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Aquatic Commons (31,125 recursos)
The Aquatic Commons is a thematic digital repository covering the natural marine, estuarine /brackish and fresh water environments . It includes all aspects of the science, technology, management and conservation of these environments, their organisms and resources, and the economic, sociological and legal aspects.

Subject = Biology

Mostrando recursos 1 - 20 de 4,868

1. A study on the lipid distribution pattern in muscles of two teleosts, Arius dussumieri and Ophiocephalus striatus - Alexander, K.M.
The muscles of the various regions and zones of the body of the two teleosts, A. dussumieri and O. striatus have been analyzed for lipid contents. There is a significant dorsum-ventral gradient in lipid concentration exhibited by both the fishes with higher lipid values in the ventral aspect of the body, especially the belly flaps. As regards the vertical series, both the fishes exhibit comparatively higher lipid contents at the dorsal aspects of the caudal region and at anterior portion of the dorsal fin area with lower lipid values at cephalic and middle portions of the body. The red muscle...

2. Estudio biológico pesquero del langostino de Mar del Plata en conexión con la operación nivel medio. - Angelescu, V.A.; Boschi, E. E.

3. Distribution of Macrobrachium rosenbergii (de Man) in three rivers of Paikgacha, Bangladesh - Khair, S.A.; Hossain, M.A.; Parween, S.
Distribution of post larvae, juveniles and adults of Macrobrachium rosenbergii was studied in three rivers of Paikgachha, Khulna during November '91 to Apri1 '94. The adults were found to ascend upstream and the matured ones again return to the estuary to breed. Post larvae of M. rosenbergii prefer a salinity range in between 0.5 to 19.0 ppt and juveniles require a salinity range in between 0.0 to 2.0 ppt.

4. Acute toxicity of chlorpyrifos, cadusafos and diazinon to three Indian major carps (Catla catla, Labeo rohita and Cirrhinus mrigala) fingerlings - Hossain, Z.; Haldar, G.C.; Mollah, M.F.A.
Fingerlings of three Indian major carps, viz. Catla catla (Hamilton-Buchanon), Labeo rohita (Hamilton-Buchanon) and Cirrhinus mrigala (Hamilton-Buchanon), were exposed to different concentrations of chlorpyrifos (lorsban 10 G), cadusafos (rugby 10 G) and diazinon (basudin 10 G) for a period of 96h with a view to determine the median lethal concentrations (LC sub50) values for each of chemicals. Of the tested concentrations, chlorpyrifos at a dose of 6.65 ppm, cadusafos at 2.0 ppm and diazinon at a dose of 8.40 ppm or above induced 100% mortalities within 96h of exposure. The 96h LC sub50 values of chlorpyrefos, cadusafos and diazinon were...

5. A histological study of the spermatogenesis in Ompok pabda (Hamilton-Buchanan 1822) - Siddiqua, K.A.; Islam, M.S.; Hussain, M.G.; Ahmed, A.T.A.
The present study deals with the histological analysis of testicular development in Ompok pabda. For the study, male gonads were collected month wise from January to September at Freshwater Station, BFRI, Mymensingh. From the analysis, 4 stages of sperm formation, namely, spermatogonia, spermatocytes, spermatids and spermatozoa, were distinguished. The percent distribution of spermatozoa was highest in July (about 92%). Maximum GSI value was 1.129±0.271 found in July. By analyzing the histology of spermatogenesis it was established that this species breeds once in a year.

6. Population dynamics of the ribbon fish, Lepturacanthus savala (Cuvier 1829) from the north-eastern part of the Bay of Bengal - Mustafa, M.G.; Zafar, M.; Haque, M.A.; Amin, S.M.N.
Population parameters of Lepturacanthus savala from the trawl catches in the north-eastern part of the Bay of Bengal, Bangladesh were investigated based on length frequency data, using complete ELEFAN computer program. The asymptotic length (Lα) and growth constant (K) were estimated to be 106.50 cm (total length) and 0.80/year respectively. Based on these growth parameters, the total mortality (Z) was estimated to be 1.89. The estimated values for natural mortality (M) and fishing mortality (F) were 1.08 and 0.81 respectively. The estimated value for the exploitation rate (E) using the length converted catch curve was 0.43. The recruitment pattern showed...

7. Pathology of mixed infections of saprolegniasis-myxosporidiosis in Indian major carp (Catla catla Ham.) - Sahoo, P.K.; Mukherjee, S.C.; Nayak, S.K.; Dey, S.
An outbreak of saprolegniasis in Catla catla in composite carp culture ponds were recorded during winter season. The typical cotton wool growths were observed on whole body surfaces of catla along with sporadic mortality. The fungal invasion was only restricted to skin and no fungal elements were visible in any internal organs after periodic acid schiff staining. On histology, periportal accumulation of mononuclear cells in liver, presence of myxosporidean cysts in antieror kidney, eosinophilic granular cells reaction in submucosa of stomach and intestine, dilated and engorged blood vessels of brain along with sloughing of epidermis and hyperplasia at gill lamellar...

