Iranian Journal of Fisheries Sciences
Volume:17 Issue: 4, Oct 2018

In this study, rainbow trout were fed for a total of 144 days with different feed mixes containing 0.00%, 0.10%, 0.40%, 0.70%, 1.00% and 1.30% black cumin oil. The effect of black cumin oil on growth performance, feed content and fatty acid composition of rainbow trout was researched. The starting weight of fish in the experimental group was approximately 60 g, which increased to 215.21±4.12g, 217.32±3.14g, 235.12±2.9g, 240.21±6.5g, 260.14±4.7g, and 258.89±1.6g, respectively and the differences in growth between the groups were observed to be statistically significant (p<0.05). Black cumin oil decreased the feed conversion rate of the fish. The addition of black cumin oil in the fish feed increased feed consumption and the daily feed consumed per fish for each group was as follows: 0.93g, 0.93g, 0.97g, 1.00g, 1.02g and 1.02g, respectively. At the end of the experiment the economic conversion rates of the fish ($ Kg-1) were between 1.58 and 1.67, while the economic benefit index was between 0.60 and 0.72. The study showed that protein efficiency rates and specific growth rates of the experimental groups had increased. The addition of black cumin oil to the feed increased the proportions of raw protein, oil and raw cinder in the trout and decreased the proportion of moisture, while also increasing the amounts of linoleic, oleic and stearic acids.In conclusion, the addition of 1.00% black cumin oil in feeds increases growth performance in fish and decreases production costs.

In this study, random sampling conducted and 90 individuals of Persian sturgeon having 3-5g weight, collected by trawling in 3 earthen ponds and 15 individuals having 10-20g weight, collected by small net in 3 fiberglass Vans. After recording of biometrical characteristics, the intestine and rearing water were cultured on TSA medium. Gram staining and complementary tests were conducted. In order to identify the bacterial species, various biochemical experiments and diagnosis kit of API 20E (special for gram negative bacteria) applied. According to biometrical recording, in earthen ponds, the mean weight and length of juveniles were 5.59±3.18 and 11.4±2.9, respectively. The results showed that the mean facultative aerobic and anaerobic bacterial counts in intestine were 5.59±0.92 (log CFU g-1) and 6.67±0.34 (log CFU Ml-1) in Acipenser persicus juveniles and rearing water, respectively. Furthermore, the following bacteria determined in intestine of Persian sturgeon: Aeromonas sp., A.sorbia, A.hydrophyla, Entrobacteriaceae and Corynebacterium. The bacteria in the rearing water were Aeromonas sp. and A.soberia. According to biometrical recording, in fiberglass Vans, the mean weight and length of juveniles were 12.13±2.51g and 15.11±1.13 cm, respectively. The results showed that the mean facultative aerobic and anaerobic bacterial counts in intestine were 4.77±0.04 (Log CFU g-1) and 4.81±1 (Log CFU mL-1) in A. persicus juveniles and rearing water, respectively. Furthermore, the following bacteria determined in intestine of Persian sturgeon: Aeromonas sp., Micrococcus, Staphylococcus. The bacteria in the rearing water were Aeromonas soberia, Acinetobacter,Moraxella, Micrococcus and Staphylococcus

This study aimed to assess ecological quality status of hard substratum macroinvertebrates communities of the Caspian Sea with three ecological indices and their relationship with environmental factors. For this purpose, benthic communities of the Caspian Sea basin were studied seasonally during 2014 in 8 sampling sites. Temperature, salinity, dissolved oxygen, pH, nitrate, nitrite, silicate and phosphate were measured as environmental factors. The benthic classification indices AMBI (AZTI Marine Biotic Index), M-AMBI (Multivariate AMBI) and BENTIX (BENthic IndeX) were applied to assess the ecological status of the studied area. Results showed low dissimilarity based on species composition and abundance among seasons, while all seasons discriminated clearly based on environmental factors. In addition, AMBI index was more successful to assess ecological health of hard substratum in the Caspian Sea basin than M-AMBI and BENTIX. Furthermore, AMBI showed high sensitivity to environmental variation. Results indicated that temperature, nitrate, silicate, phosphate and nitrite were the most important factors in the composition and abundance fluctuation of hard substratum macroinvertebrates communities, respectively.

