CASPIAN JOURNAL OF ENVIRONMENTAL SCIENCES (CJES)
Year:2015 | Volume:13 | Issue:2 |Papers Count:9

This study was conducted to examine morphometric and meristic characteristics alongside pigmentation patterns of bream larvae, Abramis brama orientalis, in four stages of larval development. Morphological characters including total length (TL), standard length (SL), notochord length (NL), head length (HL), head depth (HD), eye diameter (ED) and mouth width (MW) were examined from hatching time through 30 days after hatching (DAH). The re-sults showed morphometric variations in the different larval stages. Growth and development of fins occurred mainly at the Post Flexion stage with the completion of caudal fin at 9 mm TL and pelvic fin at 13.33 mm TL. At all larval stages, the highest concentration of pigments was seen on dorsal, ventral and somewhat on the lateral sides of body in descending order. The highest density of melanophores at larvae yolk sac stage was observed on the yolk sac and the back of head zone, while at preflexion and flexion stages melanophores were dominant on the back of head and on the skin folds which resulted from yolk absorption. At post flexion stage, high density of melanophores was found on the back of the head, bases of fins and caudal fin, while less concentrations of these cells were evident on the lateral sides of fish' body. In conclusion, a clear change in the growth and main morpho-logical characters were observed in postflexion stage. This may be due to the main development of fins, which would suggest enhanced swimming capabilities and also prey capture efficiencies.

This study was carried out to determine the effects of Immunogen as a prebiotic on growth-related parameters and gut micro-flora in R. frisii fry. A basal diet was formulated using common feed ingredients supplemented with Immunogen at 0, 1, 1.5, and 2 g.kg-1 leading to four experimental diets. Fish were randomly distributed in 500 L fiberglass tanks (1×1×0.5 m). The experiment lasted for eight weeks and the water temperature ranged between 21-24oC. R. frisii fry with an initial weight of 300 ± 1.7 mg and were randomly distributed in the experimental tanks. At the end of the experiment, growth performance, feed efficiency, and gut micro-flora were assessed. Results showed that inclusion of 1g.kg-1 Immunogen improved final weight, feed conversion efficiency (FCR), and specific growth rate (SGR) (p<0.01) in the fry. A larger survival rate of R. frisii fry was observed at 1 g kg-1 prebiotic inclusion level (p<0.01). However, body protein, fat, and ash were not influenced by prebiotic inclusion. Supple-mentation of 1 g.kg-1 prebiotic increased the total count of bacteria (p<0.05), but bacterial count did not change at 1.5 and 2 g.kg-1 prebiotic inclusion compared to control diet. In conclusion, Immunogen administration of 1 g. kg-1 is capable of improving the nutrients efficiency and performance of R. frisii fry through growth stimulation of beneficial intestinal bacteria.

Considering the increasing rice consumption in the world and also the excessive application of pesticides to increase production, an experiment was conducted to determine the pesticide residues and their effects on nitrogen, potassium and phosphorus content of Hashemi, Khazar and Gohar (SA13) rice cultivars, in a factorial design at randomized complete block design with three replications. In this study, rice plants were treated with three pesticides including insecticide Diazinon, herbicide Butachlor and fungicide Tricyclazole which are commonly used in the paddy fields of the southern coastline of the Caspian Sea, with standard concentrations recommended for these pesticides. The results indicated that the impacts of different pesticides on nitrogen, phosphorus and potassium contents in rice grains of Hashemi and Khazar cultivars were not significantly different. However, the nitrogen content reduced significantly in Gohar cultivar treated by Butachlor and Tricyclazole in comparison with control (p£0.01). Determination of pesticides residues showed that Diazinon residue in white grains of Hashemi, Khazar and Gohar cultivars was lower than recommended limit determined by Codex (0.1 ppm), and also Tricyclazole amount was below the limit of detection. Therefore, using pesticides in permissible limits is strongly recommended. However, it cannot be concluded that using pesticides; even in permissible limits, does not have dangerous impacts over time on living organisms of the Caspian ecosystem.

The reproductive biology of the Iranian cichlid, Iranocichla hormuzensis Coad, 1988, was investigated for 13 consecutive months in lower Mehran River, from August 2008 through August 2009. Four hundred and eighty six individuals (252 males and 234 females) were captured using a seine net (5 mm mesh size). The observed sex ratio was 1M: 0.93F (χ2, df=1, P=0.414). Mean ± SD of total length (TL) values in males and females were 70.34 ± 8.16 and 62.08 ± 6.51 mm, respectively. The frequency of 56-65 mm size class was higher in females and the 66-75 mm size class in males. A gonadosomatic index (GSI) analyses of females indicated that the reproductive period was during February-June, with a peak in March. Fecundity was best correlated with total body mass (M) (linear regression, r2=0.62) condition factor (linear regression, r2=0.62) and total length (TL) (linear regression, r2=0.56). The absolute fecundity ranged between 48-167 eggs with a Mean ± SD of 107 ± 35.2. Egg diameters ranged from 0.58 to 2.93 mm.

