JOURNAL OF MARINE BIOLOGY
Year:2011 | Volume:2 | Issue:8|Papers Count:9

Sea surface temperature is considered as an important climatic index and Chlorophyll a concentration is regarded as an essential factor for sea phytoplankton biomass and productivity for marine ecosystem. Caspian Sea is known as one of the best marine ecosystem in the Earth. In order to assessment of problems and threats of Caspian Sea, it is necessary to monitor sea surface temperature and Chlorophyll a. This study attempted to investigate time series of sea surface temperature and Chlorophyll a in monthly and seasonal scales and analysis the temporal correlation of sea surface temperature with Chlorophyll a. Hence, MODIS images of Terra and Aqua satellite were gathered from January 2003 to December 2009 over Caspian Sea. After doing of image preprocessing, the algorithms of sea surface temperature and Chlorophyll a were performed on the images. And then, monthly time series of sea surface temperature and Chlorophyll a were done. The result of seasonal Man-Kendall showed that there is a rising trend in amount of Chlorophyll a concentration and a lack of trend in sea surface temperature. In addition, the monthly and the seasonal pattern of Chlorophyll a are based on sea surface temperature. This is a significant change in Chlorophyll a concentration based on Pettit’s test in mid-2006. The results of this study indicate that there is a positive correlation between Chlorophyll a and sea surface temperature in the period of study. So that, 65% of Chlorophyll a concentration is justified as a dependent variable with sea surface temperature by using linear regression model. Also, Fisher’s F test confirms this significance of relationship.

In this Study, 186 pieces of Brown trout, salmo trutta fario were captured monthly from June to December 2005 with drift gill net from the Lar reservoir. The age of samples varied between 2 to 5 years with a mean of 3.0±0.7. Average of fork length and weight respectively were 27.5±6.0 cm and 235.1±124.0 gr. Index of fullness average was 148.2±85.9 that indicates an undesirable status of fish feeding. Average of relative length of gut was 0.47±0.08 and condition factor were determined 0.91±0.14. Gut contents of Brown trout in this lake included Daphniidae, Chironomidae and Cytheridae families with following percentages respectively 63.970, 17.981 and 13.034 which were the main preys of the fish. Although Tubificidae with 77.12% were the most frequent benthos organisms but their frequency in the digestive system of fish was 0.002% which showed fish reluctancy for consuming them. In addition to cannibalism, a wide range of macrobenthic invertebrates including aquatic insects, terrestrial organisms and mollusks of the Limnaeidae family were identified in fish diet.The results of this research indicated that Brown trout consumed a wide range of organisms belonging to the river ecosystem in addition to lake organisms in their natural diet that was due to frequent movement of fish between two ecosystems.

In order to estimate the by-catch of demersal in a part of Khuzestan coastal waters (North West Persian Gulf), a sea Survey was carried out by using research ship. Study area was divided to three strata (khore Musa, Baherkan and Life-boseif) and 164 stations were selected randomly and were ampled by swept area method.25, 29 and 28 species were identified in these substrata respectively. Mean catch per unit area and bycatch in Musa khore, Baherkan and Life-bosif were 3343 (kg/nm), 4928 (kg/nm), 5467 (kg/nm) and 2885 (kg/nm), 4029 (kg/nm), 4860 (kg/nm) respectively. Cynogloss arel (14.74%) and Scomberoides commersonnianus (0.3%) were maximum and minimum biomass species respectively. Mean bycatch value and ratio between bycatch to total catch in these areas were estimated 3924.73 (kg/nm) and 0.44 respectively.

The aim of the present study is estimation of the growth parameters of anchovy kilka (Clupeonella engrauliformis Svetovidov, 1941) in the southern Caspian Sea. In this study which was conducted during 2010, the samples were provided from Babolsar fishing harbor in Mazandaran province. In the laboratory, the measurements were done and samples were sorted into length and weight size bins. Age was determined using sagitta otoliths. The results were compared with the previous years. The mean length and weight of fish were 116.78±16.5 mm and 12.59±4.2 g, respectively, which has increased in comparison with the previous years. The growth parameters for females were (L∞=138.7 mm, k=0.55 yr-1, t0=-0.42 yr) and for males were (L∞=160.5 mm, k=0.25yr-1, t0=-0.92yr). Length-weight relationship in females was w=0.00008 FL2.50 (R2=0.902) and in males was w=0.00007 FL2.50 (R2=0.921) which have an allometric growth pattern. Age composition of females was constituted of 6 age groups, including 2-7 years. For males, this was constituted of 7 age groups, including 1-7 years. Mean age of females and males were 4.58±1.43 and 3.86±1.62 years, respectively. In this species population, 4 years old fish were dominant with relative abundance 26.55 percent. Results showed that in recent years, anchovy kilka population has been older and its length and weight has increased. These changes can be due to the weak stock reconstruction process which has affected by invader ctenophore and over-fishing.

