فصلنامه شیلات
سال شصت و ششم شماره 3 (پاییز 1392)

In this study the biological characteristics of fish Liza macrolepis was examined over a period of one year from November 2009 to October 2010 in the Musa estuary from Khuozestan province. In this regard، the 300 females’ fish Liza macrolepis were studied. Results showed the type of bag ovary of Liza macrolepis. In stage III oocyte diameter was measured between 483. 8 to 628. 5 µ with an average 579. 3±0. 2 µ. In stage IV، several groups of oocyte were visible and the ova diameter was measured between 435. 5 to 782. 7 µ with an average 648. 4±0. 4µ. In stage V، the ovules were visible in several groups and the ova diameter was measured between 746. 9 to 922. 4µ with an average 864. 6±0. 7µ. At this IV and V stages the ovules are due to accumulation of high levels of water has a certain transparency. The microscopic study of ovarian slices Liza macrolepis، the ovary during various stages of sexual development was studied and oogenesis obtained in 6 steps. Spawning In stage V in the months of April and May were visible.

Estuaries are one of the most productive aquatic ecosystems that both ecologically and economically are important. In estuarine ecosystems، zooplankton is very important group of animals that they are the basis for food web and intermediate steps in the planktonic food pyramid. Ecological studies، especially temporal and spatial variations of zooplankton are considerable in estuaries. The present study emphasized on zooplankton from Helleh River estuary، Busheher، Persian Gulf that composition، abundance، and biomass of zooplankton communities were investigated together with some of water characteristics. Samples were taken using plankton net with mesh size of 140 µm with vertical towing from 5 fixed-stations in mid-season from summer 2011 to spring 2012 for one year period. The zooplankton comprised of Arthropoda، Annelida، Protozoa، Mollusca، Echinodermata، Chordata، Rotatoria، Nematoda، Ctenophora، and Siphonophora. All samples were dominated by copepods، especially Acartia sp. In addition، Arthropoda had highest abundance while Echinodermata، Rotatoria، Nematoda، Rotatoria، and Ctenophora showed lowest abundance. Of Arthropoda، copepods with 10 genera including; Acartia، Euterpina، Oithona، Oncaea، Paracalanus،Corycaeus، Labidocera، Macrosetella، Microsetella، and Temora were at the highest abundance in zooplankton population. The maximum abundance and biomass was estimated at station estuary mouth (station 5) in all seasons، highest values in autumn (46051. 9 ind. /m3 and 165. 0 mg/m3) and lowest in winter (5388. 4 ind. /m3 and 20. 9 mg/m3). This study may be useful in understanding the ecological and biological processes for sustainable fisheries management in estuaries.

This study carried out in the Iranian waters of the Caspian Sea during 2009-2010، and aimed to determine species composition، relative abundance، and absolute abundance estimated of biomass. Research vessels using 9 m bottom trawl for depths less than 10 m and 24. 7 m bottom trawl for depths above 10 m. Trawling was conducted in 90 stations that were selected using a stratified random design. In each station، trawling carried out up to 30 minute and 2. 5-3 knot. In 2009 and 2010، 84 and 28 sturgeon fish were caught، respectively. Persian sturgeon was more than 83 to 100 percent of the catch. The mean total length of Persian sturgeon was 61. 9±28. 7 cm (spring) and 40. 5±27. 9 cm (autumn) in 2009. This value was 54. 7±23. 5 cm and 60. 2±17. 7 cm for spring and summer in 2010، respectively. Absolute abundance of sturgeon was estimated 1. 31 million fish in the Iranian waters of the Caspian Sea during spring but it increased to 3. 46 million fish in autumn 2009. Absolute abundance in 2010 was 831100 and 779200 fishes in spring and summer 2010، respectively. Biomass of sturgeon fish was 2019. 7 and 3014. 3 tons in spring and autumn 2009، respectively. These values were estimated 760. 6 tons (spring) and 855. 0 tons (summer) for the year 2010. The results show that Iranian fisheries organization policy in production and releasing of fingerlings has been unable to prevent the loss sturgeon stocks. Therefore، it seems the only way to recover their stocks is rebuild natural spawning areas، nursery grounds and preservation of them up to they reach commercial size.

