１. Key point
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- For nearly 100 years, the Sargasso Sea has been regarded as the spawning area of Atlantic eels; however, the exact location of the spawning area remains a mystery.
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- Larval migration simulations using ocean current data suggested, for the first time to our knowledge, that the spawning area may lie near the seamounts in the Mid-Atlantic Ridge on the eastern side of the Sargasso Sea.
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- The Mid-Atlantic Ridge has yet to be thoroughly surveyed, and advancements in research through future field surveys are highly expected.
2. Overview
Our joint research team comprising researcher Yu-Lin K. Chang, deputy director Yasumasa Miyazawa (Application Laboratory, Research Institute for Value-Added-Information Generation, Japan Agency for Marine-Earth Science and Technology), Professor Eric Feunteun (Muséum National d’Histoire Naturelle, France), and Professor Katsumi Tsukamoto (Department of Aquatic Bioscience, The University of Tokyo) identified, for the first time to our knowledge, the seamounts in the Mid-Atlantic Ridge as a possible spawning area of Atlantic eels (Fig. 1, *1).
For nearly 100 years, the Sargasso Sea has been regarded as the spawning area of Atlantic eels; however, eggs and spawning adult eels have yet to be directly observed in this area. Meanwhile, the seamounts in the Mariana Ridge have been confirmed as the spawning area of Japanese eels. While searching for a marine area with similar characteristics in the Atlantic Ocean, our research team identified marine area X located north and south of the Mid-Atlantic Ridge, where sudden changes in water temperature and salinity characteristics were observed (15-29°N, 43-48°W; Fig. 2). We performed a larval migration simulation using ocean current data with sea area X as the spawning area, and were able to explain the spatial distribution of larvae collected so far (Figs. 3 and 4). Located on the eastern side of the Sargasso Sea, sea area X has yet to be subjected to a full-scale survey. With this in mind, we anticipate that future surveys will lead to advancements in research.
The results of this study were published in Scientific Reports on October 6 (Japan Standard Time).
- Title：
- New clues on the Atlantic eels spawning behavior and area: The Mid Atlantic Ridge Hypothesis
- Authors：
- Yu-Lin K. Chang1, Eric Feunteun2, Yasumasa Miyazawa1, Katsumi Tsukamoto3
- Affiliations：
- 1 Japan Agency for Marine-Earth Science and Technology (JAMSTEC)
2 Museum National d'Histoire Naturelle, Laboratory BOREA, (Biologie des Organismes et Ecosystèmes Aquatiques), Center of research on coastal ecosystems (CRESCO), Dinard, France
3 Department of Aquatic Bioscience, The University of Tokyo,
Fig. 1 Photograph of Atlantic eel (European eel). (C) E. FEUNTEUN MNHN
Fig. 2 (Top) Atlantic Ocean bathymetry. The Mid-Atlantic Ridge extends north to south from the waters of the Azores. The white dotted box indicates sea area X. The magenta circle indicates the area where European eel larvae have been observed, whereas the green circle indicates the area where American eel larvae have been observed. The white lines represent the areas with sudden changes in water temperature, whereas the yellow line represents the area with sudden changes in salt content. (Bottom) Average distribution of surface currents in the Atlantic Ocean. Color shades indicate the strength of ocean currents.
Fig. 3 Results of virtual particle tracking simulation assuming that the swimming speed of virtual particles (eel larvae) is zero. Colors correspond to latitude zones in sea area X where the particles are released. This is a composite of simulation results conducted annually from 1993 to 2000.
Fig. 4 Results of virtual particle tracking simulation assuming northwestward swimming speed (left) and northeastward swimming speed (right) of virtual particles.
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