فصلنامه محیط زیست جانوری
سال یکم شماره 2 (تابستان 1388)

Crocodylus Palustris is the native species of Iran (Sistan–Baluchestan province) on which no research in the field of physiology has been conducted to date. In the present research, experiments were performed on the unic parameters (Na, K, Ca, Cl, Mg) of the Crocodylus Palustris blood residing in Sistan–Baluchestan province. For this reason, 12 numbers of crocodiles which were in captivity under similar experimental condiyions were selected and their blood samples collected.During the research, the experimental conditions involving the residence, protection, temperature, made of nutrition, and the procedure of blood sampling of the crocodiles were controlled and like wise similar. All the crocodiles were subjected to bioevaluation and wean while their weight, length and other related characteristics were recorded.Results showed that among the ions calculated, sodium ion with a variation coefficient of o.4 percent and magnesium ion with a variation coefficient of 7.7 percent respectively, have a very small variance and a large variance which are independent of body weight. Calcium ion did not show significant correlate except with chloride ion and has a large and reversed correlation with magnesium ion at the level of one percent. Calcium ion also has a significant and linear correlate with sodium and potassium ions at the level 1 percent. Potassium ion has reversed correlate only with magnesium ion at the level of 1 percent.On another hand, potassium ion has a significant correlate with sodium ion at the level of 1 percent, which is linear. But potassium ion does not show significant correlate only with chloride ion and showed significant and reversed correlate with other characteristics at the level of 1 percent. Chloride ion also displays no significant correlation with sodium ion.

This study was conducted on coastal waters of Golestan province in 2004. The relationship between body weight–fork length and Age–fork length for all samples were obtained: W= 1.5 × 10-3 FL 2.1200, (r = 0.8210) and FL = 139.630, Age0.3372, (r = 0.8313).In this research growth formula and its parameters was estimated: Lt = 33.48[1-exp-0.250 (t + 0.378)], L = 33.48cm, k = 0.250, to = -0.378.The average of condition factor for male and female were obtained 1.256±0.2640 and 1.033±0.2456, respectively. Samples were at 7 different age classes (2-8 years) and the most fish numbers (51.30%) which involved were 3 and 4 years old. 77.45% of samples were female and 22.54% of them were male so sexual–ratio was obtained: 1:3.53 (male:female). GSI peak for female at first of forth week in April was (21.8345) and male at the end of third week in March was (8.2720). The Minimum, maximum and mean of absolute fecundity were estimated: 4239, 85187, 20891 ova, respectively.

Bisexual Artemia in Urmia lake is a native species that is very important in biodiversity and phylogeny aspects. In this paper, effect of salinity on reproduction model of Artemia urmiana from 1995 till 2002 were studied. Urmia lake water salinity was increased affected from low precipitation in recent drought years, in november of 2001 it became more than 300ppt and transparency of water in some stations were maseaured as their depth. In sampling it was determined, in natural condition, same as artificial condition, some stresses such as high salinity and reduction in food availabe, shifted reproduction model of Artemia from ovovivipariety to ovipariety.According to data analysis there are significant differences (P<0.05) between two groups of salinity, less and more than 172ppt and oviparous percentages of Artemia urmiana.

Otolithes ruber (Teleostei: Sciaenidae) is an important species in the Khouzestan province waters, Iran. Catch management of this species in region is required to be known some biological parameters such as growth and mortality. We used commercial fishing data and samples in the Choebdah and Hendijan landing near Abadan port to estimate population dynamic parameters for O. ruber. The population parameters were analyzed using the FAO-ICLARM stock assessment tool (FiSAT). The growth parameters of von Bertalanffy equation were as, L∞: 69.72cm, K: 0.53year-1 and t0: -0.16. The estimated value of total mortality, natural mortality and fishing mortality were 2.25, 0.84 and 1.41year-1, respectively. Exploitation ratio, E was estimated to be 0.63 year-1 and these high values of E indicated that the Otolithes ruber stock in the region waters is under fishing pressure

In this survey, 50 brooder Indian white shrimp (Penaeus indicus) caught from Jask area in the Persian Gulf. After freezing specimens, transferred them to laboratory and investigated for parasitic nematode and they were visibled with eye. Nematodes, separated from remainder gut contents, then coloration and fixed by the help of light microscope and acquaintace keys. They were identified to genus level. The genus of nematode was Hysterothy lacuim. For statistical study we used (One way ANOVA) and SPSS software. From 50 samples that experimented in this test in 27 cases nematodes observed. The result indicated that in 54 present of all breeders nematode parasitic was observed.

Understanding the quality & biological conditions of aquatic ecosystem is essential for management. In this study, some indices (Temperature & Dissolved Oxygen) of Shahrestanak River (Karaj, Iran) were measured and Hillsenhoff Index (HFBI) was used. This research was carried out from January 2006 for duration of one year in 3 stations of the river with 3 replication for temperature and dissolved oxygen sampling and at the same time different types of macroinvertebrates of the river was sampled. Dissolved oxygen in the River was varied from maximum 13.3mg/l in November to 6.8mg/l in July. The average was 8.3mg/l in this time. The maximum temperature was 12°C in July and minimum was 4.3°C in December. The total average was 7.7°C. In this study, 21 families of macroinvertebrates were identified. Due to seasonal variation, maximum & minimum number of macroinvertebrate sample in winter was belonging to Baetidae and Tabannidae families, respectively. In spring Chironomidae and Stratiomyidae; in summer Chironomidae & Gammaridae families and in autumn Chironomidae and Tabannidae families respectively had maximum & minimum number of macroinvertebrates. The maximum number of abundance was 1575samples/m² which belonged to Chironomidae and the minimum number was 1samples/m² which belonged to Stratiomyidae. The value of Hillsenhoff Index in sampling period was 3.39 to 5.1 and the average was 4.56 which according to the table of Hillsenhoff Index is a cue to the good quality of water during the year of sampling.

In this study, post larvae were fed with different level of Artemia franciscana nauplii replacement (0%, 50%, 100%) with microdiet. Post-larvae were fed with experimental treatments from (PL1) stage to (PL11) stage. The results have shown that partial or complete replacement of live food with microdiet significantly decrease survival, total length, carapace length, weight and the number of spine over the rostrum of post-larvae (P<0.05). However, substitution of live food with microdiet had no negative effects on resistance to salinity stress (P>0.05). According to these using commercial microdiet is not a proper replacement for live food in post-larva culture and still there is a need for further studies regards nutritional requirement of shrimp larvae and post-larvae and diet manufacturing process.