Population growth (length-weight relationship), and reproductive potential (e.g. fecundity, and sex-ratio) of five important fish species (‘mola’: Amblypharyngodon mola, ‘puti’: Puntius sophore, ‘tengra’: Mystus vittatus, ‘shing’: Heteropneustes fossilis and ‘taki’: Channa punctatus) collected from two important fresh water bodies (namely Hilna beel and Beel Kumari beel) Rajshahi, Bangladesh, were studied. Population growth pattern by length-weight relationship (W=aLb) for the species differed, and exhibited positive allometric growth (P. sophore in Hilna beel), isometric growth (A. mola and C. punctatus in Hilna beel) and negative allometric growth (M. vittatus & H. fossilis in Hilna beel and A. mola, P. sophore, M. vittatus, C. punctatus and H. fossilis in Beel Kumari beel). The results denoted that fecundity of mature females followed a non-linear relationship (F=aLb) with total length and exhibited positive allometric growth (b>3) with some exception (A. mola in Hilna beel and M. vittatus in Beel Kumari beel). Fecundity of mature females also increased with total body weight and ovary weight following a linear relationship (F=a+bW). Differences in values of sex-ratios with seasons for all species in this study may have resulted from different environmental factors as well as breeding seasons. The findings of this study would be useful in imposing adequate regulations for the conservation of these fascinating fishes in the fresh water bodies of Bangladesh.

This study aimed to elucidate the influence of environment pH on survival, growth, energy allocation and oxidative damage of juvenile Scophthalmus maximus (19.89±0.25 g). Six pH treatments (6.3±0.2, 6.8±0.2, 7.3±0.2, 7.8±0.2, 8.3±0.2, 8.8±0.2) lasting for eight weeks were included. Measurements of survival (SR), feed conversion ratio (FCR), specific growth rate (SGR), weight gain rate (WGR), energy allocation, liver superoxide dismutase activity (SOD), catalase activity (CAT), and malondialdehyde concentration (MDA) were done. Results show that SR did not vary from pH 6.3 to 7.8, but reduced then significantly (p<0.05); FCR raised remarkably (p<0.05) while SGR and WGR decreased pronouncedly (p<0.05). Most of the food energy was used in metabolism, followed by growth, feces loss and nitrogenous excretion. Energy deposited for growth showed a decreasing tendency when pH raised; while for metabolism showed a reverse trend. SOD showed insignificant difference from pH 6.3 to 7.8, but the activities then elevated obviously (p<0.05) though a slight decrease was found from pH 8.3 to 8.8 (p>0.05). CAT kept stable between pH 6.3 and 7.3, then sharply increased (p<0.05), but no significant differences were found between pH 8.3 and 8.8 (p>0.05). Subsequent decrease in MDA was found from pH 6.3 to 8.3 then the concentration smoothly increased. Overall, our results indicate that a pH in the range of 6.8 to 7.8 is recommended in the growth environment in cultivation of juvenile turbot.

Variation of hydrochemical conditions, with special reference to adequacy of waters as fish habitats, was traced based on selected hydrochemical parameters obtained during the studies conducted from February 2013 till February 2014 year. The results were compared with earlier studies. The sources of organic pollution were identified, and the effect of biogenic substances on the biomass, as well as the self-purification capability of the river, were assessed. The total suspension exceeded the requirements for waters which are habitats of both salmonid and cyprinid fishes. Compared to the previous years, the load of organic and inorganic matter in the waters of Wiśniówka River increased; this may have resulted from external inflow, neighbourhood of the hatchery but also, to a small extent, from internal supply. The high availability of nitrogen-(N-NH4+; N-NO2-, N-NO3-) and phosphorus-(total phosphorus; P-PO43-) based biogenic (substances favoured the biomass production, thus contributing to the increase in organic matter load in the river.

Nonylphenol (NP) is an endocrine disrupting chemical which has been shown to be able tomodulate endocrine system of various organisms by different mechanisms. The objective of this study was to investigate the potential effects of 4-NP and 17-β - estradiol (E2) on the immune parameters (IgM levels and lysozyme activity) of the teleost Koi carp (Cyprinus carpio carpio) for a better understanding of the immune-reproductive system interactions. The experimental fishes were injected with ascending doses (10, 50,100 μgg-1 body weight) of 4- nonylphenol (4-NP) and (2 μgg-1 body mass) of 17-β-estradiol (E2) or vehicle during 3 weeks. After 21 days, the fishes (180) were anesthetizedand their blood samples were collected from caudal vein, then they were dissected and sexually separated by gonad characters. The measurement of immune parameters in plasma showed that 4-NP induced significant increase in the IgM levels and lysozyme activity at dose of 50 μgg-1 while the levels of these parameters in the higher doses (100 μgg-1) decreased compared with the control group (p<0.05). In addition the treatment, with 2 μgg-1 E2 significantly decreased both the IgM levels and lysozyme activity after 21 days of injection. These results indicated that 4-NP and E2 could lead to disturb the balance of immune system with potential consequences for immature koi carp.

