The influence of colored light and tank color was investigated on growth performance (body weight, growth rate, carcass composition, etc.) and physiological status (blood and plasma parameters) of beluga (Huso huso) juveniles. The study was conducted using 64 specimens for colored light treatments with initial weight 98.83 ± 1.42 (mean ± SE) g which were reared under white, red, green and blue light and using 80 specimens for tank color treatments with initial weight 98.50 ± 1.24 (mean ± SE) g which were reared in white, red, green, black and blue tanks, all for 12 weeks. Red light had a significantly negative impact on beluga growth performance (in contrast with blue light) accompanied with reduced liver total lipids and plasma albumin and elevated plasma cortisol, glucose, cholesterol and triglyceride (in contrast with the other treatments). No significant effects of tank color were detected on growth performance. Nevertheless, most of growth parameters suggested a positive impact of black tank. Although plasma glucose levels in white tank were significantly higher than the other tank colors, no significant effects of tank color were detected for the other physiological parameters. Therefore, based on the obtained results, blue light by establishing comfort in beluga juveniles spelled increased growth performance and had positive significant effect on physiological conditions. Moreover, taking into consideration the consistency of all growth parameters among beluga juveniles reared in black tanks, it is suggested that considerable results in regard to this treatment may be achieved if the rearing period prolongs.

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Because the sex of sturgeon cannot be determined externally until the pre-spawning phase, they are currently sexed by means of minor surgery. Although the survival rate is nearly 100%, this surgery is invasive. One effective solution is to use DNA markers to diagnose the sex. In this study we employed bulked segregant analysis methodology to screen for genetic markers associated with the sex of the beluga (Huso huso). DNA bulks (male and female) were created by combining equal amounts of genomic DNA from 10 fish of both sexes. A total of 310 randomly amplified polymorphic DNA primers was used to screen the bulks, resulting in 4146 bands that were present in both sexes. Our results suggest that either the sexspecific DNA in sturgeon may be comprised of sequences not complementary to 310 random decamer primers or that sex chromosomes are weakly differentiated in the sturgeon genome.

The Caspian Sea, the largest inland closed water body in the world, has numerous endemic species. The Caspian brown trout (Salmo trutta caspius) is considered as endangered according to IUCN criteria. Information on phylogeography and genetic structure is crucial for appropriate management of genetic resources. In spite of the huge number of studies carried out in the Salmo trutta species complex across its distribution range, very few data are available on these issues for S. trutta within the Caspian Sea. Mitochondrial (mtDNA control region) and nuclear (major ribosomal DNA internal transcribed spacer 1, ITS-1, and ten microsatellite loci) molecular markers were used to study the phylogeography, genetic structure, and current captive breeding strategies for reinforcement of Caspian trout in North Iranian rivers. Our results confirmed the presence of Salmo trutta caspius in this region. Phylogenetic analysis demonstrated its membership to the brown trout Danubian (DA) lineage. Genetic diversity of Caspian brown trout in Iranian Rivers is comparable to the levels usually observed in sustainable anadromous European brown trout populations. Microsatellite data suggested two main clusters connected by gene flow among river basins likely by anadromous fish. No genetic differences were detected between the hatchery sample and the remaining wild populations. While the current hatchery program has not produced detectable genetic changes in the wild populations, conservation strategies prioritizing habitat improvement and recovering natural spawning areas for enhancing wild populations are emphasized.

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The influence of short-term storage (3, 6 and 9 h) of Persian sturgeon (Acipenser presicus) ova outside the ovary (ex situ storage) in coelomic fluid and PSACF (Persian Sturgeon Artificial Coelomic Fluid) medium was studied at (4°C and 18°C). One mature female and three mature males were selected for gamete collection and fertilization, as well as 18 females were sampled for coelomic fluid collection. Fish were intramuscularly injected with acetone-dried sturgeon pituitary and their ova and milt collected according to common spawning methods. Thereafter ova were filtered and coelomic fluid was separated for further using in experiment on ova storage. For mimicking of ovarian fluid and designing the PSACF medium, chemical composition of ovarian fluid from 18 females was analyzed separately in 26 samples and osmolarity and pH for each sample were determined and the PSACF medium was formulated.This experiment was done with 12 treatments in 3 replicate using four factor combinations. For each treatment 5 cc (about 300) ova were used. After storage for 3, 6 and 9 h in the two test temperature, ova were fertilized with pooled sperm and then transferred to Yoshchenko incubators. Fertilization rate, hatching rate and percentage of malformed larvae were determined.Storag period and storage medium had significant effect, on fertilization rate, hatching success and malformation of larvae (P<0.05). Also, temperature had significant effects on fertilization rate (P<0.05) but no significant effects on rate of hatching and number of malformed larvae (P 0.05). Fertilization and hatching rates decreased with time (3, 6 and 9 hours of storage prior to fertilization). Malformation rates in hatched larvae increased compared to the controls. Interactions between time of storage and storage medium and temperature and the resulting effects on fertilization, hatching and malformation rates were significant (P<0.05).Using a prepared PSACF medium at 18ºC for 3 h resulted in 80.33% fertilization rate, 70.5% hatching rate and 2.6% malformation rate in newly hatched Persian sturgeon larvae.

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