Age and growth of a population of Varicorhinus trutta (Heckel) from Tigris river at Salahuldin province have been investigated during the period from September 1999 to August 2000. A total of 156 fishes were collected from two stations at Tigris river using small meshed gill nets. The age data revealed that the species under investigation reached to a maximum age of seven years and approximately 46 cm long. The population of this species in Tigris river at the sites of study was dominated by 3 and 4 years classes. There were no marked differences in growth or longevity between the sexes. Determination of length-weight relationship revealed that the growth of both sexes in the species under investigation was allometric and the values of both sexes showed that there were clear relationships between the maturity stage and condition factor values as the highest values appeared during the breeding season months (March till July).
Abstract
The analysis of Least Squares: LS is often unsuccessful in the case of outliers in the studied phenomena. OLS will lose their properties and then lose the property of Beast Linear Unbiased Estimator (BLUE), because of the Outliers have a bad effect on the phenomenon. To address this problem, new statistical methods have been developed so that they are not easily affected by outliers. These methods are characterized by robustness or (resistance). The Least Trimmed Squares: LTS method was therefore a good alternative to achieving more feasible results and optimization. However, it is possible to assume weights that take into consideration the location of the outliers in the data and det
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Segmented regression consists of several sections separated by different points of membership, showing the heterogeneity arising from the process of separating the segments within the research sample. This research is concerned with estimating the location of the change point between segments and estimating model parameters, and proposing a robust estimation method and compare it with some other methods that used in the segmented regression. One of the traditional methods (Muggeo method) has been used to find the maximum likelihood estimator in an iterative approach for the model and the change point as well. Moreover, a robust estimation method (IRW method) has used which depends on the use of the robust M-estimator technique in
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The female Shabout were collected as samples from Dijla river in Baghdad. The oocyte developmental stages were divided in to nine stages, based on nucleus structure , cellular inclusions and ovarian follicle structure ,they are:-( Oogonia stage , Early Perinucleolar Stage , Advanced Perinucleolar Stage , Cortical Alveoli Stage , Primary Yolk Stage , Secondary Yolk Stage , Tertiary Yolk Stage , Migratory Nucleus Stage , Hydration Stage(
) were taken from three stations at Al-Razzazah lake,by using a range of gill nets and seine nets. A total of 318 fish were taken from all stations. The age data determined from the scales showed that there were eight age classes present in station 1 and 2 and seven age classes in station 3. The increment in length of A. latus at the area of study showed a tendency to decrease with the increase in age after the fourth year of life. The length- weight relationships of both sexes specimens are expressed by the following equations: Log ï· = -1.93 + 2.67 Log ï¬â€¦.. for station (1) fish Log ï·= -2.08 + 2.74 Log ï¬ â€¦. For station (2) fish Log ï·= -2.02 + 2.39 Log ï¬ â€¦. For station (3) fish&n
... Show MoreDuring the study the current selection seven stations in the Zab River bottom and the Tigris River took samples a month to study the signs of bacterial contamination study coliform and colon fecal Almsobhaat and Almsobhaat Bazah and the total number of bacteria and bacterial gangrene gas causing Knkeran as well as a study to isolate and diagnose some races and types of bacterial pathogens in water or intensityusing the traditional system and the system of intestinal bacteria
(3)
The morphological description and histological structure of the
olfactory organ of Parasilurus triostegus (Heckel) have been
investigated. The olfactory organ situated on the dorsal surface of the
head infront of the eye.
It is represented by elongated olfactory sac, in which the
olfactory Lamellae arranged as Rosette- like pattern .
The olfactory sac connected with the olfactory bulb by short olfactory nerve. The olfactory bulb which situated near the olfactory sac connected wi
... Show MoreLandSat Satellite ETM+ image have been analyzed to detect the different depths of regions inside the Tigris river in order to detect the regions that need to remove sedimentation in Baghdad in Iraq Country. The scene consisted of six bands (without the thermal band), It was captured in March ٢٠٠١. The variance in depth is determined by applying the rationing technique on the bands ٣ and ٥. GIS ٩. ١ program is used to apply the rationing technique and determined the results.
Monthly water samples from three stations in Diwanya river at Diwanyia city were collected during December 1999 to June 2000. Variables from each stations were determined including ; temperature, pH ,dissolved oxygen, dissolved carbon dioxide , alkalinity ,total hardness, calcium ,magnesium , phosphate, nitrite, nitrate, chlorophyll-a , and total number of phytoplankton .The river considered as fresh water , alkaline ,very hard .The parameters recorded at different values from up and down stream.
A total of 722 algal taxa are recorded in Diyala River by different authors. Most of the identification algae belong to three Divisions: Bacillariophyceae (367, 50.8%), Chlorophyceae (179, 24.8%), and Cyanophyceae (126, 17.5%).