A 10-week feeding experiment was conducted to evaluate the effects of feeding level, energy and protein maintenance requirement of rainbow trout, Oncorhynchus mykiss, fingerling (5.65±0.45cm; 1.42±0.25g) by feeding casein-gelatin based purified diet (45% CP; 3.67 kcal g-1 GE) at six feeding levels from 2 to 7% of BW/day in two equal meals, at 0800 and 1700 h, in triplicate, with 20 fish per trough equipped with continuous water flow-through system water (60L volume). Maximum live weight gain, best feed conversion ratio (FCR), best specific growth rate (SGR) and highest protein efficiency ratio (PER) were reported in fish fed 4-5% BW day-1. However, quadratic regression analysis for weight gain, FCR, PER, protein retention efficiency and energy retention efficiency data indicated the break-points occurred at 5.33, 4.50, 4.48, 4.63 and 4.74% BW day-1, respectively. Body composition also produced significant (p<0.05) differences with respect to each feeding level, maximum protein, lowest moisture and intermediate fat contents were reported at 4-5% feeding levels. Protein and energy retention values also produced significant (p<0.05) differences among each feeding level with maximum values were reported at 5% feeding level. Based on the results, it is recommended that feeding in the range of 4.6 to 5.3% BW day-1, corresponding to 2.07-2.39g protein and 16.88-19.45 kcal energy g100g-1 of the diet day-1 is optimum for the growth and efficient feed utilization of rainbow trout, while 2-3% feeding levels (0.90-1.35g protein and 7.34-11.01 kcal energy) suggests that these amounts approximate the maintenance requirement of fish.

The high density of Basa fish (Pangasius bocourti) culture leads to outbreaks of Ichthyophthirius multifiliis (Ich), also knows as white spot disease. In this research, immunization of Basa fish against Ich with live and sonicated trophonts by intraperitoneal (IP) injection was investigated. Anti‑Ich antibody titer was determined using ELISA and Western immunoblotting 21 days post immunization. The results revealed that pre-immunized fish, non‑immunized fish and fish immunized with bovine serum albumin (BSA) at a concentration 65 µg g-1 fish did not show specific antibody against Ich. 21 days post immunization, fish immunized with live trophonts exhibited higher anti‑Ich antibody titer than fish immunized with sonicated trophonts at the same antigen concentration. Fish immunized with 65 µg trophonts protein/g fish live trophonts showed the highest titer 1:1,000 (p<0.05). The results from Western immunoblotting showed two parasite protein bands of 66 kDa and <14 kDa, which reacted with antibodies from serum of immune fish. No fish in the non-immunized group survived. At the same concentration of antigen (65 µg g-1), fish immunized with live trophonts exhibited the highest survival rate, 63.33±5.77% (p<0.05). Therefore, these results are the Basa fish immunizing procedure will be the way to conduct immunization against Ich to prevent disease outbreaks in aquaculture.

The purpose of this study was to find some important biological aspects of Thunnus tonggol in coastal waters of Hormozgan Province (Persian Gulf and Oman Sea). A total monthly data of 4383 individuals ranging from 25 to 124 cm fork length were collected from April 2015 to March 2016. The data were analyzed with FiSAT II software using the ELEFAN1 package to estimate the population parameters. The length-weight relationship was TW=0.00002 FL2.87 (R2=0.97) showing an isometric growth for T. tonggol. Growth parameters were computed as L∞=129.6 cm, K=0.39 year-1 and t0=−0.28 with the growth performance index, φ’ of 8.7. The total mortality (Z) was estimated 1.58 year-1 using catch curve method. The natural (M) and fishing mortality (Fcurr) were obtained 0.49 and 1.09 year-1, respectively. The exploitation ratio was 0.69. Length at first capture (Lc) was estimated as 60.2 cm fork length. The yield per recruit (Y/R) maximized in maximum fishing mortality rate 0.85 year-1. The biomass per recruit decreased to 17.2% of unexploited biomass (virgin biomass) at Fcurr. The current fishing mortality exceeds optimum fishing mortality (Fopt) and limit fishing mortality (Flimit) as biological reference points. The results indicated that population of T. tonggol is overexploited in the Persian Gulf and Oman Sea and there no further scope for improving the exploitation of this species.

