| The South China Sea is not only the largest land-margin sea in southern China,but also the only tropical sea.The sea area is about 3.56 million square kilometers,with a wide variety of resources and rich biodiversity.Among them,there are more than 25,000 fish resources and an annual catch of up to 7 million tons.However,in recent years,the phenomenon of overfishing in the coastal waters of the South China Sea has been serious,and fishery resources have gradually declined.In order to effectively curb this phenomenon,in response to the country's policy needs to implement a fishing quota system,the evaluation and management of marine fish resources has become the focus of research in the field of fishery resources.Sthenoteuthis Oualaniensis is a kind of oceanic cephalopod.It has abundant resources in the South China Sea.According to the Beidou information collection system,the resource of Squid in the South China Sea is estimated to reach 2,049,400 tons,with a catchable amount of 994,000 tons,which has huge development potential.In order to ensure the long-term sustainable development of the Squid resources in the South China Sea,scientific evaluation of the resources of Squid Squid in the South China Sea and the analysis of its catchable capacity are important.The research area in this paper is 8°N?12°N,108°E?116°E,and the time span For 2013-2019,the main research results are as follows:(1)This article uses the production data of Squid from South China Sea from 2013 to 2019.First,the generalized additive model is used to standardize the catch per unit effort(CPUE)of Squid.The relationship between CPUE and time and space factors(month,latitude and longitude),marine environmental factors(sea surface temperature,sea surface chlorophyll a concentration,sea surface wind speed and sea surface height)is analyzed and discussed.The sea surface chlorophyll a concentration is 0.09?0.13 mg·m-3,the sea surface temperature is 27?29?,the sea surface wind speed is 4.5?7.0 m·s-1,and the sea surface height is within the range of 0.6?0.75m.(2)This paper uses the Simpson formula and Fourier series in the numerical analysis to modify the background value of the ordinary gray model and correct the residuals,and establish an optimized gray GM(1,N)model to improve the prediction accuracy of the CPUE of the southern sea squid.Results.It shows that in the prediction of the CPUE of the squid,the optimized gray GM(1,N)model reduces the average relative error from 7.78%to 2.54%;in the prediction of the CPUE of the squid in 2019,the gray GM(1,N)model is optimized The relative error is reduced from 4.79%to 1.87%.This provides a new idea for accurately predicting the relative abundance of the squid resource.(3)This paper uses the Schaefer residual yield model as the main resource assessment model.First,combined with Bayesian methods,the resources of the Squid Squid in the South China Sea are evaluated by the uniform distribution scheme and the normal distribution scheme;secondly,the harvest rate is used as an indicator to establish the South China Sea The management index system of Squid Squid and corresponding management strategies were discussed.The results show that under the two scenarios,Squid resources in the South China Sea are in a sustainable development state from 2013 to 2019,and there is no phenomenon of overfishing.At this time,under the even distribution plan,The maximum sustainable output is 474,700 tons,and the resource amount is 937,550 tons;under the normal distribution scheme,the maximum sustainable output is 410,590 tons,and the resource amount is 874,900 tons.Through the risk analysis of the management strategy,it is found that the harvest will be harvested.The rate is maintained at 0.4.At the end of the management period,the best balance between the stock resources and the catch will be achieved.At this time,under the uniform distribution plan,the catch will reach 439,360 tons;under the normal distribution plan,the catch will reach 358,300 tons,and there will be no overfishing or resource collapse. |
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