International Journal of Aquatic Biology
Volume:2 Issue: 6, Dec 2014

This study was conducted to evaluate the effects of Beta plus probiotic, a mixture of Bacillius leicheniformic and Bacillius subtilis, on the growth performance and intestinal microbial flora of Caspian trout (Salmo caspius). A basal diet was formulated and supplemented with Beta plus at 0, 0.5 and 1 g kg-1, leading to three experimental diets. Each experimental diet was randomly assigned to quadruple 1500 L tanks. The Caspian trout with an initial weight of 108.7 ± 1.8 g were randomly distributed in the experimental tanks. The results showed that inclusion of dietary Beta plus significantly increased the final weight and specific growth rate (SGR) of Caspian trout compared to those the control treatment. The feed conversion ratio (FCR) was also improved significantly after probiotic administration to the experimental fish. However, the body composition and blood parameters were not influenced by the probiotic inclusion. Total count of Gram positive and negative bacteria in the intestine of the fish increased by feeding on diet contained 1 g kg-1 Beta Plus (P<0.05). In conclusion, administration of the probiotic Beta plus can improve the nutrient efficiency and growth performance of Caspian trout confirming the positive effect of a mixture of Bacillus spp.

We performed a plankton survey of blood cockle larvae, Anadara spp., and histological observations of the gonads of adult blood cockle, Anadara granosa, in the coastal waters off Sungai Buloh, Peninsular Malaysia from October 2010 to April 2011. The histological observations indicated the main spawning period in both sexes was from November to March. In addition, the occurrence of blood cockle larvae peaked in November and March. Furthermore, a comparison of the distribution between umbo-stage and full-grown larvae suggested the umbo-stage larvae diffused offshore and return to coastal sites where they settle and mature into full-grown larvae.

siganga stream is an important tributary of Bhagirathi River in central Himalaya (India). The stream is characterized by heterogeneity in habitat and substratum features harboring diverse fish fauna. At present this stream is facing threat of being fragmented by the construction of two hydro-electric projects. Present study aimed to study fish diversity and their habitat use in Assiganga stream. This study reports fifteen species (14 indigenous and 1 exotic) belonging to 8 genera, 4 families and 3 orders. Snow trout, Schizothorax richardsonii (Cyprinidae family) and Salmo trutta (Salmonidae family) were the dominant species (> 65% of total fish catch) throughout the entire length of stream. The presence of rich benthic food, clear water, low turbidity (01-05 NTU), high DO (8.75-10.75 mg-l), and high water velocity (1.10-1.40 m-s) with characteristic rapids and cascades in upper reaches provides ideal habitat for the existence of native snow trout and exotic trout species. Few cat fishes, loaches, Tor spp. and lesser barils also have been reported during the study.

The lowest lipid levels of Capoeta erhani observed in winter and vice versa in summer. The fatty acid composition of the fillets was significantly different among seasons (P<0.05), while the variations among sexes were not at the same degrees (P>0.05). The ratios of the unsaturated fatty acids (UFAs) were higher than half of the total fatty acids among all seasons. The level of PUFA was highest in autumn (25.91%), and lowest in summer (22.11%). Among seasons and sexes, the levels of total n3 PUFAs in total fatty acids changed from 15.43% to 21.89% and n6 PUFAs from 3.8% to 7.97%, respectively. The level of n3 PUFAs was present in excess that of the n6 PUFAs. The ratios of the n3 PUFAs to n6 PUFAs in the fillets of C. erhani were highest in autumn for both sexes and remarkably influenced by seasons.

