علوم زیستی دریا
Abdolsamad Dehghan; Ahmad Savari; Tooraj Valinassab; babak Doustshenas; Parvin Sadeghi
Abstract
To study the effects of monsoon on the richness and seasonal changes in the density of crabs in the intertidal area of the southern coast of Sistan and Balouchestan province, sampling was carried out in 2013 (based on the intensity of the monsoon) in three seasons: pre-monsoon, monsoon and post-monsoon ...
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To study the effects of monsoon on the richness and seasonal changes in the density of crabs in the intertidal area of the southern coast of Sistan and Balouchestan province, sampling was carried out in 2013 (based on the intensity of the monsoon) in three seasons: pre-monsoon, monsoon and post-monsoon using quadrats (Dimensions 50x50 cm and depth 10 cm), in 5 different stations. During the research, organic matter, salinity and temperature were also measured. Altogether, in this study, 17 species belonging to 10 families and 15 genera were identified. Based on the two-way ANOVA analysis results, a significant difference in brachyuran crab density and diversity was observed between the three seasons. The lowest species richness and density between the three seasons were recorded during the monsoon due to environmental stress. On the other hand, due to the presence of favorable environmental conditions for crabs, the highest density and species richness were observed in the prior and post-monsoon seasons. The statistical comparison of density in different stations showed that due to the significant relationship between density, grain size, and other environmental conditions, Jazireh Krahang and Gowater stations have the highest amount of TOM throughout the year, the presence of mud substrate and mangrove ecosystem has the highest species richness and density. In contrast, the lowest density has been recorded at Tiss and Bris. Monsoons can affect the ecology of living organisms differently. Totally, Monsoons can cause a decrease in the density and abundance of crabs during monsoon season in the intertidal zone due to their extensive effects on environmental conditions such as the content of organic matter and substrate conditions.
eelia eatemadi; ahmad savari; Tooraj Valinassab; Nasrin Sakhaei
Volume 11, Issue 1 , November 2012, , Pages 16-30
Abstract
This study was carried out in three inter tidal zones in the Iranian coast of Gulf of Oman, in 2010 to identify the species belonging to Family Ocypodidae and to investigate effect of monsoon on ecology of crabs. Two species of genus Uca (U. sindensis and U. iranica) from Jask and Khour-Khalasi study ...
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This study was carried out in three inter tidal zones in the Iranian coast of Gulf of Oman, in 2010 to identify the species belonging to Family Ocypodidae and to investigate effect of monsoon on ecology of crabs. Two species of genus Uca (U. sindensis and U. iranica) from Jask and Khour-Khalasi study area and one species of genus Ocypode (O. rotundata) from Vanak beach were identified. The results were used to verify previous reports on species identification. Monsoon was found to affect distribution and frequency of these crabs. The maximum and minimum relative density were observed in pre-monsoon (May, 9.33 individual/m2) and monsoon (September, 6.38 individual/m2), respectively. Dense distribution of Uca was found in the muddy beaches of Khour-Khalasi and the genus Ocipode in the sandy beaches of Vanak area.
Marzieh Afshari; Tooraj Valinassab; Seyed Seyfabadi
Volume 10, Issue 1 , September 2012, , Pages 12-22
Abstract
In order to study the feeding biology of the Japanese Threadfin Bream in the Northern parts of Oman Sea (Chabahar Area), a total of 212 specimens were collected in 2009-2010, and different indices of VI, FP and GSI were taken into consideration. Of total stomachs, 51, 44 and 117 numbers were full, semi-full ...
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In order to study the feeding biology of the Japanese Threadfin Bream in the Northern parts of Oman Sea (Chabahar Area), a total of 212 specimens were collected in 2009-2010, and different indices of VI, FP and GSI were taken into consideration. Of total stomachs, 51, 44 and 117 numbers were full, semi-full and empty, respectively. The VI index was estimated 55.2% , and amount of Food Preference Index were estimated as: Crustacean (63.2%), Fishes (38.9%), Molluscs (36.8%), Nematoda (25.3%), Polychaeta (8.4%), Sipuncula (7.4%), Foraminifera (6.3%), Phytoplanktons (4.2%), Seeweeds (2.1%) and Nemertean worms (1.1%). The maximum and minimum Gastro-Somatic Index for males were in autumn and winter season; and for females in summer and spring. It was concluded that N.japonicus is a moderate feeding fish and it’s main food is Crustacean and minor foods are Molluscs and Fishes.