8. Pathogenicity of Aeromonas sobria to Thai silver barb (Barbodes gonionotus Bleeker) and its sensitivity to some antibiotic agents - Sarker, M.A.; Uddin, M.N.; Sarker, M.G.A.; Chowdhury, M.B.R.
Five isolates of Aeromonas sobria, collected from the diseased fish were selected for detection the pathogenicity following water-born infection method on silver barbs (Barbodes gonionotus) at the selected exposure dose 2.5x10⁸ CFU/ml which was standardized by preliminary test. In the experimental condition lesion and mortality were found in fishes. Among the isolate, Ass17 Ass19, Ass31 and Ass36 were successfully infected 20-60% fishes. Another isolate Ass20 was found non-pathogenic. Drug sensitivity test was performed by six antibiotics viz. Oxytetracycline, Oxolinic acid, Chloramphenicol, Stilphamethozazole, Streptomycin, Erythromycin. All the isolates showed variable reaction patterns to antibiotics. Most of the isolates were found sensitive...

9. Larval development of a mangrove crab (Perisesarma bidens De Haan) (Crustacea: Brachyura: Sesarminae) - Islam, M.S.; Shokita, S.
Larval development of Perisesarma bidens (De Haan) was investigated in laboratory conditions. Morphology of all larval stages and 1st crab stage was described and illustrated in detail, and compared with other species of sesarmid crabs. The zoeae morphological features of P. bidens are almost similar to other species of Sesarma in lacking a pair of lateral spines on carapace.

10. Binding of radio-iodinated gonadotropin to the ovary of exotic carp (Cyprinus carpio Lin.) - Chakraborty, B.; Bhattacharya, S.
Heterologous murrel gonadotropic hormone (m-GtH) binds to common carp oocyte plasma membrane and enhances steroid secretion. With increasing concentration of radio-labelled hormone the receptor binding is also found to increase linearly up to a certain concentration and then decrease. The [¹²⁵I] murrel GtH binding characteristics to a preparation of common carp ovarian plasma membrane shows saturability with high affinity. Scat chard plot analysis gave dissociation constant (Kd) of 0.81 X 10(super -9) M and maximum binding capacity (MBC) of 22.05 f mole/mg protein.

11. Histological distribution and ultrastructure of exocrine pancreas in Indian major carp (Labeo rohita Ham.) and its alteration in aflatoxicosis - Sahoo, P.K.; Mukherjee, S.C.
The distribution pattern of exocrine pancreas in Labeo rohita besides its general location along the course of intestinal mesentery was studied. It is evenly distributed within the liver around portal vessels and also within the spleen near a blood vessel. On ultrastructure, two cell types of different degrees of staining intensities containing abundant rough endoplasmic reticulum, mitochondria, pre-zymogen and zymogen granules were marked. During aflatoxicosis, the mesenteric pancreas and hepatic pancreas were mostly affected revealing necrotic changes to acini. The zymogen granular activities were markedly reduced. Ultra structurally, the rough endoplasmic reticulum was fully dilated and formed whorled pattern. The...

12. Studies on the gonadosomatic index and fecundity of chapila (Gudusia chapra Ham.) - Kabir, A.K.M.A.; Hossain, M.A.; Rahmatullah, S.M.; Dewan, S.; Islam, M.S.
The study was conducted in pond to determine the fecundity and gonadosomatic index of chapila, Gudusia chapra. The male fish was found to attain sexual maturity at 7.7 cm and 7.41 g and that of the female at 9.3 cm and 14.65 g by standard-length and body-weight respectively. The investigated fishes were found to be male and female at the ratio of 1:3 and generally female was found to be larger than male. The fish was found to spawn for several months with two spawning peaks, one in April and another in August as indicated by the peaks of gonadosomatic...

13. Rearing of catfish (Clarias batrachus Lin.) larvae with live and prepared feeds - Yasmin, A.; Mollah, M.F.A.; Haylor, G.S.
Provision or live feed (Tubificid worms) attributed significantly better weight gain in the five days old Clarias batrachus larvae when reared for another 28 days compared to those fed mixed feed (live and artificial) and artificial feed only. Larvae fed mixed feed showed significantly better weight gain compared to those fed only artificial feed and the survival rate was similar to those fed only live feed. Both the weight gain and survival rate were the lowest for the larvae reared only on artificial feed.

