60, tween 40 and tween 20). Tributyrin was utilized by majority of the isolates. All the selected isolates preferred a temperature of 35°C and pH 6.0 for their maximum growth. Aeromonas and Vibrio showed maximum growth at 0.5% NaCl concentration while 3% NaCl was found to be optimum for Pseudomonas.

Plerchis heterorchis N. sp. (Digenea: Acanthocolpidae Luhe, 1909) from fishes Lutjanus johnii and Otolithus argenteus of Karachi coast, Pakistan

A new species of trematodes Pleorchis heterorchis is described from the fishes Lutjanus johnii and Otolithus argenteus of Karachi coast. The new species is characterized by having a lanceolate body with a notch at the middle of the posterior end of the body. Body surface is smooth, ventral sucker rounded, situated at the anterior middle region of the body, pre-pharynx is well developed, widened posteriorly, pharynx muscular, oesophagus short, intestine H-shaped with anterior arms much shorter than the posterior, intestinal bifurcation almost in the middle of fore body, anterior caeca wide and short extending as far as anterior limit of pharynx. Posteriorly caeca reach to posterior end of the body with no lateral out pocketing. Testes 44 in number, intercecal arranged in 2 parallel rows, sub-globular, entire to slightly irregular, almost of same sizes extending immediately from posterior of the ovary to anterior of excretory vesicle. Cirrus pouch overlaps the ventral sucker, extends into hind body, terminating above the ovary, containing bipartite seminal vesicle, pars prostatica and ejaculatory duct. Genital pore behind the intestinal bifurcation and pre-acetabular. Ovary pre-testicular, consists of 16 follicles of varying sizes. Vitellaria lateral, follicular, extending from post bifurcal to posterior extremity. Excretory vesicle reaches to the posterior level of last pair of testes.

The study of correlation between sea surface temperature (SST) by using the NOAA-AVHRR data and compare this data with temperature measurement in the Caspian Sea

The changes in time and location of surface temperature from a water body has an important effect on climate activities, marine biology, sea currents, salinity and other characteristics of the seas and lakes water. Traditional measurement of temperature is costly and time consumer due to its dispersion and instability. In recent years the use of satellite technology and remote sensing sciences for data acquiring and parameter and lysis of climatology and oceanography is well developed. In this research we used the NOAA’s Satellite images from its AVHRR system to compare the field surface temperature data with the satellite images information. Ten satellite images were used in this project. These images were calibrated with the field data at the exact time of satellite pass above the area. The result was a significant relation between surface temperatures from satellite data with the field work. As the relative error less than %40 between these two data is acceptable, therefore in our observation the maximum error is %21.2 that can be considered it as acceptable. In all stations the result of satellite measurements is usually less than field data that cores ponds with the global result too. As this sea has a vast latitude, therefore the different in the temperature is natural. But we know this factor is not the only cause for surface currents. The information of all satellites were images extracted by ERDAS software, and the “Surfer” software is used to plot the isotherm lines.