夏季西南大西洋阿根廷无须鳕异尖线虫幼虫感染情况研究OA北大核心CSTPCD

Merluccius hubbsi is one of the most prominent fishing species in the southwestern Atlantic Ocean,and its catch has been increasing continuously in recent years.Owing to its delicate taste and rich nutritional value,it is very popular among nationals and is one of the major chilled fish imported in China.Anisakid larvae are one of the most common parasites of Merluccius hubbsi.Available data show that its infection rate can be as high as 90%or more,and the intensity of the infection is also high.Parasite infection not only draws nutrients from the host fish but also affects the aesthetics of the fish and reduces its economic value.This study aimed to understand the infection of M.hubbsi by anisakid larvae in the waters of the Southwest Atlantic,to perform biological experiments on M.hubbsi,to collect parasites for morphological identification,and to record and analyze the data.Samples for this study were collected from sampling sites in open ocean waters outside the exclusive economic zone of Argentina and the Malvinas Islands during the summer months of October 2022 to February 2023,with a total of 435 individuals.The results showed that the infection rate of M.hubbsi infected by anisakid larvae was 99.08%and the mean intensity of infection was(19.56±24.76)fish/tail.The higher the sexual maturity of M.hubbsi,the higher the mean intensity of infection of anisakid larvae was;the mean intensity of infection of anisakid larvae was as high as(50.61±56.78)fish/tail when sexual maturity was stage IV.The sites of infection of anisakid larvae were the abdominal cavity,liver,and stomach.The infection intensity of anisakid larvae was significantly higher in the abdominal cavity and liver than at other sites(P<0.05).This study showed that the abundance and intensity of M.hubbsi infection by anisakid larvae in the Southwest Atlantic was high,which was related to the stable ecosystem of its living sea area,large host population size,and suitable environment for survival.As the host matures,the range and number of feeding objects increase,and the parasite accumulates in the host during this process;it mainly parasitizes the abdominal cavity where the environment is suitable and the area of parasitism is large,and the liver and stomach,which have high nutritional value,are suitable for its growth,development,and stable parasitism.In summary,the number of M.hubbsi infected with anisakid larvae was related to sexual maturity and different infection sites in the sample fish,and the number of infections was correlated with fork length and body weight.This study provides a basis for understanding the growth characteristics and factors influencing anisakid larval infection of M.hubbsi.