JOURNAL OF FISHERIES SCIENCE AND TECHNOLOGY (JFST)
Year:2020 | Volume:9 | Issue:1|Papers Count:7

Aims In the present study, a three-dimensional numerical hydrodynamic model with the capability to simulate the diffusion of chemical pollutants released in marine basins was developed and used as a case study to simulate the diffusion of phosphate released by fish culture cages located in the Sisangan marine basin. Materials & Methods The equations of the model including momentum equations, continuity of mass equation, temperature, salinity, representative of vertical velocity, the tendency of bottom pressure equations and an extra three-dimensional advection-diffusion equation for simulation of pollutant’ s diffusion rewritten in the earth’ s spherical coordinates with a vertical Sigma coordinate were solved using finite difference method. To provide the open boundary conditions, the model was used for simulation of wind driven currents in the Caspian Sea from 20 October 2018 to 20 May 2019. For the application of wind field and real geometric condition, it was used the time series of wind fields supplied by ECMWF reanalysis dataset and GEBCO bathymetry with 0. 125 degrees resolution and 15 seconds of geographical resolution, respectively. Findings Considering the concentration of 17ppb for the phosphate as a concentration of pollutant in the source of the pollution in the location of the fish culture cages, wind induced currents and the diffusion of the phosphate were simulated for 8 months in both horizontal and vertical directions. The results of the simulations were demonstrated and analyzed within the framework of the horizontal surface current, distribution of the phosphate’ s concentration in both horizontal and a vertical latitude-depth cross section. Conclusion The phosphate’ s diffusion is affected by the wind induced currents and after 8 months, it could be extended to the distance of 11, 8. 5, 9. 5, and 5. 7 kilometers far from the cages in eastern, western, southern, and northern directions, respectively. With the generation of vertical velocity and the turbulence effects in the upper layers, phosphate might be diffused in the vertical direction up to 400m depth, as well.

Aims The objective of the current study was to investigate the effects of three commercial prebiotics including A-Max, Celmanax, and A-Max Ultra (each of them 0. 5, 1, and 1. 5g/kg diets) on growth, feed performance, and blood biochemical compounds of beluga juvenile. Materials & Methods 900 fish with an average weight of 21. 5± 0. 89g were feed in 9 treatments (with three replicate) for 60 days. Control treatment was without supplementation. Fish were fed to satiation triple daily of 5% body weight. At the end of this period, the feed and growth performance were measured. Findings There was a significantly higher final body weight in A-Max ultra 0. 5g/kg (90. 00± 21. 78g) compared with control (37. 50± 9. 60g). The highest and the lowest of food conversion were in control and A-Max ultra 0. 5g/kg treatments, respectively. The results showed that the highest fat and protein efficiency ratio was obtained in prebiotic treatment (A-Max ultra 0. 5g/kg) as 2. 19± 0. 77 and 7. 37± 2. 60 and the lowest was obtained in control. Generally, the best treatments were in groups of Celmanax (dose of 0. 5g/kg), A-Max (dose of 1. 5g/kg), and A-Max Ultra (0. 5g/kg). In addition, after determining the proper dose, blood samples of fish were collected in the above-mentioned treatments. Based on the results of blood biochemistry parameters, there were no significant differences AST, ALP, and ALT activity, so that the highest amount was obtained in the control. Also, there were no significant differences in protein and cortisol experiment groups. Conclusion The use of prebiotics in juvenile sturgeon diet has positive effects on feed performance, liver enzymes, and blood biochemical parameters.

Aims The present study aims to assess the toxicity of CuO and ZnO nanoparticles (NPs) at laboratory conditions on some pathogenic bacteria for the reared fish, as well as, a bioassay on rainbow trout. Materials & Methods For this purpose, the sensitivity of some bacteria to the mentioned NPs with a reference antibiotic (florfenicol) was assayed through the well diffusion method, as well as, minimum inhibitory concentration/minimum bactericidal concentration (MIC/MBC) were determined by microdilution technique. On the other hand, the lethal toxicity test has been accomplished to the calculation of median lethal concentration (LC50) on some rainbow trout (55. 3± 7. 6g) in static condition for the 96 consecutive hours. One-way ANOVA and Probit regression were used in order to data analysis. Findings The results showed that NPs of copper oxide and zinc oxide could significantly inhibit the growth of Streptococcus iniae or kill it at 0. 18 and 0. 24µ g/ml and more, respectively. The comparison between LC50-96h quantities of CuO NP (107. 4µ g/l) and ZnO NP (102. 3µ g/l) indicated that the CuO NP has more toxic potential. Conclusion According to the laboratory findings, the susceptibility of S. iniae and L. garvieae to ZnO NP was close to florfenicol. The mortality in the fish species due to lethal toxicity would occur if the effective concentration of NPs on the bacterial pathogenic agents being used directly.

