جستجوی مقالات مرتبط با کلیدواژه "catch per unit effort" در نشریات گروه "شیلات"

In the fishing season of 2018, fishing information, atmospheric and marine information were collected for investigating the effect of environmental factors on the amount of catch per unit effort (CPUE) of banana shrimp (Penaeus merguiensis) and Sartiz (Metapanaeus affinis) in Bandar Abbas, Qeshm and Bandar Kolahi by Means of ranking tests, permutation test and regression calculations.According to the result obtained during 49 trawl operations, the total weight of shrimp was 1932 kg, including 1379 kg of Banana shrimp with an average of 12.56 (with a 95% confidence interval of 9.68 to 15.45) kg/hour and Jinga shrimp with an average of 5.18 (with about 95% confidence was recorded (3.69 to 6.68) kg/h. The RDA ranking chart showed that the CPUE of Banana shrimp had a direct and significant relationship with the factors including depth, rainfall, and sea surface temperature. In addition, it had a slight relationship with wind speed, cloudiness, humidity, salinity, and wave height. Instead, Jinga shrimp CPUE was directly related to salinity and sea surface temperature and was inversely related to wave height and humidity. Based on the permutation test results, these relationships were not significant. The effect of environmental factors on Banana shrimp CPUE by regression calculations showed that the variables of floating speed and salinity (P<0.01) and humidity and cloudiness (P<0.05) were significant in the negative binomial regression model. The pseudo-Poisson model indicated the variables of sea surface temperature (P<0.05) and salinity (P<0.1) had a significant effect on the CPUE of Jinga shrimp. The present study shows the extent and manner of influence (direct or inverse) of environmental factors on the amount of successful shrimp fishing.

The kutum (Rutilus kutum) is one of the most important and commercial species of the bony fishes and comprises up to 70% of catch composition in Iranian waters of the Caspian Sea. Catch and effort data of the beach seine fishing cooperatives as well as the distribution and important species index (ISI) in the fishing areas were assessed between 1996 and 2011. The kutum had a wide distribution in the Iranian waters of the Caspian Sea during the study period. The minimum proportion in catch, distribution and ISI for kutum were observed in the east coast of the Golestan province, while the maximum values were observed in the Guilan province (before 2006) and Babolsar fishing area (from 2007 to 2011). The ISI was higher between 2006 and 2011 than the previous years, and the maximum level of this index was obtained 78 in 2008. The CPUE increased from 1996 to 2011. The maximum CPUE between 1996 and 1999 was in the range of 220.3 to 384.5 kg/haul (observed in Astara fishing area), while between 2008 and 2011 the maximum CPUE was in the range of 364.3 to 566.3 kg/haul (observed in Babolsar fishing area). In general, distribution and ISI of kutum between 1996 and 2011 were higher in the Mazandaran province than the other fishing areas.

This study carried out in the Iranian waters of the Caspian Sea during 2009-2010، and aimed to determine species composition، relative abundance، and absolute abundance estimated of biomass. Research vessels using 9 m bottom trawl for depths less than 10 m and 24. 7 m bottom trawl for depths above 10 m. Trawling was conducted in 90 stations that were selected using a stratified random design. In each station، trawling carried out up to 30 minute and 2. 5-3 knot. In 2009 and 2010، 84 and 28 sturgeon fish were caught، respectively. Persian sturgeon was more than 83 to 100 percent of the catch. The mean total length of Persian sturgeon was 61. 9±28. 7 cm (spring) and 40. 5±27. 9 cm (autumn) in 2009. This value was 54. 7±23. 5 cm and 60. 2±17. 7 cm for spring and summer in 2010، respectively. Absolute abundance of sturgeon was estimated 1. 31 million fish in the Iranian waters of the Caspian Sea during spring but it increased to 3. 46 million fish in autumn 2009. Absolute abundance in 2010 was 831100 and 779200 fishes in spring and summer 2010، respectively. Biomass of sturgeon fish was 2019. 7 and 3014. 3 tons in spring and autumn 2009، respectively. These values were estimated 760. 6 tons (spring) and 855. 0 tons (summer) for the year 2010. The results show that Iranian fisheries organization policy in production and releasing of fingerlings has been unable to prevent the loss sturgeon stocks. Therefore، it seems the only way to recover their stocks is rebuild natural spawning areas، nursery grounds and preservation of them up to they reach commercial size.