Iranian Journal of Fisheries Sciences
Volume:14 Issue: 2, Apr 2015

The Astacus leptodactylus specimens were collected from four sites of Aras reservoir, North-West of Iran and examined for the epibionts during 2009. Protozoan epibionts from ciliophora (one genus and seven species) and tracheophyta were isolated from the cuticular surface of different body parts of narrow-claw crayfish, A.leptodactylus. Seasonal prevalence of infestation was determined in 394 individuals of A.leptodactylus. The facultative ciliate Tetrahymena pyriformis was identified on the gills and gill haemocoel with 0.5% prevalence. Futhermore, epibiont fouling organisms such as Epistylis chrysemidis (52.3%); Vorticella similis (45.9%); Cothurnia sieboldii (68.5%); Pyxicola annulata (66%); Chilodonella spp.(0.5%); Zoothamnium intermedium(57.1%); Opercularia articulate (20.6%) and Podophrya fixa (8.6%) were also isolated from 13 body parts of A.leptodactylus. The presence of Chilodonella infestation is the first record of this genus on freshwater crayfish species. The comparison of biometrical data of the epibionts showed no significant differences in prevalence of seasonal infestation between sampling sites. The current work represents the first documentation for the presence of protozoan epibionts on A.leptodactylus in Aras Reservoir, Iran.

Scatophagus argus argus (Green Scat) is a pretty aquarium fish. Its hard spines are venomous and can cause painful injury. In this study 60 specimens of Green Scat were collected periodically from coastal waters of Boushehr (south of Iran) from May 2011 to April 2012. Anatomical features of venomous spines were investigated. Scat venom was extracted from the spines in a new manner for keeping the specimens alive. The nature of venom was tested by SDS-PAGE. Ethical issues and animal welfare principles such as rapid and instantaneous anesthetizing, post operation disinfection and fast recovery of the specimens was practiced in order to minimize the complications. This method enhanced the purity and quantity of venom as demonstrated by 12 separated proteins in electrophoresis. New ethical issues were developed to surviving the specimens and prolong viability as well.

In this study, three different age groups of male broodstocks (4, 5 and 6 years respectively) were used to fertilize eggs obtained from nine females. The results showed that 6 year old males had maximum body weight (1766 g), total length (56.3 cm) and sperm volume (31.83 ml). Results did not show significant difference in spermatocrit and spermatozoa concentration among age groups (p>0.05). Our study showed maximum fertilization rate (98.5 %), survival rate until eyes pigmentation (91.17 %), hatching rate (94.5 %) and survival rate until absorption of yolk sack (97.16 %) for 4 years treatment group. Such positive relationships were detected between sperm production characteristics (spermatozoa concentration, spermatocrit and sperm volume) and fertilization parameters. Based on our results, it can be concluded that 4 year old males have high efficiency leading to fertilization success.

This study evaluated the suitability of canola oil as a source of supplemental dietary lipid for rainbow trout. Triplicate groups of the 30 fingerlings held under identical culture conditions were fed twice daily by iso-nitrogenous, iso-calorific and iso-lipidic diets for eight weeks. Experimental diets consisted of 30.3% protein, 18.7 kJg-1 energy and 16.7% lipid from fish oil (FO), canola oil (CO) and 1:1 blend of the two oils (FCO). Moisture, ash, protein, lipid, final body weight, condition factor, feed conversion ratio, survival and hepatosomatic indices were not affected by treatments. Specific growth rate and weight gain of fish reared on fish oil diet (FOD) and canola oil diet (COD) were significantly higher than those fed with the fish and canola oils diet (FCOD). Protein efficiency ratio was highest in fish fed with the COD. Whole body fatty acid compositions mirrored those of diet treatments. The highest amounts of HUFAs were detected in fish fed with FOD, which was significantly different from other treatments. In all treatments PUFAs/SFAs and n-6/n-3 ratios were higher than 0.45 and lower than 4, respectively. Our results indicate the fingerlings can be reared on diets in which FO has been replaced with CO, with no significant effects on fish growth performance.

The objective of our study was to explain the histopathological changes of monodon baculovirus (MBV) in hepatopancreas and midgut tissues of the cultured Penaeus vannamei. Five-hundred and forty juvenile of P. vannamei with average size of 7.99±0.54 g and 3600 post larvae 10-15 were distributed to 18 glass aquariums (50×50×60cm) with 100L well aerated water per each aquarium as water borne MBV (group A) and food borne MBV (Group B) and one control group (C), in triplicates. Also, 3600 post larvae were dedicated for water borne exposure (D) based on one time immersion exposure in 24 h without water exchange and the untreated group was studied as control in triplicates. The specific pathological sign of MBV was observed as a multiple intranuclear eosinophilic occlusion bodies (OBs) in hepatopancreas and midgut tissues. Our result indicates that the severity of the MBV infection is more considerable in post larvae than juvenile stage and confirms that MBV can be an invasive pathogen for shrimp culture industry in Iran.