The effect of starvation and re-feeding was investigated on growth, hematology and biochemical parameters in juvenile Persian sturgeon (Acipenser persicus). Three hundred and seventyfive fish (108±0.63 g) were divided into five feeding groups. The control group (C) was fed to satiation three times a day during the experiment. The four groups were starved for 1 (W1), 2 (W2), 3 (W3), and 4 (W4) weeks respectively, and then fed to satiation during a 4 week re-feeding period. The results indicated that some parameters including final weight, specific growth rate, body weight increase, plasma enzymes (ALT, Alanine aminotransferase, AST, Aspartat aminotransferase and ALP, Alkaline phosphatase (hematological parameters [Mean corpuscular volume (MCV), mean corpuscular hemoglo-bin concentration (MCHC), and mean corpuscular hemoglobin (MCH)]were significantly affected by feeding regimes. The plasma cortisol, hematocrit, lymphocytes, neutrophils, eosinophils, and monocytes were not affected by starvation and subsequent re-feeding. These findings showed that short term starvations had no significant negative effects on growth performance, most biochemical and hematological parameters in Persian sturgeon couldrecover when re-feeding resumed.

Sediments from the Southern Caspian Sea, located in Iranian coast were examined on the basis of P-fractionation (five forms of phosphorus) by a sequential extraction scheme. Ninety-six surface sediment samples (for each season with triplicate) were collected from eight sampling transects in 10 and 100 m depths during summer and winter in 2010-2011. The result indicated that the most abundant forms of phosphorus were calcium bound phosphorus. Relative abundance of other forms of phosphorus follow the order: organic-P>Fe-P>Al-P>Absorbed-P. The loosely absorbed phosphorus represented<1% of the sedimentary inorganic phosphorus, while the Fe/Al phosphorus ranged 5–6%.The calcium bound phosphorus showed considerable contribution (88%) to the sedimentary inorganic P-loads.

One of the major problems about the chelant-enhanced phytoextraction is the potential metal leaching associated with chelant application. A glasshouse pot experiment was conducted to investigate phytoextraction efficiency of common reed (Phragmites australis (Cav.) Trin. ex Steudel) for Lead and Chromium and to determine EDTA (ethylenediaminetetraacetic acid) enhancement of the mobility and phytoextraction of Pb and Cr and the potential for leaching of metals during the phytoextraction process. The results revealed that the bioconcentration factors of underground organs of the plant species were relatively higher than the bioconcentration factors of shoots and metals concentrations in the plant organs decreased in the order of root› rhizome› leave› stem. Thus, P. australis would be applicable for Pb and Cr phytostabilization. Addition of EDTA (0, 2.5, 5, 10 mmol.kg-1) to polluted pots with Pb and Cr significantly enhanced the mobility of soil metals and led to elevated soil solution concentrations of Pb and Cr. Positive correlation coefficients were found between treatment time and heavy metals concentrations in the plant organs. Optimum phytoextraction was observed when 5mmol. kg-1 EDTA was added in single dosage, 60 days for Pb and double dosage for Cr, after the plant cultivation and, consequently, soil Pb and Cr concentration decreased with the passage of time. It can be concluded that P. australis can remediate Pb-Cr contaminated soils and EDTA had potential to promote the uptake of Pb and Cr for common reed, but with respect to its environmental leaching risk to ground waters, low dose should be used.

Common kilka Clupeonella cultriventris (Nordmann, 1840) is a brackish water and small pelagic fish species and is one of the most abundant fishes that live gregariously in the Caspian Sea. A total of 60 specimens of adult common kilka were sampled from two seasons. Fifteen pairs of microsatellites previously developed for A.sapidissima, C. pallasi, C.harengus, and S. pilchardus were tested for cross-species amplification on the common kilka. In this study, only five primer pairs were used successfully. Analyses revealed that the average of alleles per locus was 14.4. The average observed and expected heterozygosity was 0.153 and 0.888, respectively. All loci significantly deviated from H–W equilibrium. These results together with significant Rst. values for genotypic differences support the existence of different genetic populations along the Caspian Sea coast (Guilan Province).

Pomphorhynchus laevis is a common fish parasite in Europe which has been reported from Acipenser stellatus, Barbus capito, Barbus lacerta, Barbus mursa and Onchorhynchus mykiss in Iran. In a survey on the aquaculture potential of Gamasiab River in Hamedan Province, endemic fish parasites were investigated in summer and autumn 2008. After recording biometric characteristics, common necropsy and parasitology methods were used. Live acantho-cephalans were relaxed in distilled water at 4 ºC for 1 h and fixed in 10% hot buffered formalin. All specimens fixed in 10% formalin were stained with aqueous acetocarmine, dehydrated and mounted in Permount. The worms were identified using parasite identification keys. A total of 36 individuals of Chub, Squalius cephalus, were inves-tigated and 459 individuals of Pomphorhinchus laevis were recovered from intestine of 32 fish specimens. The prev-alence mean intensity and mean abundance of P. laevis were %88.9, 14.3 and 12.7, respectively. The maximum number of the parasite recorded in a five years old fish (403gr in weight) was 130 plerocercoids. Chub, Squalius cephalus, is reported for the first time as a new host record for P. laevis in Iran.