فصلنامه بوم شناسی آبزیان
سال سوم شماره 4 (پیاپی 304، بهار 1393)

Considering the fact that fish biodiversity conservation and land uses planning¡ require reliable information about fish distribution and habitat use patterns In order to describe species habitat properties¡ habitat use and habitat selectivity indices are applied. Relative frequency and environmental variables¡ depth¡ width¡ slope of river¡ altitude¡ velocity¡ substrate¡ Overstream canopy closure and riparian vegetation type¡ were measured in 68 stations from upstream to downstream¡ to assess habitat properties of Iranial loach¡ Paracobitis iranica¡ in Kordan River.The habitat use and habitat selection ranges were achieved for each variable¡ considering habitat availability. Boulders¡ deciduous forest riparian vegetation type and 71-90% Overstream canopy closure¡ existed in selected habitat of this fish. The results of present study could help to identify habitat requirements of this endemic species.

The Iran’s coastal marine algae have great potential in the fields of medicine, food and cosmetics which unfortunately, fewer have been studied. In the present study, Total lipid and fatty acid profile of brown algae, N. zanardini were measured in both cold and warm season. The total lipid content with 41.1±0.8 mg/g dry weight was high in February. In the present study, Fatty acid composition of lipids showed that Palmtic acid (C16:0), in both seasons, was the main fatty acid, with 40.27±1.51% in June and 40.49±0.23% in February. In both season the amount of Arachidonic acid (AA) was higher than Eicosapentaenoic acid. Total saturated fatty acid (SFA) in tow season do not showed significant changes, while total monounsaturated fatty acid (MUFA) in July showed a lower amount and total polyunsaturated fatty acid (PUFA) increased in February. The ratio between omga6 to omga3 in both cold and warm season was: 1.14:1 and 1.50:1 respectively, which higher than the cold and temperate zones species. In general, the seaweed N.zanardini, collected in February has higher total lipid and polyunsaturated fatty acids in comparison with July, but the variation of fatty acid and total lipid in compared with temperate zones species is not so tangible.

The aim of this study was to investigate and estimate the CPUE (Catch Per Unit of Effort), CPUA (Catch Per Unit of Swept Area), biomass and length frequency of Threadfin Bream (Nemipterus japonicus) in Coastal waters of Bushehr. This study was carried out in March 2011. The study area was divided into three area (Northern, Central and Southern) and depth zones (10-20, 20-30 and 30-50 m) and stratified random sampling was used to collect data. The sampling data was collected from 41 stations. The forked length of Nemipterus japonicas was ranged from 14 to 29 cm and the average forked length was calculated 20.29±2.64. Total CPUE and biomass of Nemipterus japonicas were calculated 16259 tonnes and 1771 kg/hours, respectively. The minimum and maximum CPUE were observed in 20-30 m depth zone (169.1 kg/hours) and 30-50 depth zone (1370.8 kg/hours), respectively. Total CPUA of Nemipterus japonicus was calculated 19678.8 kg/nm2. The minimum and maximum CPUA were observed in 10-20 m depth zone with 4.1 kg/nm2 and 30-50 m depth zone with 2147.7 kg/nm2, respectively. The results showed that the most abundance of Nemipterus japonicus was in higher than 30 m depth zones in Bushehr waters.

In this study was investigated histipathological effects of Cd and As on liver of Aphanius sophiae. For this reason, 350 specimens were collected on 2011 from the Shoor River. For saltwater and separately freshwater treatment were designed seven treatments including the concentrations of 5, 10 and 20 for As 5, 10 and 20 for Cd and a control treatment in 30- L aquaria with three replicates. Twenty five specimens were introduced into each aquarium. After 18 days of exposure, three specimens were sampled from each treatment and fixed into Bouin solution and their liver were removed for histological preparation. The results showed that increasing the Cd and As concentrations in salt treatment increased hepatocyte necrosis and atrophy. The results in freshwater showed that with increasing concentrations cloudy swelling and atrophy were observed. The results indicated that the tissue destruction in As treatment more higher than in Cd, also, in freshwater was higher than in salt water. The losses rate of 11/4 time in fresh water confirmed these results.