Because of limitations of production of unicellular green algae (especially in large volumes), this study aimed to culture Artemia using three sources of cheap agricultural by-products that were coupled with small amounts of unicellular algae Dunaliella salina. The results of growth and survival, biomass production, Individual wet weight, wet and ash percent, FCR and SGR and nutritional value of experiments groups were compared with that of the control group that was reared on a diet completely consisting of green algae. At the end of day 15, although best results in the case of growth and survival and biomass production were obtained in the control, the results of all evaluated parameters experimental treatments were comparable to the control.

Nisin is a widely used naturally occurring antimicrobial effective against many pathogenic and spoilage microorganisms. It has been proposed that reduced efficacy of nisin in foods can be improved by technologies such as encapsulation to protect it from interferences by food matrix components. This study was carried out to evaluate the microbiological quality of fresh trout slices treated with N1 (nisin 0.15 g/kg) and N2 (nisin 0.25 g/kg), NE1(encapsulated nisin 0.15 g/kg), NE2 (encapsulated nisin 0.25 g/kg) and were then packaged under Modified Atmosphere Packaging (MAP) (45% CO2, 50% N2, 5% O2) and stored at 4±1 °C for 20 days. The results revealed that nisin in both forms of free and encapsulated was efficient against the proliferation of various categories of spoilage microorganisms; including aerobic and psychrotrophic populations and lactic acid bacteria. The shelf life of the treated products was extended by 4–7 days more than that of the control. As a consequence, nisin, in particular encapsulated nisin, might be considered as an effective tool in preventing the quality degradation of the fillet, resulting in an extension of their shelf life.

Kilka fish are known as the main industrial and pelagic species of Iran that are captured abundantly in the southern Caspian Sea. This study was conducted to survey the effectiveness of refinement steps on Kilka (Clupeonella delicatula) crude oil quality and fatty acid profiles. Neutralization, bleaching, winterization and deodorization were performed on crude oil with deodorization done under two different conditions of A: at 180˚C for 120 min and B: at 140˚C for 240 min. During refinement, peroxide value (PV) significantly decreased from 7.66 meq/kg in crude oil to 0.5 in deodorized oil A and to 0.21 in deodorized oil B (p<0.05). Significant reduction in free fatty acids (FFA) was recorded from 0.86% oleic acid in crude oil to 0.15% in deodorized oil A and to 0.33% in deodorized oil B (p<0.05). N-3 fatty acids content and fatty acids composition were determined by GC-FID and n-3 fatty acids content increased from 18.74% in crude oil to 21.58% in deodorized oil A and to 21.75% in deodorized oil B. The red color in oil significantly decreased from 5.4 to 0.4 and 0.5 in deodorized oil A and deodorized oil B, respectively (p<0.05). Results confirm that refinement steps improved oil quality and raised n-3 PUFA concentration and n-3/n-6, properly. Deodorization at 180˚C for 120 minutes (A) was more effective than deodorization at 140˚C for 240 minutes (B) in removing off flavors.

The maintenance of the endangered Caspian brown trout Salmo trutta caspius populations in Iran depends on its artificial breeding. There is no information on how current hatchery breeding protocol influences effective population size of breeders (Ne), which is a critical parameter to maintain genetic diversity in future generations. The current hatchery protocol (CHP) was comparatively evaluated with a balanced hatchery protocol (BHP), where mixtures of equal amounts of gametes per male and female breeder were used to balance parental contributions to progeny. To evaluate putative differences in viability between families, individual crosses were performed and fertilized ova of different families were mixed to constitute balanced family pools. 1440 alevins were totally sampled in the crosses performed from the 11 breeders. An exclusion-based parentage approach using three polymorphic microsatellite markers unambiguously assigned more than 93% of progeny to a single pair of parents. Significantly different contributions of breeders to progeny were observed in CHP (p<0.05). The primary constraint on Ne in BHP was the unbalanced contribution of males, which seemed a consequence of sperm competition in mixed fertilization caused by differences in sperm quality. Sperm motility duration was positively correlated with the number of sired progeny by each male. The results illustrate the limitations of the BHP in minimizing the loss of genetic diversity observed in CHP. A protocol based on mixture of equal number of fertilized ova from individual male × female crosses emerged as the best alternative for conservation of Caspian brown trout.

