Determination of population structure and stock composition of chum salmon (Oncorhynchus keta) in Russia determined with microsatellites

Variation at 14 microsatellite loci was examined in 34 chum salmon (Oncorhynchus keta) populations from Russia and evaluated for its use in the determination of population structure and stock composition in simulated mixed-stock fishery samples. The genetic differentiation index (Fst) over all populations and loci was 0.017, and individual locus values ranged from 0.003 to 0.054. Regional population structure was observed, and populations from Primorye, Sakhalin Island, and northeast Russia were the most distinct. Microsatellite variation provided evidence of a more fine-scale population structure than those that had previously been demonstrated with other genetic-based markers. Analysis of simulated mixed-stock samples indicated that accurate and precise regional estimates of stock composition were produced when the microsatellites were used to estimate stock compositions. Microsatellites can be used to determine stock composition in geographically separate Russian coastal chum salmon fisheries and provide a greater resolution of stock composition and population structure than that previously provided with other techniques.

Quantitative determination of the timing of otolith ring formation from marginal increments in four marine teleost species from northwestern Australia

The sectioned otoliths of four fish species from a tropical demersal trawl fishery in Western Australia revealed a series of alternating trans-lucent and opaque zones in reflected light. The translucent zones, referred to as growth rings, were counted to determine fish ages. The width of the opaque zone on the periphery of the otolith section as a proportion of the width of the previous opaque zone (index of completion) was used to determine the periodicity of growth-ring formation. This article describes a method for modeling changes in the index of ring completion over time, from which a parameter for the most probable time of growth-ring formation (with confidence intervals) can be determined. The parameter estimate for the timing of new growth-ring formation for Lethrinus sp. 3 was from mid July to mid September, for Lutjanus vitta from early July to the end of August, for Nemipterus furcosus from mid July to late September, and for Lutjanus sebae from mid July to mid November. The confidence intervals for the timing of formation of growth rings was variable between species, being smallest for L. vitta, and variable between fish of the same species with different numbers of growth rings. The stock assessments of these commercially important species relies on aging information for all the age classes used in the assessment. This study demonstrated that growth rings on sectioned otoliths were laid down annually, irrespective of the number of growth rings, and also demonstrated that the timing of ring formation for these tropical species can be determined quantitatively (with confidence intervals.

Effect of different media on the determination of the number of micro organisms in frozen prawns (shrimp)

The Indian standards Institution have recently laid down specifications for the grading of frozen shrimp of which the bacterial examination of the product forms a significant part. Work carried out in this regard in our laboratories have shown that various improvements could be made in the composition of the medium to obtain a more true picture of the total bacterial count. Changes in the medium for total bacterial count have, therefore, been suggested and the reasons for the same discussed.

Determination of ubiquinone and tocopherol in heart, liver and muscle tissues of fresh water fish, Rohu (Labeo rohita, Hamilton)

The liver, heart and muscle tissues of Rohu, (Labeo rohita, Hamilton) were examined for their ubiquinone (UQ) and tocopherol contents. These three tissues contained respectively 11.60, 3.94 and 0.19 mg of ubiquinone and 10.16, 5.32 and 3.58 mg of tocopherol per 100 g. The 4% (V/V) of diethyl ether (EE) in light petroleum ether (PE) fractions of all three tissues on paper chromatographic separation gave spots having the same Rf value as standard ubiquinone-50 (UQ 10). Both the 4% and 6% (V/V) diethyl ether in light petroleum ether fraction of liver, heart and muscle tissues gave a single spot with the same Rf value as α – tocopherol.

Determination of length-weight relationship of squid (Loligo duvauceli) found along Pakistan coast

Common squid (Loligo duvauceli) is caught as by-catch of shrimp trawlers in shallow coastal. waters off Pakistan. Size frequency data of squid for sexes combined collected from Karachi Fish Harbour were analyzed. The length-weight relationship of the form W = a.L b was determined and to mean length of squid sample measured compared with mean length derived from inverse equation was tested for any significant differences, none were observed and it was inferred that the equation W = 0.243xL 2.2424 describe the relationship.

Determination of length-weight relationship in Sepia pharaonis and test for sex specific variation

The parameters a and b of the length-weight relationship of Sepia pharaonis of the form of W=a.L was determined. Sex separated size fequency data collected from Karachi fish Harbour was analysed the length-weight equations, separable by male, female and sex combined. The apparent difference in paired values of exponents b1, b2 for any combination i.e. male versus female and male, female versus sex combined was tested for their significant difference. No significant difference was observed for any combination, this indicated no sex specific variation in length-weigh relationship of Sepia pharaonis.

Determination of threshold current densities for different reactions of fishes using a pantostat

The threshold current densities required for first reaction, galvanotaxis and galvanonarcosis of fish depended upon species, length of the body, conductivity of water, nature of current and frequency of impulses. The threshold values and their ratios decreased with increase in length of fish. With rise in conductivity of water in the ratio of 1:4:13, these values increased in the ratio 1: 2:5. Impulse D. C was superior to continuous D. C and the threshold values of current densities for different reactions of fish decreased with rise in impulse frequency reaching minimum at an impulse frequency of 48/sec. Among Salmo irideus, ldus melanotus and Cyprinus carpio, the first one was affected earlier and required minimum current densities to exhibit the reactions, while the last one showed similar reactions only at higher current densities.