Asian seabass (Lates calcarifer) is a potential candidate species for rearing in pond system in Iran because of its fast growth rate, ability to adapt to varying environmental conditions and its demand in domestic as well as export markets. Hence, growth parameters, survival and body composition of Asian seabass (20.70±0.36 g) was investigated. Experiment was conducted in three ponds In Choebde, Abadan with 3500 fish per pond. Diets were fed to fish five times daily until satiation for 135 days. Temperature and salinity were maintained at 27.36°C, 18.66 ppt respectively, while dissolved oxygen did not fall below 5.7 mg L−1. At the end of the trial, final weight 474.71±7.85 g, FCR 0.98±0.02, SGR 2.29±0.03, PER 2.30±0.05 % and survival 85% was obtained. Also, protein and lipid of body composition was 21.98±0.60 and 1.99±0.09 percent, respectively. Results show that Asian seabass can be ideal aquaculture candidate species in Khuzestan province.

Heavy metals are one of the most stable contaminants in water and unlike the other contaminants, degrade difficultly, accumulate in food chain and are considered an important threat to general health of humans. The process of biosorption, is a new technology to remove contaminants such as heavy metals based on microorganisms capability. Characterizing lead resistant bacteria in contaminated sediments of Persian Gulf in this study resulted in isolating a Micrococcus sp. as a lead resistant bacterium. Maximum growth of Micrococcus sp. in lead concentration of 50 mg/l, was 0.86 that reduced with increasing lead concentration however, it could grow up to a concentration of 800 mg/l. The optimum temperature was 25 °C for this bacterium and its maximum growth was significantly different in 15°C, 35°C and 45°C (P ≤ 0.05). The results of halophile test also showed that this bacterium is halo tolerant. Bacterial growth increased by increasing salt concentration from 0 to 4% but, when salt concentration reaches to 6, 8 and 10%, it decreased significantly.

Mohar pearl oyster Pinctada radiata is the dominant economic species of pearl oyster in the Persian Gulf, particularly along the Iranian coastal waters. As pearling has been banned since 2006, stocks of pearl oysters has not been investigated during these years. For this purpose, conditions of natural habitats and stocks of Mohar pearl oyster in its old catch sites were surveyed in the present study. Shallow waters around the Lavan island were searched through diving and two habitats of Mohar pearl oyster, namely Lavan No. 1 (Dardoor) and Lavan No. 2 (Hedabad), were detected. Area of Dardoor and Hedabad habitats was calculated equal to 60 and 15 ha, respectively and Mohar pearl oysters had the highest distribution in depth ranges of 7 to 12 m and 5 to 11 m, respectively. Total stocks of Dardoor and Hedabad habitats was surveyed about 357000 and 61500 pearl oysters of which 11% and 17% of oysters were catchable, respectively. Catch per unit of area in Dardoor and Hedabad habitats was estimated equal to 0.6 N/m2 and 0.4 N/m2 and catch per unit of effort was calculated equal to 119 N/hr and 82 N/hr, respectively. Biomass rate in these habitats was obtained equal to 4620 and 1163 kg, respectively. Results of this research revealed that the area, the amount of stocks and catch per unit of area of habitats has decrease in the recent years. Although the pearling has been banned in this region in the past seven years, restocking has been conducted slowly.

This study was performed to estimate the growth parameters and mortality rate of (Nemipterus japonicus Bloch, 1971) with using length frequency data in Bushehr fishing grounds. sampling did monthy with using cutlassfish pelagic trawl, gillnet and bottem trawl. The growth parameters of k and L∞ were estimated 0.79 y-1 and 31.5 cm respectively. The t0 was estimated -0.2. b quantity for this species equals to 2.71 which indicating the negative allometric growth model. W∞ quantity estimated about 390.07 g The exploitation rate (E) For this species was 0.31,with respect to fishing effort it is low and it shows that this stock has potential for more exploit too.