The Relationship Between The Distribution Of Illex Argentinus Resources And Environmental Factors And The Prediction Of Fishing Grounds

The sea area of Argentina’s exclusive economic zone is located in the southwest Atlantic region(FAO NO.41 fishing area),and its sediment is muddy and muddy.There are two opposite water masses,the Brazilian warm current and the Malvinas cold current,and the La Plata River transports a large amount of nutrients to the sea area,providing a sea area for different fish species to breed and feed,making it one of the world-famous marine fishing grounds.Its fishery resources are particularly abundant in the continental shelf area of 35°-52°S.the main economic fish species include cod,Illex argentinus,Argentine red shrimp and so on.Based on the fishing log data of squid fishing vessels of Chiarpesca,an overseas company of Shanghai Jinyou Ocean Fisheries Co.,Ltd.,and combined with marine environmental data,this paper analyzes the influence of marine environmental factors on the distribution of Illex argentinus resources.The main factors affecting the distribution of Illex argentinus resources were screened by GAM model,and the maximum entropy model was constructed to study the change of habitat center of gravity and the influence weight and interval of marine environmental factors.The neural network was used to analyze the changes of Illex argentinus fishing grounds.1.The influence of marine environmental factors on the distribution of Illex argentinus resources based on linear regression.Through the linear statistical analysis of the effects of environmental factors on the CPUE of Illex argentinus,it is found that the most suitable ranges of sea surface temperature,sea surface height,sea surface salinity and chlorophyll concentration are 7-9℃and 13-16℃,0.1-0.2 m,33-35 and 0-2 mg/m~3,respectively.2.Screening of marine environmental factors based on GAM model.The results of GAM model showed that longitude,latitude,sea surface temperature,sea surface salinity,chlorophyll concentration and sea surface height were significantly correlated with CPUE,while sea surface wind speed had no significant effect on CPUE.The sea surface temperature in the squid fishing fleet production area is mainly distributed in 9-16℃,the sea surface height is mainly distributed in 0-0.2m,the sea surface salinity is mainly distributed in 33-35,and the chlorophyll concentration is mainly distributed in 0.6-1.6mg/m~3.The distribution of fishing grounds is southwest-northeast,which is consistent with that of the Argentine continental shelf.3.Study on marine environmental factors based on maximum entropy model and habitat prediction of Illex argentinus.Through the maximum entropy model,the monthly optimal interval and influence weight of marine environmental factors affecting the distribution of Illex argentinus fishing grounds are obtained,and the accuracy of the maximum entropy model is verified.The results show that the AUC value of the model accuracy index is more than 0.90 and the standard deviation is less than 0.1.the simulation effect of the model is good.The contribution rate of sea surface temperature has always been high,and the optimum temperature distribution is between 11℃and 16℃.The temperature gradient from the inshore to the outer sea changes violently,and the Malvinas cold current path is basically consistent with the continental shelf trend.The sea surface height has the highest contribution rate in May,and the most suitable height is distributed in 0.05-0.2m.The sea surface height more reflects the change of heat in the ocean,which leads to the change of fishing grounds.The optimum range of sea surface salinity is 33-34,which is more sensitive to salinity in spring and summer,and the contribution rate of chlorophyll concentration is higher from May to June,and the optimum concentration is basically distributed in 0.2-1.6mg/m~3.It is considered that due to the continuous growth and development of Buenos Aires-Patagonia group,the demand for bait is increasing.4.Predict the change of Illex argentinus fishing ground based on neural network model.Through the construction of different models,the optimal model was selected according to MSE and ARV,the CPUE value of Illex argentinus was predicted by the optimal model,and the change of Illex argentinus fishing ground was analyzed.The results show that the optimal model is 6-9-1 model,and the environmental factors such as SST,SSH,SSS,LON,LAT and CHL have influence on the fishing ground distribution of Illex argentinus.The CPUE value predicted in 2019～2022 is increasing year by year.Combined with the change of annual production,it can be predicted that the production of Illex argentinus will show an upward trend in the next few years.The results of the model also show that the Illex argentinus summer spawning stock from December to February of the following year.South Patagonic stock and Bonaerensis-North Patagonic Stock gather in 40°S-46°S and 58°W-62°W to form a new summer spawning group from January to March each year.Part of the Illex argentinus population stayed in the area in February;some of the Illex argentinus adults gathered southward in the Malvinas Islands and spawned in the Malvinas Islands from April to August each year,becoming a new South Patagonia group;some larvae and juveniles continued to grow on the continental slope near 38°S and began to spawn from July to September each year,becoming a new Buenos Aires-Patagonia group.The younger population continued to move northward to reach the slope between 24-34°S(Brazilian waters),and then spawned from July to November after maturity,becoming spring spawning stock.