The effects of various salinity levels among (0‰, 5‰, 10‰, 15‰, and 20‰) for successful breeding of common carp, Cyprinus carpio were investigated. The duration of study was 75 days. Ripe broodstock (30) having a mean weight (male 1027±2.4g and female 1084.8±23g) were selected and stocked into spawning tanks (2000 L). The ratio among male and female was 2:1. They were fed with commercial floating pelleted feed having 35% crude protein with 2% body weight twice a day. Broodstock were injected with ovaprim hormone 0.5 mg kg-1 female and male 0.2 mg kg-1 respectively, after successful spawning broodstock were removed from spawning tanks. The results showed that the highest fecundity, fertility, hatchability and survival of fry were obtained on salinity of 0‰ to 10‰ and significantly decreased on 15‰ and 20‰. The eggs per gram body weight were also recorded in all treatments and highest eggs were obtained, i.e. 45-60 per female on salinity of 0‰-10‰. Water temperature (22.4±0.2°C), dissolved oxygen (6.5±0.2 mg L-1), pH (7.2±0.2) and ammonia (less than 0.03±0.06 mg L-1) were monitored throughout the study period. Water quality parameters remained within the recommended range. Our results suggest that common carp, C. carpio may give maximum eggs up to 10 ‰ salinity with 81% survival of the fry.

Over the last two decades, improvements in developing computational tools have made significant contributions to the classification of images of biological specimens to their corresponding species. These days, identification of biological species is much easier for taxonomists and even non-taxonomists due to the development of automated computer techniques and systems. In this study, we developed a fully automated identification model for monogenean images based on the shape characters of the haptoral organs of eight species: Sinodiplectanotrema malayanum, Diplectanum jaculator, Trianchoratus pahangensis, Trianchoratus lonianchoratus, Trianchoratus malayensis, Metahaliotrema ypsilocleithru, Metahaliotrema mizellei and Metahaliotrema similis. Linear Discriminant Analysis (LDA) method was used to reduce the dimension of extracted feature vectors which were then used in the classification with K-Nearest Neighbor (KNN) and Artificial Neural Network (ANN) classifiers for the identification of monogenean specimens of eight species. The need for the discovery of new characters for identification of species has been acknowledged for log by systematic parasitology. Using the overall form of anchors and bars for extraction of features led to acceptable results in automated classification of monogeneans. To date, this is the first fully automated identification model for monogeneans with an accuracy of 86.25% using KNN and 93.1% using ANN.

This study was conducted to evaluate histopathological responses in liver, gills and kidney in Rutilus caspicus exposed to concentrations of 50, 100, 150 mg L-1 of methyl tert-butyl ether, for 7, 14, and 21 days. The experiments were conducted in water temperature of 19±1 °C, dissolved oxygen of 7.6 ± 0.2 mg L-1 and zero salinity. A total of 156 fish were studied in this experiment. In the first, second and third week of the experiment, three fish were taken randomly from each aquarium. To examine the tissues, the liver, gills and kidney were isolated and prepared for evaluation using standard histological techniques. Tissue damage in the liver includes: blood congestion, congestion of sinusoid, melano macrophage aggregation, hepatocyte hypertrophy, vacuolation, degeneration and cellular necrosis. Gill tissue damage includes: hyperplasia, degeneration lifting, telangiectasis, in secondary lamellae, blood congestion in primary and secondary lamellae, S formation of lamellae, reduction in length of secondary lamella, lamellar fusion and cellular necrosis. Tissue damage in the kidney includes: tubular shrinkage, blood congestion, melano macrophage aggregation, glomerular shrinkage, cellular necrosis, tubular degeneration, reduction in interstsial cells and interstisial hematopoietic tissue degeneration. The amount of tissue damages in high concentrations of pollutants was high, while gill, liver and kidney in the control group was observed in the normal outline. The results of this study showed that methyl tert-butyl ether (MTBE) can cause damage in vital tissues of R. caspicus and even, eventually lead to death.