Effects of various concentrations of egg white on texture، color، water holding capacity، viscosity and sensory evaluation properties of surimi prepared from common carp were investigated. Egg white powder was added at 1%، 2% and 3% to the surimi paste and mixed thoroughly، and then gels were stuffed into sausage casing and heated in a hot water bath at 90C for 30 min. The analysis resultant surimi gel indicated that applied additive improved the functional properties of common carp surimi. Addition of egg white powder caused significant difference (P<0. 05) in more indicators such as hardness، cohesiveness، adhesiveness، elasticity، etc at which was proportional to the egg white concentration. However، in terms of color، addition of higher concentration of egg white powder inversely reduced the whiteness of resultant surimi gel. The best score by panelists was advocated to the surimi with 3% egg white powder.

The environment of the Lavan Island has been suffered from the storage and production of crude oil، and also from ballast water. In contrast، the Hendourabi Island is away from the petroleum industries and hence ballasts water. Apparently، marine biota of the Hendourabi Island are less stressed that those from the Lavan Island. The present study investigated Zn، Mg، Fe and Cu in soft tissues of P. radiata، also examined the relationship between accumulation of metals and weight of the pearl oyster. Total weight، shell weight، and weight of the soft tissues were recorded. Concentrations of the metals of the soft tissues were measured using atomic absorption. There was no difference between specimens of the two Islands in Cu concentration of the soft tissues. However، there were significant differences between the specimens of the two islands in Fe، Mg and Zn. Also، there were significant differences in total weight and the weight of the soft tissues but not in shell weight. There was no relationship between metal concentration of the soft tissues and weight of shell and soft tissues in specimens from the Lavan Island but، in those from the Hendourabi Island، there was a relationship between Cu and Mg concentrations and weight of the shell and soft tissues. In conclusion، it seems that P. radiata from the Hendourabi Island are less stressed.

Nowadays aquatic with its high food value could attain a suitable place in family food shopping. Sea Cucumber is one of the important nurturing aquatic in the sea. These animals are nurturing in several countries such as India، Indonesia، Japan، Italy، and the United States because of having a high percentage of protein، Condroetin sulfate، Glycoside Saponin and also lacking of cholesterol. Unfortunately، there has not yet been regarded any considerable attention to these species of echinoderms in our country. This project considered many factors which are necessary for the nurturing of the Sea Cucumber. These factors include the place of farm، the time of nurturing، the amount of feeding، different types of Sea Cucumber nurturing methods، and estimating of costs. Stichopus Varigatus and Holothuria Leucospilota Sea Cucumbers have a high food and economic values. They are extensively found in Chabahar zone. There are several factors such as the extensive distribution of the mentioned species، their rather easy nurturing، fast growth in high distribution، and food consumption share with a low-cost make a qualified and good place for nurturing of this aquatic animal. Many attempts have been done in this study to fully operationally investigate the Sea Cucumber nurturing project in a farm of its nurturing in our honorable country in general and in Chabahar zone in particular. The results of the study demonstrate that the pay-back time in current project is one year and two months with a return rate of 75 percents which is totally economical.

Recently، due to the high costs and a decrease in producing of Lansy PZ، various researches have been paid attention to the baker''s yeast (Saccharomyces cerevisiae) as a substitute for Lansy PZ in Artemia cultures. In this study، the effects of six feeding regimes: Lansy PZ (as control)، enriched yeast with highly unsaturated fatty acids (HUFA)، enriched with HUFA and without mannoproteins in wall cells، yeast without mannoproteins in wall cells، industrial yeast 100% feeding regime and yeast 50% feeding regime in combination with the algae Dunaliella tertiolecta were examined on growth and survival of nauplii Instar I of two Artemia species (Artemia urmiana and A. franciscana) at a salinity of 80 part per thousands and a density of 500 nauplii per liter in laboratory cultures. Growth and survival of Artemia were determined in each group on 3، 7، 11 and 15 days after hatching. The two species of Artemia had the highest growth when fed Lansy PZ (P<0. 05). However، total length of A. urmiana (9. 09 mm) was higher than that of A. franciscana (7. 52 mm) when fed the Lansy PZ diet in 15th day. The two Artemia species had the higher survival rates when fed with yeast without mannoproteins (73. 20 and 75. 80%، respectively) than the Lansy PZ (60. 70 and 72. 07%، respectively) and other treatments. Our results revealed that the enrichment of the baker''s yeast with HUFAs and elimination of mannoproteins had a positive effect on survival rates comapred to growth of two Artemia species. However، the elimination of mannoproteins of yeast was a more suitable method in treatment of baker''s yeast as a diet for Artemia compared to other methods. Therefore، the yeast without mannoproteins treatment could be substituted with Lanzy PZ for Artemia feeding in different culture methods such as tanks or recirculated culture systems.

