INTERNATIONAL JOURNAL OF MARINE SCIENCE AND ENGINEERING
Year:2012 | Volume:2 | Issue:3|Papers Count:5

Free surface modeling plays an important role in some ocean structures design, especially in Oscillating Water Column (OWC) devices. Boundary element method (BEM) is a suitable method for free surface modeling due to its simplicity, quick solving, and low data storage requirement.In this paper, BEM was used for free surface modeling in OWC chamber and out of it. Linear kinematic and dynamic boundary conditions were used for free surface out of OWC chamber and nonlinear forms were used for free surface in the chamber. These boundary conditions were descritized by finite differences method (FDM). Also, some thermodynamics relations were applied for trapped air behavior modeling in OWC chamber. Wave specifications in Chabahar region due to its high power waves entered in programming code as input data.The results show a good agreement with results of other researches. Also, it is concluded that Iranian sea waves have no good potential for use ordinary OWC devices, because, a little power (about 10 KW) can be extracted from an OWC, in the best point.

Malathion (S-(1, 2-dicarboethoxyethyl) O, O-dimethyl phosphorodithioate) is one of the organophosphate pesticides comprehensively used in agriculture fields throughout the world. In spite of widely used, little information are available about DNA damage in aquatic organisms. Therefore, the present study carried out to investigation of DNA damage induced by malathion in Cyprinus carpio (Pisces: Cyprinidae) using single cell gel electrophoresis. The condition of experiment was determined in static system. The specimens were exposed to different non-lethal concentrations (0.5, 1.5 and 3 mgL-1) of the malathion for 96 hour (short-time exposed). Our results showed, the specimens exposed to different concentrations of malathion exhibited significantly higher DNA damage in their blood cells than the control sample (P<0.05). This study confirmed that the comet assay is useful method in determining genotoxicity of pesticides. Fish can be used for biomonitoring of the genotoxic pollutants in aquatic environment. Furthermore, DNA strand breakage can be used as biomarker in ecotoxicological studies.

Accumulation of trace metals in sediment can cause severe ecological impacts. The present study determines the elemental concentrations and chemical partitioning of heavy metals in surface sediment of Shadegan wetland. Shadegan wetland is one of the most important wetlands in southwest of Iran and it is in Ramsar-listed wetlands. For this purpose, 7 sampling stations were selected for sediment collection in this wetland during autumn 2011. Physico-chemical parameters including pH, EC, total organic materials (TOM), grain size fraction and elements (Cr, Pb, V,) in sediments were measured. Subsequently, lithogenous and anthropogenic portions of trace metals in sediment, along with Igeo and IPOLL indices were measured. According to obtained results, Pb (25%), and Cr (14 %), had highest anthropogenic portion in study area. More ever, strong and positive meaningful relation between Cr and V shows that Cr has oil origin in the area of the study. Also, measured physico-chemical parameters have no role in controlling the trace elements concentration. The two pollution indices used in the present investigation (Igeo and IPOLL) are indicative of different pollution intensity in Shadegan aquatic environment.

The growth parameters, mortality rates and exploitation population dynamic parameters and exploitation rate of Psettodes erumei were assessed between July 2010 to June 2011 using length frequency analysis. The data were collected from landing sites of Jask, Bandar Abass, Kong and Qeshm Hormozgan province waters. Using total weight (W) and total length (TL) data, the length- weight relationship of this fish species was described as W=00037/L33652/ pertaining to alometric growth. Asymptotic length (L¥)=74.55 cm, coefficient growth (k)=0.23 year-1, t0=-0.61, longevity (tmax)=12.43 years and the growth performance index ( F’)=3.10 were estimated through the ELEFAN I routine and other modules from the FISAT program. Total mortality (Z), natural mortality (M), and fishing mortality (F) were then calculated as 1.2 year-1, 0.51 year-1, 0.69 year-1 respectively. Although, the estimated exploitation ratio (E=0.57) was well fitted with the optimum level, careful examination of exploitation rate (U) revealed that the major part of the stock (> 48% length frequency) is being fished out of the defined optimum length. Consequently, the need to improve fishing methods seems mandatory in the future to ensure that total landings do not exceed 525 tons predicted maximum constant yield (MCY).

In this study, we have investigated the effects of mix of Tomato (Solanum lycopersicum) & Carrot) Daucus carota (and red Bell pepper) Capsicum annuum (as a natural pigment source and astaxanthin as synthetic pigment sources on the skin colour of cichlid fish (Astronotus ocellatus sp., Agassiz, 1831), which are generally white with red patches in the dorsal skin. The fish were fed diets containing 100 mg kg-1 astaxanthin and natural pigment. The amount of both natural and synthetic pigment sources given as feed was 100 mg kg-1, and the experiment was continued for 60 days.Total carotenoid content of the fish was determined spectrophotometrically at the end of the experiment. As a result, while a visible change of colour in the skin of the fish fed on the feed containing astaxanthin was observed with 0.43±0.2 mg g-1 of pigment accumulation, a relatively change of colour was observed in the skin of other fish that were fed on the feed containing powder of Tomato & Carrot and red Bell pepper with 0.35±0.2 mg g-1 of pigment accumulations, respectively. Therefore, it was determined that these pigment sources have an effect on the colour of cichlid fish.