Determination of acute mercury toxicity to developing stages of Cyprinus carpio and Cirrhinus mrigala

Toxicity of inorganic mercury to different life history stages of fresh water fishes, Cyprinus carpio and Cirrhinus mrigala were demonstrated by static bioassays. 48 and 94% of egg hatching occurred in controls at 72 and 24h of experimentation in C. carpio and C. mrigala respectively. While fish eggs in water containing mercuric chloride showed delayed development as compared to the control. LC50, LC100 and safe concentrations of hatchling, fry and fingerling were calculated. Hatchling and fry were observed to be more susceptible as compared to fingerlings of C. carpio and C. mrigala.

Milt quality determination of a critically endangered fish, olive barb (Puntius sarana, Ham.) in Bangladesh

The present study was aimed to evaluate the characteristics of the olive barb sperm. Milt was collected fortnightly from 49 male fish (mean weight 90.8 g and length 18.64 cm) from April to July in 2008. In the olive barb ejaculated milt, volume (µl/g), motility (%), duration of motility (s), concentration (x 10 super(10)/ml) and pH values were found to be 6.06±0.32, 88.27±0.71, 171.41±7.41, 5.16±0.05 and 7.75±0.04, respectively. Milt volume was significantly (P<0.05) correlated with sperm concentration. Milt volume, sperm concentration, motility and duration of motility significantly varied (P<0.05) during spawning season.

The survey on determination of malathion biomarker with genotoxicity and ecophysiological reactions in the Caspian roach (Rutilus rutilus caspicus)

In the present study possibility of Malathion biomarker with Genotoxicity and Ecophysiological reactions were determined in Caspian Roach (Rutilus rutilus caspicus). At fist LC50 value of Malathion, an organophosphate insecticide was determined. Then four groups of experimental fish (containing 30 fish in each group) were exposed to different concentrations of Malathion. e. 0, 0.01, 0.05 and 0/1 ppm respectively for 23 days and effects of Malathion on Hematological (RBC, WBC, Hb and Hct) and biochemical parameters (Glucose, triglyceride, urea, total protein and Albumin), some enzymes (SGPT, SGOT and ALP), Cortisol level, plasma cations (Na+ and K+) , histological changes (gill and liver) and finally DNA destruction were examined. Sampling was done in 3rd, 13th, 23rd days during exposure and also 30 days after recovery. Data analysis was done by SPSS (Ver.13) and graphs were drawn by Excel 2007. Results showed that WBC, RBC, Hb, Hct, some biochemical parameters and K+ of Mallation treatments were decreased significantly in compare to control group (P<0.05). Changes in enzyme were many different. No significant changes were observed in Na+ and cortisol levels (except in groups treated with 0.01 Mallation) (P>0.05). LC50 value of Malathion in Caspian Roach was 6.5 ppm. Histological examinations showed that Mallation cause tissue damages and there were more damages in longer times and in higher concentrations. Apoptotic cell and comet were observed as DNA destruction and they were more in treatments with higher Mallation concentrations for longer times.

Determination of bioaccumulation and microscopic survey of LAS pollutant effect on the liver, kidney and gill tissues of Rutilus frisii kutum in Caspian sea

Linear alkylbenzene sulfonate (LAS) are widely used in detergent industry. Due to contaminants entering the water, and the effects of their accumulation in fish, LAS, has a great importance in environmental pollution. In the present study, accumulation of LAS and its histological effects on gill tissue, liver and kidney of Caspian kutum (Rutilus frisii kutum) were studied. Caspian kutum is the most important and most valuable teleosts of the Caspian Sea. Due to releasing Caspian Kutum in rivers and Anzali Lagoon and unlimited entry of wastewater to the aquatic ecosystem, research on the impact of LAS on Caspian kutum is important. In the present study, fish exposed to sublethal concentrations of LAS (0.58, 1.16 and 2.32 mg/l) for 192 hours. Control treatments with three replicates at 0, 24, 48, 72, 96 and 192 hours were done. For assessments of the histological effects of LAS, tissue sections prepared and by using Hematoxylin - Eosin were stained, then the prepared sections, examined by light microscopy. For determination of the bio accumulation of LAS, the soxhlet extraction and solid phase extraction was performed to determine the amount of LAS using HPLC with fluorescence detector. According to results average of bioconcentration factor and LAS concentrations in fish had reached stable levels after approximately 72 h and thus represented steady state BCF values in this species. The value of steady-state bio-concentration factor of total LAS was 33.96 L.Kg- 1 and for each of the homologous C10-n-LAS, C11-n-LAS, C12-n-LAS and C13-n- LAS were 3.84, 6.15, 8.58 and 15.57 L.Kg-1 respectively. According to the results obtained in gills exposed to LAS, histopathological alteration include hypertrophy, lifting of lamella epithelium, edema, clubbing of lamellae hyperplasia, lamellar fusion and aneurysm were seen. In liver tissue exposed to three concentrations of LAS, congestion and dilation of sinusoids, irregular-shaped nuclei and degeneration in the hepatocyte, vacuolar degeneration and necrosis were observed. In kidney exposed to three concentrations of LAS, reduction of the interstitial haematopoietic tissue, degeneration in the epithelial cells of renal tubule, tubular degeneration, necrosis, shrinkage and luminal occlusion were observed. According to the results the most alteration due to exposure to LAS was seen in the gill tissue. None of the control samples showed histological effects of LAS.