An experiment was conducted to determine the appropriate value of vitamin C on growth، survival، and Hepatosomatic Index (HSI) in Caspian brown trout (Salmo trutta caspius) fingerlings. Five diets containing 0، 50، 100، 200 and 400 mg kg-1 ascorbic acid were prepared as experimental treatments. Six hundred fish (9. 6±0. 6 gr) were divided into 5 groups with three replications each containing 40 fingerlings and fed by the respective diets for 9 weeks. Growth parameters including Final Weight (FW)، Protein Efficiency Rate (PER)، Weight Gain (WG)، Specific Growth Rate (SGR)، Feed Conversion Rate (FCR)، Condition Factor (CF)، and HSI were compared every 3 other weeks between the treatments. Fish sampling was done weeks. The results showed that survival rate of the fish in all experimental treatments was 100% and no sign of ascorbic acid deficiency such as gill deformities، abnormal swimming، and skeletal deformities including scoliosis and lordosis were observed in all Caspian brown trout fingerlings during the experiment. Also there was significant differences in FW، WG، SGR، PER، FCR، CF and HSI between experimental treatments (P<0. 05). The results showed that 200 mg kg-1 ascorbic acid were significantly increased the growth parameters of Caspian brown trout (P<0. 05)، although no significant differences were observed in fish growth rates between 200 and 400 mg ascorbic acid treatments. Therefore، findings of the present study illustrated that 200 mg ascorbic acid per kg diet is the optimum amount of vitamin C for the growth of Caspian brown trout fingerlings. According to the broken line model، the level of ascorbic acid for optimal weight gain was 248. 52 mg kg-1 diet.

The aim of current study was to determine the effects of different levels of betaine on growth performance، feeding efficiency and survival rate of Sander lucioperca larvae. The larvae (initial weight 1. 52±0. 06 mg) were weaned from day 12 post hatching (dph) with one of the six treatment which was commercial trout starter diet (Bio Optimal) and different levels betaine supplementation (0. 5، 1، 1. 5، 2 and 2. 5%) as well as a treatment that was feeding with live food (Artemianauplii) as control group. Trial lasted for 4 weeks (until 40 dph). The best final weight، Specific growth rate، final length and condition factor was obtained in control group (P<0. 05). Different levels of betaine supplementation had no significant effects on growth performance. Feed conversion ratio showed no significant difference between treatments، however food efficiency ratio was significantly higher in control group (P<0. 05). The highest survival rate and cannibalism was observed in control group while larvae fed artificial diet (i. e Bio Optimal and different levels of betaine supplementation) had 100% mortality after 33 dph. Results indicated that betaine supplementation did not improve growth and survival rate of S. lucioperca، and further studies regards weaning of pikeperch larvae are needed.

This study was carried out on 24 farmed Huso huso (8 males and 16 females) in the international Sturgeon Research Institute during 3 years. Samples were collected based on different sexual maturation stages. Results showed that hematocrit (PVC)، hemoglobin (Hb) and red blood cells (RBC) was more in males than females and increased in both them related to sexual development especially at stage IV. Mean corpuscular volume (MCV) and Mean corpuscular hemoglobin (MCH) showed no significant difference between males and females، but Mean corpuscular hemoglobin concentration (MCH) showed significant increase in males and females related to sex development. White blood cells (WBC) were lower significantly in males than females and showed no significant difference at different sexual stages. The most percentage of leucocytes belongs to lymphocyte، neutrophile، eozynophile and monocytes and increase with sexual development without significant difference. There was no basophile. Results of this study showed that blood indices profile in Huso huso was similar to others sturgeon species and some parameters were dependent on sex and sexual maturation stages.