Remote Sensing Of Relationship Between The Environment And Spatiotemporal Distribution Of Light Falling-net Fishing Ground In The Western Guangdong Waters

Relationship between the spatio-temporal distribution of light falling-net fishing ground and Decapterus maruadsi with marine environment?including sea surface wind?SSW?,sea surface temperature?SST?,ChlorophyII a concentration?Chl a?and Sea level Anomalies?SLA??in winter?January to February?and summer?August to September?during2011-2015 in the western Guangdong waters was studied,using Generalized Linear Models?GLM?,Generalized additive models?GAM?,fishing ground gravity,correlation analysis and other methods.The main conclusions were as follows:?1?The environmental effects on seasonal changes in the spatiotemporal distribution of light falling-net fishing ground showed that the suitable SST and Chl a of fishing ground was 17-23°C and 0.2-0.6mg/m³ in winter,27-29°C and 0.2-2.0 mg/m³ in summer.?2?Standardize Catch Per Unit Effort of light falling-net was higher in summer and lower in winter.Fishing ground gravity migrated to the east about 1°from winter to summer.?3?Influenced by the Qiongdong-Yuexi upwelling and the coast flow caused by the monsoon,Chl a and SST were mainly negative correlation in the western Guangdong waters with high SSW,low SST,high Chl a in winter;low SSW,high SST and low Chl a in summer.However,in the coastal waters of 111-112°E and 19.5-20.75°N,Chl a and SST showed posi Combined with existing research.In winter,the regulation of SST on zooplankton reproduction,feeding and other life activities may affect the phytoplankton through the food chain and cause changes in Chl a.?4?According to GAM model and correlation analysis,the environmental effects of the seasonal variation of the resources and spatial-temporal distribution of Decapterus maruadsi were explored.Results showed that the catch per unit effort?CPUE?of D.maruadsi in the western Guangdong waters had a significant positive linear correlation with longitude,and the D.maruadsi populations were concentrated in the east of the study area.The total explaination of D.maruadsi CPUE in GAMs was47.40%,among which,the factors year,month,lunar phase,latitude,Chl a,SLA and water depth explained 9.30%,13.50%,6.50%,1.90%,1.70%,4.60%,and 9.90%,respectiovely.The D.maruadsi populations in the study were concentrated in the area of latitude 21°N,Chl a 0.1-0.5 mg·m^-3,SLA-0.05 m and water depth 80 m.The climate anomaly showed that the summer monsoon was delayed in 2014,which hindered the replenishment of the resources of the D.maruadsi and reduced the CPUE.The weakening of fishing intensity during the fishing off season and the increase of marine primary productivity brought by the upwelling flow provide a suitable environment for the D.maruadsi,the the D.maruadsi CPUE was higher than the winter in summer.The operation mode of light fishing net was affected by the moonlight intensity.At the full moon,the fish collection effect is weakened,therefore the D.maruadsi CPUE was reduced.