14. Predatory behaviour of a snakehead fish (Channa striatus Bloch) - Das, M.; Chakraborty, S.C.; Ahmed, F.; Basak, R.K.
The predatory behaviour of a snake-head, Channa striatus (Bloch) on Labeo rohita fingerlings was studied in the laboratory. The study was conducted with six C. striatus (120 to 210 g and 22 to 28 cm) over 24h a day for 3 weeks. Three different sizes prey of large (2.00g and 5.8cm), medium (1.30g and 4.5cm) and small (0.72g and 3.5cm) were used for the first week and then medium size prey for 2nd and 3rd weeks. All the predators preferred eating the small group of L. rohita although all three size groups of L. rohita offered were available. It was...

15. Some aspects of association and development of Lytocestus indicus Moghe in catfish Clarias batrachus (Lin.) - Chandra, K.J.; Islam, K.Z.; Wootten, R.
Some aspects of association and development of the caryophyllid cestode Lytocestus indicus Moghe, 1925 infecting the catfish Clarias batrachus (Linn.) from the Kailla Beel of Mymensingh, Bangladesh were studied. About 33.14% of Clarias batrachus were infected with a mean intensity of 3.75, mean density 1.25. The infection was not found throughout the year. Two seasonal occurrence of this cestode were observed, one in April-May and the other in August-September. However, maturation period of the worm coincided with the maturation of the host. The worm was found attached to the wall of the intestine of the host. At the site of...

16. Induction of mitotic and meiotic gynogenesis and production of genetic clones in rohu, Labeo rohita Ham. - Hussain, M.G.; Mahata, S.C.; Rahman, M.S.; Tanu, M.B.; Mazid, M.A.; Islam, M.S.
Studies were undertaken to produce genetic clones derived from all homozygous mitotic gynogenetic individuals in rohu, Labeo rohita Ham. ln view of this, attempts were made to interfere with the normal functioning of the spindle apparatus during the first mitotic cell division of developing eggs using heat shocks, there by leading to the induction of mitotic gynogenetic diploids in the F1 generation. Afterwards, viable mitotic gynogenetic alevins were reared and a selected mature female fish was used to obtain ovulated eggs which were fertilized later with UV-irradiated milt. Milt was diluted with Cortland’s solution and the sperm concentration was maintained...

17. Digestible protein and energy value of fish meal, dextrin, fish oil and soybean oil for Thai sharpunti (Puntius gonionotus Bleeker) - Hossain, M.A.; Rahman, M.M.; Chakraborty, S.C.
A laboratory trial was conducted to determine the digestible protein and energy value of fish meal, dextrin, fish oil and soybean oil for Thai sharpunti (Puntius gonionotus Bleeker). A reference diet containing 35% protein was formulated in which fish meal was the sole source of protein. Five test diets were formulated using reference diet and individual test ingredients (fish meal, dextrin, fish oil and soybean oil). Each treatment had three replicates with 15 fish per replicate. Fish were fed twice daily at the rate of 5% of their body weight. The result of the study indicated that the dietary protein...

18. Effect of stocking density on growth of tiger shrimp (Penaeus monodon Fab.) fed on commercial formulated diets - Chakraborty, S.C.; Paul, A.K.; Hossain, M.A.
Three different stocking rates in a semi-intensive pilot shrimp project was adopted in duplicates of three treatments designated as T1, T2 and T3 having initial per meter square stocking density of shrimp of 40, 44 and 51 respectively of 0.025g size post larva. The study was conducted for 84 days. Commercial pelleted diets designated as starter - 1, 2, 3 and grower were fed at a satiation level during the study period with a feeding frequency of 4 to 5 times per day. Feed rationing was based on the survivability, body weight and tray checking. 5-25% of the pond water...

19. Impact of stocking density on growth and survival rate of mud crab (Scylla serrata Froskal) - Rani Saha, M.; Roy, P.K.; Ahmed, S.U.
A 10-weeks culture trial of mud crab, Scylla serrata in brackish water earthen pond was conducted in different stocking densities. The aim of the experiment was to identify a suitable stocking density for optimum production. There were three treatment as 5000 crab lings/ha, 10000 crab lings/ha and 15000 crab lings/ha of each with three replications. The initial mean weight of crab lings were same (5.5 ± 0.13 g). The experimental month was June '95 to August '95. The size of each pond was 500 m². To maintain good water quality water was exchanged in every spring tide. The salinity during...

20. A study on damage caused to crustacean and finfish larvae during collection of Penaeus monodon (Fab.) postlarvae in the estuaries of Barguna, Bangladesh - Rahman, S.L.; Islam, M.M.; Hoq, M.E.; Haldar, G.C.; Ahmed, S.U.
A year round investigation in the estuaries of Barguna district revealed that for each Penaeus monodon postlarvae (PL), about 37 larvae of other shrimp species, 12 finfishes and 10 macrozooplankters are destroyed during the process of shrimp seed collection. Although abundance of P. monodon PL was not recorded throughout the year, a significant number of other shrimp spp., fin fishes including macrozooplankters are being damaged by the shrimp seed collectors. This indiscriminate destruction of aquatic organisms during P. monodon PL collection is serious threat to aquatic biodiversity.

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