Research Report
Whale shark migration route survey
Why is it necessary to investigate Whale shark migration routes?
Whale shark are an endangered species designated as "endangered" on the IUCN (International Union for Conservation of Nature) Red List, but much of their ecology remains a mystery, and there is a lack of ecological information needed for conservation, such as their habitat, migration routes, and population size.
Kaiyukan is the only aquarium in Japan that breeds and exhibits Whale shark, and since 2011 has been collaborating with Hokkaido University to research the migration routes of Whale shark. The continued research will hopefully contribute to the conservation of this endangered Whale shark.
What kind of creature is a Whale shark?
It is the largest fish in the world, with a maximum total length of 10-12 metres and is thought to grow even larger in rare cases.
It is characterized by white spots on its back, and in spite of its large size, it mainly feeds on plankton such as small crustaceans. It inhabits coastal and open ocean waters from temperate to tropical regions, and can be found in the waters off Japan from early summer to autumn.
Since its opening in 1990, Kaiyukan has been raising and exhibiting Whale shark.
Scientific name: Rhincodon typus
Research Methodology
A technique called biologging is used to investigate migration routes.
Biologging is a research technique in which seawater is used to raise living creatures, and a small recording device (data logger) is attached to the creatures, and the behavior that the creatures (bio) record (log) is analyzed. Research is being conducted around the world on a variety of living creatures.
Records of migration routes, water depth, water temperature, etc. are collected.
The data recorded is acquired via satellite and then analyzed.
Past survey results report
To date, 12 surveys have been conducted and record data has been successfully obtained in four cases.
*The recorded data from three surveys conducted between 2023 and 2024 is currently being analyzed.
We know that whale sharks migrate from the waters off Japan to Southeast Asia and dive to depths of over 1,500 meters, but the results vary from individual to individual. We believe that by accumulating data, we can get closer to understanding the ecology of Whale shark.
It is known that they also swam in the deep sea at depths of around 1,600m.
| year | start date | period | Maximum diving depth | Migration route |
|---|---|---|---|---|
| 2011 | Data not available | |||
| 2012 | Ibid. | |||
| 2013 | October 14th | 1 month | 632m | From off the coast of Iburi, Kochi Prefecture to the north, off the coast of Chiba |
| 2014 | June 13th | 3 months | 1,560m | After moving north from off the coast of Iburi, Kochi Prefecture to the coast of Tohoku, it moved south to the coast of Chiba Prefecture. |
| 2015 | October 13 | 6 months | Depths of 1,500m or more | It moves east from off the coast of Iburi, Kochi Prefecture, then turns south near where it joins the Kuroshio Current and travels south to the southern Philippines, then travels north to the northern Philippines, then turns south again. |
| 2016 | Data not available | |||
| 2017 | Ibid. | |||
| 2018 | Ibid. | |||
| 2022 | June 27 | 1 month | Approximately 1,500m | From Muroto, Kochi Prefecture to the north off the coast of Chiba Prefecture |