Background and Objectives: In order to implement fishing management, information about the distribution of the desired species, its optimal habitat and its relationship with environmental and ecological variables is necessary. Narrow-barred Spanish mackerel is one of the best fisheries in the Persian Gulf. This study considered the possible relationship of spatial, temporal and some satellite derived environmental variables on Scomberomorus commerson Catch Per Unit Effort (CPUE).
Methods: This study was conducted in the Northwest of Persian Gulf (coasts of Khuzestan province) from 2013 to 2018 to investigate the relationship between Catch Per Unit Effort (CPUE) of Narrow-barred Spanish mackerel and environmental variables such as Sea Surface Temperature (SST), Primary Production (PP), light extinction coefficient (Kd) and chlorophyll-a. These variables were derived from the MODIS sensor in proportion to the fishing time from 2013 to 2018 from NASA website. The amount of CPUE was calculated and recorded in the same years. Then, the relationship between them was assessed using statistical tests.
Findings: The results of this study showed that during the study period, the fish caught had an average total length of 75 ±4 cm and the average weight of fish caught was 950 ± 5 grams. The results of the mean of variables during the study period showed that the average total catch during the study period was 1680.3kg, the average temperature was 25.25 ° C, the average chlorophyll-a was 1.17 mg/m3, the average primary production was 1.85 g/m2/d, the average extinction coefficient was 0.14 m and the average catch per unit of effort was 4.62 kg/h. Also, the results of statistical tests showed that the amount of catch per unit effort with the month of sampling (p<0.01) and longitude (p<0.01) had a significant negative relationship and There is a statistically significant positive relationship with total catch (p<0.01) and sampling year (p<0.01) and temperature (p<0.01). Also, the results of principal component analysis showed that chlorophyll-a, surface temperature, sampling month, primary production and extinction coefficient were high correlation with the first component, catch per unit effort, total catch and latitude were high correlation with the second component.Longitude showed high correlation with the third component and latitude and surface temperature showed high correlation with the fourth component.
Conclusion: In general, according to the results of this study, longitude, month and year of sampling and surface temperature have the greatest impact on the amount of catch per unit effort of this fish. This research can be effective in the implementation of ecosystem management of this species. Since the early step in ecosystem management is the sufficient knowledge on ecosystem and distribution of target species in relationship to environmental variables, therefore this research could help to implementing of ecosystem based management in this region.
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