JOURNAL OF MARINE BIOLOGY
Year:2014 | Volume:6 | Issue:23|Papers Count:10

Cadmium is one of the most important environmental pollutants that have been increased in parallel to population growth and industrial development in aquatic ecosystems such as the Caspian Sea in recent years. Marine invertebrates such as crustaceans and bivalves for the reason of sessile can absorb essential and non-essential heavy metals surroundings themselves and cause transfer them to top of the network food. This study was conducted to study filtration rate of Mytilaster lineatus and Palaemonelegans exposed to Cd (62 and 620 mgl-1) and its ability to remove these metals from water. The experiments were carried out in a designed mesocosm system. The results showed no significant different in filtration rate of M. lineatus and P. elegans exposed to Cd. These two species reduced the filtration rate and even they returned excess metals to the environment. It was also shown that the shrimp Palaemon elegans and bivalves Mytilaster lineatus can be the biological indicators for the assessment of cadmium in the aquatic environment.

The growth parameters, mortality rates and exploitation rate of Jinga shrimp (Metapenaeus affinis) in western coast of Khoozestan Province were assessed from August to December 2013 using length frequency analysis. The sampling was carried out once a month by using bottom trawl. The growth parameters for males and females were estimated employing modal progression and computer based FiSAT II software package using ELEFAN I program. The maximum mean length was calculated as 107.9±11.2 mm for female and 103.7±12.8 mm for male. The results showed that mean total length from August to October downswing. The asymptotic total length (L¥) was estimated to be 156.7 mm for females and 135.41 mm for males. The growth parameter K was calculated 2.1 Y-1 for females and 1.8 Y-1 for males. Theoretical age at zero length (t0) was calculated -0.088 yr for female and -0.1075 yr for male. The total mortality (Z), natural mortality (M) and fishing mortality rates (F) were estimated as 7.01, 1.74 and 5.27 for females and 5.25, 1.64 and 3.62 for males, respectively. The exploitation rate was 0.75 for females and 0.69 for males. Results indicated overfishing of Jinga Shrimp stock and a decrease in exploitation ratio is suggested.

In order to study the biological parameters and reproduction characteristic of Leptodius exaratus in intertidal zone of Hormoz Island, a series of research sampling carried out during 12 months in 2013. The sex ratio was estimated as male: female=47%:53%. Reproduction of the dominant species showed higher abundance of males than females. Sexual maturity in male occurred at 16 mm carapace length and in female at 13mm carapace length. Gonopod length in male crab is strongly correlated with the maturity and so is the number of eggs and gonad weight with the width of the abdomen in females.

The present study aimed to study the histological structure of body wall of sea cucumbers collected from the coasts of Persian Gulf in Hormozgan. In this regard, sampling was done from three regions in Hormozgan including Bandar Lengeh, Qeshm and Hormoz during 2010. 7 species including Holothuriaparva, Holothuriaaraenicola, Holothuriaatra, Holothuriahilla, Holothurialeucospilota, Thyonedura, Protankyrapseudodigita were indentified from the sampling sites. The histological structure of body wall was studied in all of collected species to evaluate the possible different among them. Firstly, all samples were anesthetized using magnesium chloride to prevent from visceral rejection and then fixed in 10% formalin. The samples were taken from body wall and then were processed through routine paraffin embedding technique, cut at 6 µm and stained with Hematoxylin and Eosin to study using light microscope. The results showed that the body wall consists of an epidermis, a dermal connective tissue layer, a layer of circular musculature and a mesothelium. Five pairs of longitudinal muscles are also observed in Holothuroids.

In this study, the comparative evaluation of some blood biochemical parameters of rainbow trout carried out in different sizes. The study was conducted in four weight categories include 5-10, 50-100, 300-500 and 600-800 g with total of 10 fish from each group. Then, blood samples were obtained through tail vein puncture and the non-heparinized blood samples were centrifuged for 5 minutes at 5000 g, and separated serum were used to determine with an automatic analyser machine (Persige 24 I) the levels of the factors. The results of blood biochemical factors in Oncorhynchus mykiss showed there were significant differences between the different size at levels of glucose, cholesterol, triglycerides, calcium, phosphorus, chloride, iron, total protein and albumin (P<0.05). Also, results showed there were no significant differences at values of sodium and potassium (P>0.05). The results showed that with increasing age and size of fish the levels of cholesterol, triglycerides, phosphorus, iron, total protein and albumin were increased and the levels of glucose and chloride were decreased. But, no change observed in value of sodium and potassium blood serum. The results of this study indicated that there were significant difference in the blood biochemical parametersina species of fish in at different sizes.

