JOURNAL OF MARINE BIOLOGY
Year:2013 | Volume:5 | Issue:17|Papers Count:8

This study was carried out with the aim of examining the seasonal fecundity and developmental characteristics of the eggs of the female narrow-clawed Crayfish (Astacus leptodactylus) from Aras Dam Lake, Western-Azerbaijan during 2011. A positive correlation was found between both ovarian and pleopodal fecundity and female size. The mean value of ovarian eggs and Pleopodal fecundity was 206.55 and 129.5, respectively. Pleopodal fecundity was 37.3% lower than ovarian fecundity. The value of the gonadosomatic index (GSI) in females sampled on November was 13.53% (11.63-15.91%). The average size of pleopodal eggs diameter was 2.2 mm (1.07-6.59 mm). The number of eggs attached to 3rd and 4th pairs of pleopods was significantly higher than other pleopods. The egg number and gonadosomatic index increased significantly with female size (P<0.05). Histological analysis showed the ovarian oocytes of A.leptodactylus developed as asynchronous form.

Growth parameters, natural mortality and biomass of Cor Venus, Paphia cor were studied in Gassir, Bushehr shoreline areas (from 50o 40’ E and 29o 14’ N) during September 2008-2009. Samples were obtained at bimonthly from Gassir area in a year at low tide. Some transects were selected at random direction and at the zigzag pattern, so that cover all of the shell beds. In each transects one or two sampling quadrat (0.25 m2) was placed random. The length frequency of samples was measured bimonthly, from dextral to sinistral with vernier calipers to the nearest 0.1 millimeter. The length frequency was used to estimate growth and natural mortality parameters. Data analysis was conducted with the most recent version of LFDA statistical software. Stock abundance was estimated in the cold, temperate and hot months of the year. Salinity and water temperature were measured and averaged in the sampling months. Surface sediment samples (0-20 cm depth) were collected from sampling area inhabited by the P. cor. The Von Bertalanffy growth parameters for Paphia cor were estimated as K=0.8Year-1, L¥=55 mm and t0=-0.45. Estimated natural mortality rate for Paphia cor was M=0.57 and the maximum ages (Tmax) were calculated during 50 months. The mean of abundance of this species was 8.8±2.2 shells per quadrat and with a maximum in February (Bahman) and minimum in November (Abban). The mean of salinity and water temperature was 41.3 psu and 25.2oC, respectively. More than 88 percent of the bottom sediment in the studied area was included of silt (54.60%) and sands (32.74%). Present results show, two factors, temperature and sediment types affected on the growth and existing of P. cor in the studied area.

This study was carried out with the aim at the comparison of bioaccumulation capacity of nickel (Ni) and cadmium (Cd) in soft tissue such as muscle and gill and also two patch lengths (70±5 mm and 50±5 mm) of rock oyster (Sacostrea cucullata) in the coastal province of Bushehr (Deir port) in the winter 2012. Totally, 135 oysters were collected from three stations, In order to determine the concentration of heavy metals in their tissues.  Samples were transferred to the laboratory after biometry and isolating tissues. Concentrations of metals were measured using the Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS). Moreover, samples of the sediment taken from each station to analyze the heavy metals. The data analysis of ANOVA one-way and Duncans Multiple Range test revealed that the cadmium content of the samples of muscle and gill was higher than the nickel. There was significant differences (P<0.05) between the amount of cadmium and nickel. Cadmium average concentrations in samples of muscle and gill were reported as 2.53±0.45 and 6.87±0.41 ppm, respectively. The amount of nickel in muscle and gill were 0.76±0.64 and 1.09±0.42 ppm, respectively.  In addition, the biological absorption of nickel and cadmium by the larger oyster’s patch reported as 1.86±0.59 and 6.05±2.25 ppm; while the absorption of these metals by the smaller oyster’s group were calculated as 1.21±0.33 and 6.32±1.86 ppm, respectively. Thus, there were no significant differences (P>0.05) between the amount of cadmium and nickel in two patch lengths of rock oyster. The mean concentrations of Cd and Ni on sediment samples collected from three stations, reported as 1.43±0.86 and 1.37±1.11 ppm and showed no significant differences (P>0.05) between the amount of Cd and Ni in samples.