Diadema setosum (Leske, 1778), is one of the common echinoids widely distributed in the Indo-West Pacific Ocean, where it occurs from the Red Sea, Persian Gulf and the east coast of Africa to Japan, Australia and Malaysia. To investigate the developmental basis of morphological changes in embryos and larvae, we documented the ontogeny of D. setosum in a controlled laboratory condition at the Institute of Bioscience, Universiti Putra Malaysia, during July–September, 2012. Matured gametes were obtained from the adult individuals and the eggs fertilized at limited sperm concentration (10-5 dilution). The obtained embryos were then reared at 24-25oC. First cleavage (2-cell), 4-cell, 8-cell, 16-cell, 32-cell and multi-cell (Morulla) stages were attained at 01.20, 02.14, 02.44, 03.09, 03.32 and 03.54 h after fertilization, respectively. Blastulae with a mean length of 111.47±1.88 µm (mean±SD) hatched 08.45 h after sperm entry. Gastrula formed 16.36 h post-fertilization and the archenteron extended constantly, while the ectodermal red-pigmented cells migrated synchronously to the apical plate. The pluteus larva started to feed unicellular algae (Chaetoceros calcitrans) in 2 d, grew continuously, and finally attained metamorphic competence within 35 d after fertilization. Induction of metamorphosis took approximately 1 h 30 min from attachment on the substratum to the complete resorption of larval tissues and the development of complete juvenile structure with adult spines, extended tubefeet and well-developed pedicellaria, the whole event usually took place within 1 d post-settlement. The newly formed juvenile (473.16 ± 6.96 µm, n=30) with a complete adult structure then grew on coralline algae to 3-month old juvenile, which represents the “sea urchin seed” for stocking in grow-out culture. This study represents the first successful investigation on embryonic, larval and early juvenile development of D. setosum. The findings would greatly be helpful towards the development of breeding and seed production techniques for aquaculture of sea urchins.

This study was conducted to determine the optimal dietary protein requirement for lemon fin barb hybrid fingerlings. Triplicate groups of fish (1.00 ± 0.05 g) were fed twice a day until apparent satiation with five isocaloric (16 kJ/g) diets containing varying protein level ranging from 20 to 40% for 60 days. Survival was not affected by the dietary protein level. The weight gain and specific growth rate were improved with dietary protein level up to 35 %. The best feed conversion ratio (1.61) was achieved at 35% dietary protein level. Protein efficiency ratio was not influenced by the dietary protein level. Using a broken line regression model, the dietary protein requirement of lemon fin barb hybrid was estimated at 34.6 % based on weight gain response but the value was not significantly better than the 30% protein diet. Proximate composition of the fish showed that dietary protein level only affected the protein content of the lemon fin barb hybrid. The study showed the protein retention was increased until 30% and decreased above this level. Lipid retention decreased as the dietary protein increased. It can be concluded that lemon fin barb hybrid required 30-35% protein at gross energy 16 kJ/g for the best growth and feed efficiency.

The green colonial microalga, Botryococcus braunii is well known for its high lipid content and has already been proposed as a renewable energy source for various aquaculture and biotechnological applications. However, due to its slow growth rate compared with other microalgae, B. braunii has not yet been used in mass culture to produce more biomass. Therefore, in this study we tested different culture media to enhance the growth rate of B. braunii. B. braunii samples were collected from natural habitat, isolated and purified by repeated streaking on agar plate. The purified samples were cultured in six treatments containing different culture media with incubation conditions of pH 7.5, temperature 25±1°C under 1.2±0.2 klux light intensity with 12 hr photoperiod to observe their growth rate and morphology. The results of this study showed the highest growth rate (µ=0.20 day-1) in the autoclaved lake water with 427 colonies/ml. Bold’s basal medium (BBM) and modified Chu No. 10 medium showed moderate growth after 24 days of incubation. The growth rates amongst all media were significantly different (p<0.05) except between un-autoclaved lake water and autoclaved water medium added with half concentration of BBM. Morphological observation showed that B. braunii varied in different culture media. This study illustrated that autoclaved lake water has the highest growth rate compared to formulated media such as BBM and modified Chu No. 10 medium. This indicates that the autoclaved lake water medium had high concentration of nutrients and can be used for the mass production of B. braunii at lower cost.

White spot syndrome virus (WSSV) is a highly pathogenic and prevalent virus affecting shrimp culture worldwide including Iran. In the present study, a pair of primers was designed according to the sequence of VP 28 gene of WSSV in the GenBank. VP28 gene from an Iranian WSSV isolate (IrVP28) was cloned, sequenced and expressed in Escherichia coli BL21(DE3) strain in order to produce VP28 protein using PET28a expression vector. The expression resulted in a protein of about 30kDa, which was purified under denaturing conditions, resulting in a highly purified final IrVP28 preparation. The obtained recombinant protein can be used in several biotechnology applications, such as production of monoclonal antibodies which could be used in development of diagnostic tools and potential oral vaccination of shrimp with vaccines consisting of VP28 proteins.

