1. Where are you from? A case study of Japanese Spanish mackerel using Anisakis third-stage larvae as a biological tag in coastal northeast Aomori Prefecture, Japan.
- Author
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Tanaka, Yuuki and Ohshimo, Seiji
- Subjects
BIOLOGICAL tags ,ANISAKIS ,TRADE routes ,AUTUMN ,MACKERELS - Abstract
The distribution of Japanese Spanish mackerel Scomberomorus niphonius (JSM) has been expanding in coastal Japan since the 2000s. We investigated the expansion routes into the Pacific Ocean using Anisakis third-stage larvae (L3) as a biological tag. Two hypotheses were considered for the expansion routes: (1) JSM migrating north along the Pacific coast of Japan, and (2) JSM migrating from the Sea of Japan through the Tsugaru Strait to the Pacific Ocean. To test these hypotheses, young-of-the-year JSM were collected during autumn from 2019 to 2023 in both the Sea of Japan and the Pacific Ocean. Anisakis larvae were extracted from these specimens. We collected 50 JSM from the Sea of Japan and 67 from the Pacific, from which 66 and 246 Anisakis larvae were extracted, respectively. Species identification using PCR-based restriction fragment length polymorphism revealed that over 90% of the Anisakis from both regions were Anisakis pegreffii, a species known to inhabit the Sea of Japan. This provides strong supporting evidence that JSM migrates from the Sea of Japan through the Tsugaru Strait into the Pacific Ocean. Furthermore, we confirmed that individual JSM harbored up to 106 parasites. The presence of such a high abundance suggests that these individuals may have originated from the East China Sea, the source of infection, and migrated to the capture area just before being caught. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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