Twelve Scomberoides commersonnianus with mean weight 30±0.63 kg were caught from Larak Island (Persian Gulf). Samples were divided into three groups, and the muscle samples were taken, being homogenized completely and transferred to laboratory using ice for chemical analysis. This study was evaluated the nutritive value of Talang queen (Scomberoides commersonnianus), as one of the valuable constituents in man’s diet, caught from coastal waters of Larak Island, in Persian Gulf. Crude protein, crude lipid and moisture content of tested specimens were found 20±0.85%, 6.32±0.42% and 71.44±0.19% (wet weight), respectively. The results of this study showed that meat of Talang queen is a good source for both essential amino acids and essential fatty acids. The major amino acid detected were glutamic acid, lysine, lucine, aspartic acid and valine with the percentages 5.9 mg/g, 5.8 mg/g, 4.8 mg/g, 4.6 mg/g and 3.6 mg/g, respectively. Total unsaturated fatty acids were determined as the major constituent (54.47%) of the whole lipid content. The dominant unsaturated fatty acids were oleic acid, docosahexanoic acid, ecosaterianoic acid and ecosapantanoic acid with the mean of 21.4±0.55%، 11.12±0.62%، 3.35±0.18% and 3.3±0.13%, respectively. The dominant saturated fatty acids were palmitic acid and estearic acid with the mean of 36.32±1.24%, 8.66±0.59%, respectively. The content of unsaturated fatty acids belongs to w3 (17.09%), ω6 (6.44%) and w9 (21.4%) were measured. Thus, Talang queen fillet could be considered and introduced as a valuable source of food for consumers and fishing industry and dieticians.

One of the most essential information on fisheries stock sssessment models, as is knowledge of the coefficients of the length-weight relationship. Captures were made during the years 2003 to 2007. The parameters a and b of the equation W=aLb were estimated. The parameter b ranged from 2.705 to 2.764, which indicated that the weight growth is isometric. The results showed a significant relationship between changes in the coefficients a and b.

Among the pollutants in aquatic ecosystems, heavy metals are considered dangerous pollutants due to their toxic effects and bioaccumulation in organisms. They can cause chronic and acute poisoning when consumed by human. Mercury is one of the most toxic metals, which can accumulate in a food chain and in the most top of it, the human body. In this study concentrations of mercury were measured in four species of aquatic organisms, black pomfret, white Indian prawn, white leg shrimp and crayfish and the consumption risk assessment for each of these seafood species were assessed. Samples were obtained from Tehran market and the muscles of species were dissected and wet digested. The concentrations of mercury in solutions were determined using cold vapor technique and atomic absorption spectroscopy. The average concentrations of mercury in muscle of the species were 0.331, 0.323, 0.346 and 0.113 mg g-1 wet weight, respectively. These concentrations were within standard levels determined by the international organizations such as WHO, FAO, EPA, FDA, EC and MAFF. HQ index was below 1 for all species. Therefore, the consumption of these seafood species is not a serious threat to the consumer’s health in terms of mercury concentration.

This study was conducted to determine macronutrient concentrations of water and molar ratios of them at four transects (Tonekabon, Nowshahr, Babolsar and Amirabad) in the southern of Caspian Sea- Mazandaran Province in 2012-2013. Seventy two surface water samples were collected at 5, 15 and 30 meter depth and macronutrient concentrations were analyzed using standard methods. Results showed that minimum, maximum and mean (±SE) cocentration of dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and disoolved silicon (DSi) were registered 2.44-10.92 (5.89±0.21), 0.23-1.80 (0.58±0.04) and 5.30-15.12 (9.50±0.20) mM, respectively. In addition, annual mean (±SE) molar ratios of DIN/DIP, DSi/DIP and DSi/DIN were obtained 12.49±0.86, 18.82±0.78 and 1.75±0.07, respectively. Results of current study also showed that trend of the molar ratios of DIN/DIP and DSi/DIP were declined from May (2012) to March (2013) with increasing of DIP and DSi concentrations and decreasing of DIN concentration. In a conclusion, the molar ratios of macronutrients and the corresponding curves, the system was phosphorus limiting factor for phytoplankton during May and June but in December, January and February tend to be found towards nitrogen limitation and in September, system has experienced both  limiting factor (P-limiting and N-limiting). There was no Si-limitation for phytoplankton growth at all regions and months in this area.

This study was done to investigate the effect of different levels of dietary prebiotic yeast cell wall on microflora of intestine in farmed great sturgeon fingerlings (Huso huso) during 8 weeks. After acclimatization to rearing conditions and basal diet for one week, 60 farmed great sturgeon fingerlings with mean weight 35.69±0.36 g were distributed into 12 aquaria (with dimensions 50´45´40 cm) in 4 treatments (0% as control, 1%, 1.5% and 2%) in three replicates (completely randomized design) and kept at a density of 5 fish per each aquarium. At the end of trial, microbial index, total viable count and lactic acid bacteria in intestine and faeces were examined. Results showed that there were significant differences in fish fed with the level of 1.5% prebiotic between treated fish from viewpoint of total bacterial count in TSA and MRS in intestine 5.74±0.03 and TSA and MRS in faeces 9.04±0.77 in compared to control (P<0.05). As a conclusion, this prebiotic at the level of 1.5% can improve intestinal microflora of great sturgeon.