JOURNAL OF APPLIED ICHTHYOLOGICAL RESEARCH
Year:2013 | Volume:1 | Issue:3

The present paper aimed at evaluating the nutritional value and fatty acid profile of muscle in cultivated cyprinids (Grass carp, Silver carp, Big head carp, and Common carp). No significant differences were found between the chemical composition indices (i.e. protein, lipid, ash, and moisture) among cultivated cyprinids (P<0.05). In all of the four species, Palmitic acid (C16:0) and Oleic acid (C18:1 &omega;-9cis) were found to be the most abundant saturated and monounsaturated fatty acids, respectively. Oleic acid was significantly higher in common carp than other three species (P&le; 0.05). The most abundant PUFA were linoleic acid (C18:2 &omega;-6) in the common carp, decosahexaenoic acid (DHA, C22:6 &omega;-3) in grass carp and big head carp and arachidonic acid in silver carp. &omega;-3 fatty acid content in grass carp was higher (33.17±6.22) and had significant differences with silver carp (16.71±0.28) and common carp (9.26±5.1) (P&le;0.05). The results of this study also indicated that &omega;-3/&omega;-6 ratios were higher than 1, except for Common carp. &omega;-3/&omega;-6 ratios were 2.02±0.28, 1.66±0.29, 1.16±0.13 and 0.61±0.15 in Big head carp, Grass carp, Silver carpand Common carp, respectively. &omega;-3/&omega;-6ratio in all the species exceeded the eligible rates proposed by nutritionists. The Highest ratios of PUFA/SFA were observed in grass carp (2.23±0.29) (P&le;0.05) followed bythe bighead carp (1.41±0.12), silver carp (1.25±0.22) and common carp (0.98±0.23), respectively. These rates exceeded the eligible rate (0.45) recommended by HMSO for all the species in this research. It is noteworthy that all four species are of similar nutritious value. However, the Grass carp and Big head carp containhigher rates of PUFA, &omega;-3, &omega;-3/&omega;-6, PUFA/SFA, EPA+DHA than the Silver carp and Common carp.

Trichlorophon is one of the organophosphate poisons that are used with different objectives in aquaculture. The current study dealt with the measurement of acute toxicity caused by Trichlorophon on six species of ornamental fish, namely the red sword tail, Tiger, Barbie, bright tetra, guppies, Green-fin molly and Gambusia. To this end, all species were exposed to 5 treatments (with three replicates for each treatment) under different concentrations of toxin containing 0, 5, 10, 20 and 40 ppm They were treated for 96 hours and the rate of mortality was recorded. Toxicity tests were determined using probit analysis in the statistical software SPSS (version 16). At the end of the experiment, the LC50 96 hours of Trichlorophon in the red sword tail, Tiger, Barbie, bright tetra, guppies, Green-fin molly and Gambusia were 7.99, 8.74, 8.88, 9.80, 9.80 and 9.95 mg/liter, respectively. Eventually, Trichlorophon was classified as partly toxic for ornamental fish causingvery similar lethal ranges for all six species, though the red sword tail fish was more sensitive to this toxin.

The effects of fishing mortality on the spawning potential of a stock. In presentresearch, spawning stock biomass of Otolithes ruber was carried out using Virtual Population Analysis (VPA) data (based on previous study) in the coastal waters of North-West Persian Gulf. Spawning stock biomass ranged from 4110 to 11756 tonnes, and fishing mortality ranged from 0.28 to 0.96 per year. Spawning stock biomass per recruit ranged from 22.8 to 44.7%, and avererage spawning potential ratio estimated between 26 to 31%. Fisheries mortality showed a strong and negative correlation with spawning stock biomass per recruit. Percentage spawning potential and SSB/R showed that they are lower in the some years in the range of biological reference points. However, this assessment finds that the stock is near full exploited. But according to reference point’s results, sustainable stocks need actual planning by fishery managers.

A 12-week feeding experiment was conducted to evaluate the effect of dietary betaine as a feed attractant on growth, survival and resistance to some environmental stressors on wild Common carp (Cyprinus carpio Linnaeus, 1758) juvenile. Fish by the weight of 2.51±0.07 g and density of 20 fish per aquarum. Put through Six treatments of different levels of betafin including 0 (control), 0.5%,1%, 1.5%, 2% and 2.5% added to diet containing 35% protein and 3% lipid. At the end of experiment, final growth and feeding indices including final weight ,food conversion ratio ,specific growth rate ,survival rate and resistance to environmental stressors including thermal (35oc) and salinity (35 g/lit) stress assessed. According to the results of this study, a general enhanced growth performance and feed efficiency were observed in fish fed on the diet containing 2.5% betain (P<0.05). There were no significant differences in survival rate among all treatment groups (P>0.05). The highest of survival time after salinity and thermal challenge were observed in 2.5% betain (P<0.05). The results showed that the addition of betain at the level of 2.5% to the diet of wild common carp improves growth performance, feeding efficiency and resistance to environmental stress.

