جستجوی مقالات مرتبط با کلیدواژه "صید" در نشریات گروه "محیط زیست"

The purpose of this study was an estimation of the exploitation and also determination of some biological aspects for trapped Pharaoh Cuttlefish by wire pot (Gargoor) in Bushehr province (north of Persian Gulf). The data collection process was carried out from February 22 to April 19, 2017. The landing and yield of caught Pharaoh Cuttlefish by wire pots in Bushehr province, for 12 years, were 354.833 tones and 162.260 kg. km-2. year-1, respectively. The length (mantle length) and weight range of caught Pharaoh Cuttlefish (300 biometeried specimens) were 13-36 (24.62 ± 4.59) cm and 300-4200 (1870 ± 791.61) gr, respectively. Randomization Test and Two Independent Samples Kolmogorov-Smirnov Test were used for comparing the length frequencies, while showed a significant difference in all different parameters of catch; such as soak depth of Gargoors, soak time of Gargoors and types of vessel (p=0.001). The average of condition factor for Pharaoh Cuttlefishes was 1.25 which indicates the favorable living conditions of trapped Pharaoh Cuttlefish by Gargoor. Independent Samples T Test was used for comparing the condition factors, while just showed a significant difference in soak time of Gargoors (p=0.001). The results showed that due to the overlapping and synchronization of the fishing and reproduction season of Pharaoh Cuttlefish in Bushehr province and based on the range of length and weight frequencies of trapped Pharaoh Cuttlefish by wire pots, it can be stated that fishing operation using wire pots is a selective method for Cuttlefish.

Sturgeons are considered to be the most valuable fish in the world and the Caspian Sea. the Collapse of the former Soviet Union and the uncertain division of the Caspian Sea unfortunately have led to environmental problems, as well as an increase in illegal fishing, has led to a significant reduction in the valuable species of the Caspian Sea. In spite of various management inconsistencies, advising and managing the Islamic Republic of Iran after the glorious victory of the Islamic Revolution led to the adoption of uniform policies of the Caspian Sea administration, which can be used to control sturgeon fishing and increase the rebuilding of their reserves. After the glorious victory of the Islamic Revolution, significant activities have been undertaken in this area, including: the restoration of reserves and the release of infants to the sea, the cultivation of sturgeon in unconventional domestic waters and cages, increasing research centers and universities with the management of sturgeon stocks management and Introducing the precious Persian dish. Altogether, in spite of various management inconsistencies, the advisory and management of the Islamic Republic of Iran led to the adoption of uniform policies of the Caspian Sea administration, which could be used to control sturgeon fishing and increase the rebuilding of reserves. Between countries of the Caspian Sea, only Iran has been trying to solve this crisis, which is a significant reduction of sturgeon fish. Many activities, including the construction of reproduction and restore of sturgeons from Iran, have been carried out in this area, which could lead to worthy result.

Sampling of banana shrimp stock was occurred for estimating the biomass and distribution purposed by wooden trawler in aquatic habitat from January 2013 to January 2014. Towing operation was done from Sirik (26O 25’ E, 57O 01’ N) to Dargehan in north of Qeshm island (27O 02’ E, 56O 12’ N). Carapace length – total weight relationship for mixed gender was estimated as W= 0.0015L2.7868. Recruitment was occurred all around the year, but maximum was in July to November (63%). Exponential probability of capture was estimated as Pi=1/[1+exp(-0.56(Li-23.78))]. Biomass of banana shrimp was estimated as 1044.1 tone by swept area method and total allowable catch was estimated 835 tone. Maximum biomass of banana shrimp was 507.6 tone (about 48.6%) in depth layer of 5-10 m and the most concentration of the shrimp was belonging to west part of Hormoz Island. Optimum time to starting the catch season, based on the 28 mm (Cl) as optimum length of harvest, was estimated 1st October, 2013. Changes in natural mortality values could be effected the length of catch and optimum time of harvest too. The catchability coefficient, q, was estimated 0.000371 and total biomass was calculated 1232 tone by depletion method. Such difference in estimated biomass from two methods maybe belong to add juvenile to main stock during the catch season or increasing the body mass of each individual in the stock.