Following three concentration of Aloe vera crude extract in commercial food, 0.1%, 0.5% and 1%, were prepared and each concentration were fed to triplicate groups of Amphilophus labiatus for 60 days. Control groups were fed with Aloe free diet. At the end of treatment growth factors and mortality rate were calculated and 10 fish in each group were challenged with A.hydrophila and after challenge mortality was recorded for 10 days. Results showed that administration of 0.5% and 1% Aloe supplemented feed to A. labiatus increased growth rate, food conversion rate (FCR) and specific growth rate (SGR) compared to control (P<0.05). Feeding with 0.1% Aloe supplemented feed had no significant change on growth factors of fish (P>0.05). Although after challenge mortality were reduced in fish fed with 0.5% and 1% Aloe supplemented food (P<0.05), no significant reduction in mortality after challenge were recorded in group fed with 0.1% Aloe supplemented food. It can be concluded that the best concentration of Aloe vera crude extract for promotion of growth and bacterial infection resistance was 0.5%.

Sonbolrood river originates from the springs of Kalij village mountains located in Savadkooh region in geographical situations of N: 36" 18' 877 and E: 52" 49' 384, and finally, joins Babolrood river, which is one of input branches of south basin of the Caspian Sea. Geographical situation of this region is N: 36" 20' 15 and E: 50" 24' 550. Sonbolrood River located in Savadkooh region was assessed with the aim of a better understanding of benthic invertebrates' roles in self- biofiltration resulting from sewage entrance. Consequently, 4 stations were selected among 8 stations according to the pre-sampling program. Sampling started in autumn 2009 and ended in summer 2010.Generally, Sonbolrood river benthoses consisted of 3 branches of arthropods and wide worms along with 3 classes, 6 orders and 14 families of mollusca. The maximum diversity and distribution were in autumn and the minimum were in summer at all the stations.The fourth and the third stations showed the maximum and the minimum diversity and distribution. The water quality of Sonbolrood river was assessed for all the stations except station 3, based on Hisenov water quality guideline. Sonbolrood river was a wholly decent ecosystem for aquatic organisms due to having an extreme steep, stony-sandy bed and doing self-biofiltration. The increase of organic substances and the sewage of the factory located in an industrial complex at station 3, the increase of water contamination resulting from culturing warm-water fish in the soil dam of Sonbolrood river and the entrance of the adjacent village home sewage such as Seyedkala village and Sirdarkala, caused the increase of pollution and trophy of the benthoses resistant to the pollution and influenced on benthic communities.

In this project, we studied effects of nanosilver on growth rate and reproduction of (Anabaena flos-aquae) for 3 month period (of 2010) in Inland Water Aquaculture Research Center, Bandar-e-Anzali. The algal cultures by purified stock of Anabaena flos-aquae were maintained 6 treatments with control and Zinder media with different concentration of nanosilver by triplicate under laboratory conditions (Temp. 25±2oC, Light 3500±350 Lux) for 96 hours. In the next stage we measured amounts of absorption in 750 nm by spectrophotometer. And then we count the number of algae at the beginning and the end of experiment by a thoma slide. Therefore we measured scale of Chlorophyll a with Millipore set and perused to mg/L of Chlorophyll. It was found effective concentration range for this material was 0.005–0.05 mg/L in Anabaena flos-aquae and the effective quantity of nanosilver, for providing the maximum growth Anabaena is 0.005 mg/L. This experiment shows us the growth rate and reproduction of Anabaena in mentioned concentration has the best result were as higher concentration can create a negative effect on the growth rate and reproduction of Anabaena.

In this study the effect of five experimental diets and iso nitrogenic and iso energic with different protein sources with 4 replications for each treatment of narrow claw crayfish in a total of 15 aquariums in the form of a completely randomized design were evaluated. The main sources of supply of fish protein meal (F) and soy bean (S) and gradually from 100 percent fish meal diet with 100 percent soy bean was replaced. Experimental diets included F70/S30, F30/S70, F50/S50, F0/S100 and F100/S0. The results showed that diets F70/S30 F100/S0 and better results in weight gain, specific growth rate, the coefficient of utilization of protein, feed conversion and daily food consumption was been. There are no significant differences between diets F70/S30 F100/S0. In terms of economic justification for making commercial diets fed F70/S30 recommended.