Study of longline&#39;s was carried out to identify the catch composition on the Persian Gulf water. The study areas were from Arvand-Rod to Musa- Khor. Sampling was carried out in three season’s spring, summer and autumn (9 mounths) on a cruise through out month.Twelve specie were caught and indentified. catch composition consisted of Acanthopagrus latus (Houttuyn, 1782), Acanthopugrus bifasciatus (Forsskal, 1775), Lethrinus nebulosus (Forsskal, 1775), Rachycentron canadum (Linnaeus, 1766), Epinephelus coioides (Hamilton, 1822), Pomadasys kaakan (Cuvier, 1830), Diagramma pictum (Thunberg 1792), Acanthopagrus cuvieri (Day 1875), Arius thalassinus (Rüppell, 1837), Carcharhinus sorrah (Müller & Henle, 1839), Rhynchobatusdjiddensis (Forsskal, 1775), Pastinachussephen (Forsskal, 1775). The grouper (Epinephelus coioides) and cobia (Rachycentron Canadum) were respectively accounted for the highest (24.19) and smallest (1.47) percentage of the fishing. Thisstudy reveals that thesize of fish and the depth have a positive relation ship.

Effect of garlic powder was surveyed on growth and hematological parameters of Huso huso in 2013 at Shahid Marjani Sturgeon Fish Propagation and Rearing Center, Gorgan. Experimental diets were provided with add of different levels of crude garlic powder (0, 1.5, 2 and 3%) in formulate diet. Fish with the average weight of 136.08 ± 0.7 g and average length of 33.43±0.2 cm were fed 3% of body weight daily for 4 weeks. At the end of experiment, biometry and blood sample collection carried out to assay hematological factors. Statistical analysis showed that body weight gain, specific growth rate and daily growth rate increased significantly in fish fed with diet containing 1.5% garlic compared to control group, also condition factor increased significantly in all fish fed with diets containing garlic in comparison with control group (P<0.05). Feed conversion ratio decreased significantly in fish fed with 1.5 % garlic compared to control group (P<0.05). Hematological factors (leukocytes count, hemoglobin, mean corpuscular hemoglobin and erythrocytes count) showed significant difference in all treatments in comparison with control group (P<0.05). The best response observed in fishes fed with diets containing 2% and 1.5% garlic.

The aim of this study was to estimate growth parameters of pike (Esox lucius) from Anzali and Amirkelayeh wetlands. In total, 272 and 148 specimens from Anzali and Amirkelayeh wetlands, respectively, were caught using fixed gill nets and fyke nets from November 2012 to June 2013. The age ranges were between 1+ and 7+ years for fish in both wetlands. Approximately, 74.53% of fish consisted of 3+ and 4+ years old fish. Additionally, Tmax calculated 23.08 and 21.43 for fish of Anzali and Amirkelayeh wetlands, respectively. Total length (TL) and weight (W) of pike ranged (20.4 to 71.3 cm) and (100 to 2635 g) in Anzali wetland and (19.2 to 73.6 cm) and (90 to 3140 g) in Amirkelayeh wetland. The b value of the length-weight relationship for fish of Anzali and Amirkelayeh wetlands ranged 2.782 and 2.856, respectively, indicating negative allometric growth (b<3, P<0.05). Relative weight (Wr) for pike in Anzali wetland (0.959±0.01) was differed significantly (P<0.05) compared with Amirkelayeh wetland (1.03±0.35). Instantaneous growth coefficient (G) was obtained 0.51 and 0.54 for pike in Anzali and Amirkelayeh wetlands, respectively. The von Bertalanffy growth parameter values were (L&infin;= 99.48 cm, K= 0.13 yr- and t0= -0.96 yr) and (L&infin;= 101.12 cm, K= 0.14 yr- and t0= -1yr) in Anzali and Amirkelayeh wetlands. Growth performance index ( f) was calculated 3.11 and 3.16 for fish of Anzali and Amirkelayeh wetlands. The weight of infinity (W&infin;) was estimated to be 8343.87 g and 9177.79 g for Anzali and Amirkelayeh pike. These results showed that environmental conditions are favorable for pike in Amirkelayeh wetland compared with in Anzali wetland.

This study aimed to identify the food items of Rutilus frisii kutum and the feeding intensity for this species was performed in the southern coast of the Caspian Sea.Sampling was carried out at 6 times from late March 2012 until late May 2013 in the distribution areas of kutum (less than 60 meter depths in the southern coast of the Caspian Sea) and 193 fish were studied for the contents of the digestive tract. The average total length and total weight of samples which were 36.9 ± 8.5 cm and 562.9±353.2 g, respectively. The results of this study showed that kutum are generally fed from Cerastorderma sp. and Balanus sp. as the presence frequency of Balanus sp. was more than Cerastorderma sp., but the amount of its consumption was less than Cerastorderma sp. In order of importance after the Bivalvia, Gastropoda, Crabs, Fish eggs, Filamentous algae were present in kutum GI. The feedingintensity and food strategy of this species are exposed to alter in term of gender, sampling periods and longitudinal length groups. Thus, the feedingintensity in males was more than females and the length groups in smaller than 30 cm was more than in higher length groups of 30 cm (P<0.05). Also the feeding intensity was shown in the different sampling periods as the reproductionperiods was drastically decreased with reducing temperature and in late winter. (P<0.05). At the recent survey, the results are indicated that the influence of adaptation and behavioral mechanisms, physiological and ecological, such as Bivalvia has a pivotal role for feeding of kutum, but the diversity amount on food consumption and feeding from Bivalvia were less than last years. If this species was surveyed in the southern coast of the Caspian Sea, it was appeared that this species was mostly fed on Cerastorderma sp., while it is recently demon strated the above prey was general food for kutum. It seems that releasing of fingerling kutum was mostly carried out by artificial propagation and its stock increasing was caused to decreasing frequency this food.