In this study, oil was extracted from the liver and visceral fat of Patin (Pangasianodon hypophthalmus) and refined. The yield of oil after refining was 49.98%. The major yield loss (34.20%) happened during the degumming procedure. Fatty acids found in the crude and refined oil were C12:0, C14:0, C14:1, C16:0, C16:1, C18:0, C18:1, C18:2, C18:3, C18:4, C20:0, C20:1, C20:4, C20:5, and C22:6. The dominant saturated, monounsaturated and polyunsaturated fatty acids were C16:0, C18:1 n-9, and C18:2 n-6, respectively. The total amounts of monounsaturated fatty acids did not change significantly during refining procedure (p>0.05), whereas the total amount of saturated and polyunsaturated fatty acids changed significantly (p<0.05). The n-3 to n-6 ratios of crude, degummed, neutralized, bleached, and deodorized oils were 1.11, 1.06, 1.05, 1.02, and 1.01, respectively.

Aquaculture is among the oldest occupations of human being. Over the past quarter of century, the aquaculture industry has grown rapidly. The effect of water containing sodium sulfate on long term compressive strength of concrete of fishing ponds and channels is investigated in this paper. Aim of this paper was to analyze the strength of concrete channels and of aquaculture which are in direct contact with dissolved sodium sulfate. This is an ongoing laboratory investigation which consisted of 480 standard casting concrete cube mix designs and subjecting them to different curing condition environments. Analyzing laboratory results, it was found that for short period of time, the effect was negligible, but for longer periods up to seven months, EC (electrical conductivity) of water had a low negative effect on compressive strength of concrete, while specimens were placed in waters with different ECs. On the other hand, average compressive strength of concrete was almost 25 kg/cm2 lower than estimated. However, loading the sample concretes up to failure resulted in strength loss of up to 10%. To solve this problem, designed compressive strength must be considered 10% higher than actual in order to have an acceptable concrete strength for water channels and ponds which are in direct contact with sodium sulfate ions in the water.

Speckled shrimp (Metapenaeus monoceros), is a commercially important prawn in the embayments and estuaries of the Mediterranean Sea. It is originally a Lessepsian species which had migrated from the Red Sea into the Mediterranean Sea through the Suez Canal. This study was carried out in the North-eastern Mediterranean Sea between November 2009 and October 2010 with monthly sampling of speckled shrimps, by bottom trawl operations. Totally 784 specimens of this shrimp were studied, and the male/female ratio was determined as 1:1.4. The minimum size at first maturity for females was measured as 74 mm TL, and 50% of the female population were mature at about 110 mm (TL50%). It was also determined that female shrimps had developed their eggs between June to October, with two peak spawning periods between June-July, and August and October.

In this paper age determination and morphological characteristics of blacktip catfish, Plicofollis dussumieri, from Oman Sea were evaluated. A total of 132 fish specimens were collected from fishing trawlers or landings from March 2011 to July 2012, with minimum and maximum of 245 mm, 195 g; and 767 mm, 5801 g, respectively. Maximum life span was 12 years for the length range of 245 – 767 mm FL, while total body weight (BW) ranged between 195 and 5801 g and the resultant equation was: W = 0.040 L2.8275 (R2 = 0.99). High correlation coefficient value found between age and FL was R= 0.97 and for age-BW was 0.94. This value for otolith weight and BW was estimated to be 0.91 and showing that there were significant correlations between measured parameters. Lapillus otolith in blacktip catfish is the biggest otolith among most teleostei fishes, also the Sagitta is the biggest. Lapillus of this species is round, robust, onion-like and without sulcus curve, with no obvious growth increments in rostrum and antirostrum zones. In ventral side Gibbus maculae is concave having prominentia marginalis in anterior and basal line in posterior parts.

The analysis of net catches made in Absheron Gulfs of the Caspian Sea during 2011-2012 is provided. The ichthyofauna of Absheron Gulfs, including 26 species found in the North Gulf, and 33 species and subspecies found in the South Gulf was studied for the first time. A taxonomical and ecological diversity of the fish fauna of North and South Absheron Gulfs is characterized. The peculiarities of distribution and population densities of all species of fishes from different families within the studied territories were analyzed. For each of hydrological seasons, numerous, common, infrequent and rare species were revealed. On migration patterns and catch, the lowest biomass of fishes was observed in the warm season, while the highest was in the winter and spring seasons. The tendency of expansion of ranges of some marine fishes-Gasankuli herring Alosa braschnikowi kisselewitschi, Sara herring A. braschnikowi sarensis, big-eyed herring A. braschnikowi autumnalis, Sara shad A.caspia knipowitschi- to the north was recorded.