A study on length frequency, length-weight relationship, distribution and biomass of shrimp (Palaemon adspersus) in the south east Caspian Sea, Golestan Province

Assessment of length frequency, length-weight relationship, distribution and biomass of the shrimp P. adspersus was done four times in the summer of the year 2002 in the Gorgan Bay and south east of the Caspian Sea. Results indicated that the mean carapace length (CL) was 13.55±1.79mm, and minimum and maximum CL was 8.7 and 18.7mm respectively. We determined the length weight 123 relationship as W=0.0035CL^2.3123 In the south east region of the sampling area the mean carapace length was 12.67±2.23mm and minimum and maximum CL was 5.2 and 17.5mm Respectively. For this region, we found the length weight relationship as W=0.0072CL^2.0956 P. adspersus were found in all depths. Parallel with the air temperature increase, the shrimp density showed an increase at the depth of 2-10m. The estimated biomass of this species in the Gorgan Bay was 1999kg and in the south east region was 1160kg

Ecological study on fisheries important rivers and bays in the south part of the Caspian Sea 2nd phase: Gorgan Bay

In this study ichthyoplankton, phytoplankton, zooplankton, benthic and hydrochemistry parameters were studied. 9 out of 11 sampling stations were in the Gorgan Bay area and 2 of them were in the mouth of the Bay. Ichthyoplankton survey were carried out in 6 stations and the other surveys such as phytoplankton, etc were done in 11 stations in 2009. Gorgan Bay map and position of sampling sites are given at the end of material and methods section. Biomass and frequency of phytoplankton at different stations, months and seasons were calculated that are presented in Tables 1 to 3. Hydro-chemical parameters such as water temperature, air temperature, visibility, DO, BOD5, pH, Alkalinity (bicarbonate, carbonate and total), Hardness (calcium, magnesium), CL,EC, Salinity, N (nitrate, nitrite, NH_3), Phosphate were measured and results are shown Table 11. Biomass (mgr/m^3) and numbers (ind./m^3) of 47 genus of different phylum of phytoplanktons such as Cyanophyta, Chlorophyta, Pyrophyta, Chrysophyta and Euglenaphyta as well as different phylum of zooplanktons consist of Protozoa, Arthropoda, Rotifera and Cyliophora were estimated. Frequency of phytoplanktons (ind/m^3) was 131.2, 1.6, 65.3, 18.9 and 23.8 million respectively. Furthermore, their biomass was 308.4, 1.9, 1358.9, 295.1 and 124.7 mg/m^3, respectively. The maximum and minimum numbers were observed in Leptolingbaya belonged to Cyanophyta and Diatoms of Chrysophyta 84.3 and 0.025 million (ind/ m^3) respectively. The maximum and minimum biomass was observed in Gyrosigma (Chrysophyta) and Tetradron (Chloropyta), 12317.3 and 0.014 mg/m3 respectively. The average biomass of zooplankton was measured 531.74, 30.77, 225.07, and 96.26 mg/m^3 respectively and the total was attained 883.83 mg/m3 Table 5. The maximum and minimum biomass of all zooplanktons was estimated in November and July, 3446.23 and 6 mg/m^3 respectively. Furthermore, the maximum and minimum numbers of zooplanktons were found in September and July which were 48.4 and 0.002 millions respectively and the average number was 8.4 ind/m^3 Table 4. Also numbers and biomass (gr/m^2) of 11 families of benthos which inhabit Gorgan Bay such as Annelida, Mollusca and Arthropoda were investigated in separated stations and distinctive months. The maximum and minimum biomass of benthos was observed in January (42.91 gr/m^2) and March (0.6428 gr/m^2). The biomass was considerable in April, February, August and December (Tables: 4, 5 and 6)

Investigation on the possibility of artificial propagation, cultivation and brood stock management of Vannamei shrimp

Project was carried out at the Gomishan Centre for training and education which is located 15 km far from Gomishan City in the Golestan Province. Prebroodstocks were chosen from ponds (stocking density: 3/m^2). 860 male and 890 female broodstocks were separated and transferred into greenhouse (400 m^2). The average growth rate per day was 0.3 g and survival rate was 90%. After reaching 42 g in males and 52 g in females they were ready for Eyes stalk Brood stocks were transferred into propagation hall in June and after a week females gone under Eyes stalk. 10,890,000 eggs were yielded from 50 females and consequently 7, 187, 0.50 nauplius were produced. Each broodstock spawned 1.34 Times. The maximum hatching was 75% that in was average 64.2%. Mass of Cetocerous Algae was mass produced to be fed for post larvae. Finally 35,000 PL15 were yielded. PL15 were transferred into two half hectare and one 1 ha ponds in July. The stocking density was 18 PL/m^2. Biometric parameters together with air and water temperatures, and pH were recorded daily. Results indicate that the maximum survival rate was 58% (pond No. 5) and minimum was 52% (pond No. 17). The average weight after 101 days cultivating was 23 g which is appropriate. Also the average daily growth rate was 0.2g and the FCR was 1