Aims Monitoring of the fish biomass is one of the basic principles of fisheries management, but ornamental and reef fish stocks, because of difficulty of estimating their abundance, have been less studied than others. The aim of the present study was to estimate the standing biomass of ornamental and reef fishes in Larak Island, in the Persian Gulf. Materials & Methods Standing biomass of ornamental and reef fishes was assessed seasonally using Underwater Visual Census Method (UVCm) in coral reefs and mesophotic coral reefs in Larak Island throughout 2018-2019. Two popular methods in UVCm (belt transect and stationary point) were used based on topography of sea bottom. The confidence interval of estimated standing biomass is calculated using bootstrapping method. Findings The standing biomass of ornamental and reef fishes is estimated as 2522. 18, 5222. 17, and 1325. 15kg in Site 1 (Juvenile of corals and dead corals), Site 2 (dead corals covered with microalgae), and Site 3 (rock and hard coral), that are located in 3-15 meters depth. The standing biomass at Site 4 (rock, hard coral, and Gorgonium spp.; depth 43m), was estimated as 884. 13kg. The least biomass was observed in summer and there is a significant relationship between this season and others (p<0. 05). In addition, the population structure of fish in the spring, autumn, and winter seasons was similar but significantly different from the population structure in summer. Conclusion The Abudefduf vaigiensis, Chromis weberi, C. xanthopterygia, Dascyllus trimaculatus, Pomacanthus maculosus, and Cheilodipterus spp. species appear to be used for the development of ornamental fish aquaculture industry, and Lutjanus fulviflammus, Diagramma pictum, Pomadasys kaakan, Pomadasys stridens, Pomadasys maculatum, Sphyraena jello, and S. putnamiea species can be commercially harvested, although they need to be investigated to determination of total allow catch (T. A. C).

Aim: The purpose of this study was to investigate the effect of replacement of copper sulfate with nano oxidase in diet on growth and survival, enzymatic activity and pathology of liver tissue of goldfish in 2018. Material and Methods: Experimental treatments consisted of 5 control treatments, 3 mg / kg copper sulfate; 3 mg / kg nano-oxide, 5 mg / kg nano-oxide and 10 mg / kg nano-oxide, and fish were given 4% by weight twice a day for 60 days. The body was fed manually. At the end of the trial period, growth and survival indices, liver enzymes activity (alkaline phosphatase, aspartate transaminase, alanine, Aminotransferase) as well as liver tissue pathology were evaluated. Finding: Based on the results, using copper nanoparticles at different levels of 3, 5 and 10 mg / kg diet instead of copper sulfate in the diet can improve the growth performance and survival of goldfish. Copper sulfate also has more negative effects on liver tissue than nanoparticles, as well as alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase enzymes; therefore, the replacement of copper sulfate with copper nanoparticles in the diet seems to reduce the effects of water. On the other hand, histopathological results of liver tissue treatment with 5 and 10 mg Cu / kg diet showed that Cu nanoparticles cause tissue lesions and deleterious effects (albeit less than copper sulfate). Conclusion: Copper sulfate with copper nanoparticles at levels of 3 mg / kg diet To be carried out.

Aims: The aim of this study was to investigate the effect of dietary lemon peel (Citrus limon) essential oil on growth, hematological parameters, some of serum biochemical parameters and liver enzymes in rainbow trout (Oncorhynchus mykiss) juveniles. Materials & Methods: For this purpose, 144 rainbow trouts with an average initial weight of 95. 05 ± 0. 41 g were randomly stocked in four treatments containing different levels of lemon peel essential oil ( 0 (control), 200, 400 and 600 mg lemon peel essential oil/kg diet) and fed for eight weeks. Findings: The results showed the highest growth factors in treatments of 400 and 600 mg lemon peel essential oil/kg diet (p<0. 05). Inclusion of essential oil in diet increased hematological parameters as compared to the control except MCV, MCH, MCHC and increased serum biochemical parameters by contrast to the control except glucose, triglyseride and cortisol (p<0. 05). liver enzymes of ALT and AST showed no significant differences among treatments containing essential oil and LDH exhibited no significant differences among 400, 600 mg essential oil/kg diet and the control treatment (p>0. 05), but ALP amount significantly increased in essential oil treatments in a comparison to the control (p<0. 05). Conclusion: Overall, these results indicated using 400 mg essential oil in rainbow trout diet could improve growth, hematological and some serum biochemical parameters of rainbow trout without any negative effects on liver.

Aims: In the present study, the morphometric and meristic traits of Alburnus chalcoides from the Chelvand (Astara), Khalesara (Talesh), Siahdarvishan (Anzali wetland), Sefid and Pol (Guilan Province), Tonekabon and Babol (Mazandaran Province) rivers were compared. Materials & Methods: For this purpose, a total of 170 specimens were collected from above-mentioned rivers. In the Lab some 39 morphometric and 10 meristic traits were recorded. All data were analyzed by using One-Way ANOVA, Duncan test, Kruskal-Wallis, principal component analysis (PCA), canonical variate analysis (CVA) and cluster analysis. Finding: The results showed a significant difference in 36 morphometric and five meristic traits among the studied populations. CVA result separated the studied populations in the southern parts of the Caspian Sea basin. Also, cluster analysis placed the Chelvand River population in a distinct clade. Conclusion: This study showed high diversity of morphometric compared to meristic traits and better performance of these traits in population's distinction.