علوم زیستی دریا
Khatereh Mehrabani; Mohammad Khosravizadeh; Vahid Yavari; Seyed Mehdi Hosseini; Omid Beyraghdar Kashkooli
Abstract
The aim of this study was to estimate the amount and species composition of discards in bottom trawl fisheries in the Bosif fishing ground in the coastal waters of Khuzestan. Furthermore, the biological parameters of discarded species were assessed. Specimens were collected from commercial catch data ...
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The aim of this study was to estimate the amount and species composition of discards in bottom trawl fisheries in the Bosif fishing ground in the coastal waters of Khuzestan. Furthermore, the biological parameters of discarded species were assessed. Specimens were collected from commercial catch data of trawl vessels in three seasons, autumn and winter 2017 and summer 2018. The results showed that discarded samples included 33 species from 28 families. Orangefin Pony fish and striped piggy species were the most frequent species in this study. The results also showed that the mean length of most of the discards species was below 30 centimeters. The amount of discards per unit of catching effort was 57.33±9.87, 27.50±16.64 and 32.33±7.50 in the autumn, winter and summer seasons, respectively. The catch per surface area in autumn, winter and summer were 2.77 ± 0.064, 0. 73 ±0.39 and 1.73 ± 0.44 kg/nm2, respectively. The results showed that CPUE and CPUA in winter were significantly higher than those in autumn and summer (p<0.05). In general, the results of this study represent high fishing pressure on ecologically important species in Bosif fishing ground especially in their critical life cycle which may affect local ecosystem structure and function in future.
مهندسی دریا
Mohammad Taghi Mansouri Kia; Hamid Reza Sheybani; Elham Rajabi
Abstract
The only navigable river is the Karun River in Iran. Karun shipping history dates back to Nasser al-Din Qajar Shah. Climate change and drought, harvests more water and reduce its capacity, the existence of new railways and highways as the main competitors of cargo from the port of Mahshahr and Khorramshahr ...
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The only navigable river is the Karun River in Iran. Karun shipping history dates back to Nasser al-Din Qajar Shah. Climate change and drought, harvests more water and reduce its capacity, the existence of new railways and highways as the main competitors of cargo from the port of Mahshahr and Khorramshahr to Ahvaz due to the boom in river water transport has been falling.There are few studies on water transport in Karun river. In this study, some of their results are discussed in general. Then, based on the acceptance of the latest research, the most important physical barriers to river transportation have been identified and their remediation strategies adapted to the current situation. Then shipping Signs required of navigation and auxiliary's equipment for sailing have also been offered.Previous studies included :(Iranian structural consulting engineers, 2004; Adabdanan Consulting Engineers, 2004) and Especially (Scott Wilson and Piesold, 2005) It has been attributed to the heavy losses of water transportation, especially in the high tonnage of annual freight. The most recent study, ongoing surveys at the Khuzestan Water and Power Organization (Mansouri Kia, 2018) show that the transport medium (in the pessimistic scenario optimistic scenario about 700 thousand tons and 2133 thousand tons in the target year 1425), together with previous studies is the development of tourism can be no economic losses. Water transport is the base year 2020. Heavy financial losses were previously assumed for river transportation. The most important results of recent research suggest that these losses are reduced by modifying the design vessel dimensions.Another important result of the present study is identifying the physical problems for the Iranian rivers transportation and to provide solutions (except for the sediment removal problem that is being investigated at another study). Applying the research results on solving physical barriers and financial support by private investment (or other financing options), revive water transportation in Karun it is possible.
علوم زیستی دریا
Emad Koochaknejad; Ahamd Savari; Alireza Safahieh; Gholamreza Eskandari
Abstract
In this study age, growth and maturity of Hilsa shad in Khuzestan province were analyzed. 394 number of fishes from marine habitat (Life-Boseif), estuaries (Bahmanshir and Arvand) and rivers (Bahmanshir and Karoon) from February 2014 to September 2014 were collected using commercial fishing with gill ...
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In this study age, growth and maturity of Hilsa shad in Khuzestan province were analyzed. 394 number of fishes from marine habitat (Life-Boseif), estuaries (Bahmanshir and Arvand) and rivers (Bahmanshir and Karoon) from February 2014 to September 2014 were collected using commercial fishing with gill net. Total length and wet weight of each fish were measured with precision of 1 cm and 1 gram. Sagittal otoliths were extracted for age determination of the fish. Then abdominal cavity of each sample were opened for determining sex and maturity stage. Growth parameters were calculated using von Bertalanffy growth function (L∞=58.365, K=0.26, t0=-0.16). Phi-prime constant was obtained 2.95. Length and age at first maturity were obtained 27.32cm and 2.4 g respectively using logistic model to fit a and b parameters with observed data in spawning season.