جستجوی مقالات مرتبط با کلیدواژه « recruitment » در نشریات گروه « زیست شناسی »

This study was conducted to determine the virtual population analysis, recruitment pattern and cohort analysis of blue swimming crab (Portunus segnis) in coastal waters of the Persian Gulf and the Oman Sea (Hormozgan province). Sampling was carried out monthly by bottom trawl from May 2010 to October 2011. Results of Thompson and Bell prediction analysis showed that the maximum sustainable yield (MSY) was 302.2 tons, total survival biomass was 131.6 and maximum economic yield (MEY) was $625.3. A 10 % decrease in the level of fishing effort is recommended to ensure sustainability of the blue swimming crab stock.Maximum of recruitment pattern was in October (age of recruit 0.5 Y-1) with average carapace width of 91 and 110 mm for female and male respectively. Three cohorts were distinguished based on Bhattacharya's method for both sex of blue swimming crab.

The purpose of this study was to investigate the reproductive and recruitment patterns of Uca sindensis crab in intertidal zone of Pohl port in Bandar Abbas. The coordinates of sampling area were in latitudes 26 degrees and 45 minutes to 27 degrees and 10 minutes north and longitude 55 degrees and 20 minutes to 56 degrees east with area of 26.4 km2. Samples were monthly taken from October 2009 to September 2010 in the intertidal zone of Pohl port when the tide was ebb. 10 quadrates with area of 5.0X5.0 m2 were used for sampling, as every quadrates excavated to a depth of 30 cm. samples collected were transported to the laboratory. Samples were biometried using caliper with precision of 0.05 mm and eggs counted using the method of Litulo, 2004. Analysis and recruitment curves and frequency distribution of crab population was done by FISAT II software. The results showed that the reproductive pattern in this species was seasonal, and starting from April to August. Ovigerous females in length class of 4.5 to 11.5 mm were more abundant than any other classes with average of Carapace width about 7.56+-2.24. There was linear and direct relationship between carapace width and eggs, and positively relationship between them. Carapace width of Female crabs which carry about 2340 eggs was 4.5 however female crabs with 11,300 eggs was 11.5 mm. Carapace width showed a linear relationship with abdominal width. A peak was observed quite regularly in recruitment that was started in October and most of its value was between June and July months. Finally, this study showed that in the subtropical region of Pohl port, the amount of organic matter and soil temperature were two key factors that have the most effects on reproduction, growth and population of fiddler crabs.