Analysis of the Effect of White Spot Syndrome Virus (WSSV) on Shrimp Biomass in the Yellow Sea and the Northern East China Sea Based on GFM and GAMM Models

Abstract:

Shrimp plays a key role in the functional group of marine ecosystems, and its biomass is affected by multiple factors. Based on an epidemiological survey of white spot syndrome virus (WSSV) in wild shrimp in the Yellow Sea and the northern East China Sea, the impact of WSSV prevalence on the biomass of shrimp in these regions from 2016 to 2018 was analyzed using the gradient random forest model (GFM) and generalized additive mixed models (GAMM). The results of molecular detection showed that 11 out of 26 species of shrimp obtained in the survey were determined to be WSSV-positive; the percentage of WSSV-positive sites in 2016, 2017, and 2018 was 48.40%, 38.75%, and 21.74%, respectively. The percentage of WSSV-positive samples was 16.86%, 9.60%, and 4.80% in 2016, 2017, and 2018, respectively. The GFM analysis results showed that the explanatory variable "logarithm of the number of positive samples (ln_posi)" showed the highest priority to the response variable "logarithm of the shrimp biomass (ln _Abu)". The GAMM model analysis results showed that the optimal model selected according to the minimum principle of Akaike information criterion (AIC) was ln_Abu ~ WSSV positive rate (P_rate) + ln_posi+longitude (Long), in which the ln_posi and P_rate were crucial factors affecting the biomass of shrimp, and the biomass of shrimp decreased with the increase in WSSV positive rate. The above results revealed that the WSSV was prevalent in the shrimp of the Yellow Sea and the northern East China Sea, and will have a potential impact on the biomass of shrimp.