Anzali Wetland is one of the most important aquatic ecosystems of Iran located at southwest of the Caspian Sea. This wetland is a habitat for valuable fish with vital role in life cycle of this ecosystem. Assessment of pollutants concentration is rational due to complications of determining biological effects in a habitat. The present study examined the concentration of lead (Pb) and cadmium (Cd) in muscles and livers of two fish species i.e. Perca fluviatilis and Tinca tinca collected from Anzali Wetland, and their relationships with fish size (length and weight). The results showed the highest concentration of metals in liver, and the lowest in muscle tissues of both species. Highest concentrations of Cd (0.09) and Pb (3.66) were recorded in liver tissue of T. tinca. The results also showed significant negative correlation between metal concentrations and fish size. Highly significant (P<0.01) negative relationships were observed between fish length and Pb concentrations in liver of P. fluviatilis. Cd and Pb concentrations in liver of P. fluviatilis and Cd concentrations in the liver of T. tinca showed significant negative relationships (P<0.05) with size factors. The concentrations of Pb and Cd were lower than the maximum acceptable concentrations for fish proposed by MAFF thus safe for human utilization.

Cobitis sp. is an endemic spined loach species from the Dough River in the southern Caspian Sea basin, (Golestan Province, Iran). To provide some reproductive features of this fish, sampling was performed at monthly intervals throughout the year and 417 individuals were collected. The specimens ranged in total length from 27.1 to 92.9 mm and total weight from 0.11 to 6.79 g. The spawning of spined loach of Dough River occurs from March to June. The highest mean value of gonadosomatic index (GSI) observed in April as 1.96 for males and 6.61 for females. Egg diameter ranged from 0.3 to 1.3 mm, with a mean value of 0.9 mm. Absolute fecundity varied from 155.04 to 3212 eggs. Fecundity relative to total weight fluctuated from 55.41 to 634.76 eggs g–1. This species is among those spawning early in spring compared to other species of this genus from southern Caspian basin.

A 15-landmark morphometric truss network system was used to investigate the hypothesis of population fragmentation of Shad fish Alosa braschnicowi Borodin, 1904 along the southern Caspian Sea. A total of 181 A. braschnicowi specimens were caught from six localities, respectively from the west to the east including; Astara, Rezvanshahr, Anzali, Tonekabon, Sari and Miankale. Principal component analysis, canonical variates analysis and clustering analysis were used to examine morphological differences. Univariate analysis of variance showed significant differences between the means of the six groups for 72 standardized morphometric measurements out of 105 characters studied. In canonical variates analysis, the overall assignment of individuals into their original groups was 71.46% and scatter plot of individual component scores between CV1 and CV2 showed fish specimens grouped into six areas. Clustering analysis based on Euclidean square distances among groups of centroids using UPGMA resulted into six main clusters indicating morphologically distinction populations of A. braschnicowi in the region. These populations of A. braschnicowi are distinguished especially by head shape, eye diameter, and pre-dorsal, pre-pelvic and pre-anal distances. Therefore, it is suggested considering these morphologically different populations as distinct stock in the southern Caspian Sea coasts.

Cobitis keyvani is recently described from the sourhern Caspian Sea basin. Limited information is available about morphological features of C. keyvani, therefore this study was conducted to provide osteological characteristics and cranial myology of this species. For this purpose, nine specimens of C. keyvani were collected from the Talar River. The specimens were cleared and stained with alizarin red S and alcian blue for osteological examinations. The detailed skeletal structure and cranial muscles of C. keyvani were provided. Based on the results, C. keyvani can be distinguished from other members of the genus Cobitis by a contact between sphenotic and supraoccipital and a contact between pterosphenoid, parasphenoid, prootic and sphenotic in terms of osteological features.

In this study, the concentration of Calcium (Ca), Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Potassium (K), Magnesium (Mg), Manganese (Mn), Selenium (Se) and Zinc (Zn) as essential metals, were determined in caviar of wild beluga sturgeon caught from the Caspian Sea in March 2012. Potassium (4885.51± 17.81 µg g-1) and Magnesium (346.61± 6.6 µg g-1) had the highest concentration and Cobalt and Manganese levels were less than 0.01 mg kg-1 wet weight. The mean concentration of Copper and Zinc in the caviar samples were under the permissible limits proposed by the UK’s Ministry of Agriculture, Fisheries and Foods. The caviar maximum allowable daily consumption rate was calculated. However, the health risks from caviar consumption are uncertain because the amount of caviar consumed by heavy users is not known.