Vibrio alginolyticus is a pathogenic and halophilic Gram negative bacterium belongs to family Vibrionaceae. The bacterium naturally found in temperate marine and estuarine environments, which cause different type of human infections like wound infection and otitis. Hence, the present study was conducted to isolate symbiotic Vibrio alginolyticus from Persian Gulf sponges and then characterize the isolates using API 20NE diagnostic kit. For this purpose, 4 different sponge species (Algelas sp. and Spongia sp.) were collected from 1 to 5 meters depth of Bandar Abbas Shahid Haghani warf’s surrounding waters (August 2013) by scuba diving. The sponges with sea water have been transferred to the microbiological lab and after washing under distilled water, extracted using sea water. Then the extracts were serially diluted and subsequently cultured on Marine Agar2216 and TCBS media. The plates were kept at 25oC for 48 hrs and the isolates were preliminary characterized using: Gram staining, Oxidase, Catalase and Citrate tests. Finally, the isolates were biochemically identified through API 20NE kit (Biomerieux, France). The results obtained from this study indicated that totally 22 bacterial isolates were gram negative. Out of all, 4 isolates were identified as Vibrio alginolyticus. Because the bacterium is pathogenic for human therefore, the results proposed that the people who live in this geographical area should be aware for the health risks of this bacterium and in case of any wound or abrasion don’t swim in this part.

The diet of Scomberoides commersonnianus, a commercially important fish of Carangidae, has not been investigated in Iran. In this study, 563 fish of Scomberoides commersonnianu type were caught in Khuzestan waters during fifteen months of sampling from Aban, 1390 to Dey, 1391. In the present study, the gastro-somatic index and food composition of this fish were examined during the fifteen months in Khuzestan waters. The effects of season, length, sex and maturity of the fish on the gastro-somatic index were assessed. This index was also adopted in the determination of feeding intensity. The results showed that feeding intensity was similar in both sexes. There was a significant difference among the seasons (p<0.05), except for the one between spring and summer (p>0.05). Furthermore, feeding intensity in cool seasons (fall and winter) exceeded that of warm seasons (spring and summer). Also, the lowest level of feeding intensity was observed in spring (2.074), but it reached the maximum rate during winter (3.379). It was also found that feeding intensity rate among small fish was more than large ones and the gastro-somatic index increased with the decrease in length. The results indicated that this fish had a selective behavior in choosing its food items and fish and shrimp constituted the primary and secondary types of food, respectively. The fish which belong to Clupeidae, Carangidae, Mullidae, Leiognathidae, Pristigasteridae, Teraponidae families were found in S. commersonnianus.

Estuaries are the main crossing areas between rivers and sea ecosystems. The Shirud River is located in the west of Mazandaran province. Sampling of sediments was done monthly for one year (Jul 2012- Jun 2013). Five stations were sampled, includes two stations in upper part, one station in delta of estuary and two stations in the sea. Environmental parameters such as salinity (ppt), pH, water temperature (Co) and depth (cm) were recorded in any station. 5182 number macrobenthos were counted; there were recognized 36 genera, 25 families and 15 orders. The most abundant recorded for Obesogammarus sp. as 36%. In accordance with the results, salinity and depth of water affect the density of Macrobenthos (p<0.05), however pH did not effect on density and diversity, though (P>0.05). Also temperature changes cause modifications in density and diversity among different species of Macrobentozes during different months, so that the most and least density were recorded during July and January, respectively. The most and least diversity were shown during September and March (p<0.05). In average the most live mass was realized in August (1.61 gr/m2) and the least live mass was for March (0.03 gr/m2). The average ecological indices results are as follows: Shannon-Wiener 0.83; Simpsons Dominance 0.48 and Margalef Richness 2.42, there were a significant difference between indices during different months in a year (P<0.05).