Vol. 57, 2018 (update: 2018.04.25; 05.24) Seaward Migration Routes of Indigenous Eels, Anguilla japonica, A. marmorata, and A. bicolor pacifica, via Satellite TagsShih-Chong Chen1, Ching-Rong Chang1, and Yu-San Han1,* doi:10.6620/ZS.2018.57-21
1Institute of Fisheries Science, College of Life Science, National Taiwan University, Taiwan. E-mail: f05b45011@ntu.edu.tw (Chen); jackyto888@gmail.com (Chang) (Received 16 November 2017; Accepted 11 April
2018; Communicated by Hin-Kiu Mok) Shih-Chong
Chen, Ching-Rong Chang, and Yu-San Han (2018) The spawning
migration of the Japanese eel, Anguilla
japonica, along the western
Mariana Ridge is considered one of the longest animal migrations. To
establish an appropriate conservation policy for this species, a
complete life cycle study is required, but the migratory routes of
anguillid eels remain poorly documented. Anguilla japonica, A.
marmorata, and A. bicolor
pacifica are three common eel species in
Taiwan. The present study used pop-up archival transmitting tags to
track their movements during the oceanic phase of their migration.
Twenty silver eels (farmed and wild) were tagged and released near the
Gueishan and Liuchiu Islands. All three species in the Gueishan Island
group were entrained in the Kuroshio Current, andpop-up tag data showed
that, after 23 days, the farthest distance travelled was approximately
1,500 km, to the southern waters of Yakushima, Japan. In comparison,
eels released near Liuchiu Island moved in the opposite direction,
which suggests that they were influenced by the recirculation in the
southwestern waters of Taiwan. The migration speed of eels was
estimated to be between 12.9 km/d and 65.2 km/d. Several eels exhibited
diel vertical migration behavior, moving into deeper water during the
daytime and ascending into shallower waters at night. The farmed eels
exhibited similar patterns of diel vertical migration to wild eels. The
results of this study suggest that eels from Taiwan travel through the
Kuroshio Current during their early migration, irrespective of species
and source. Of importance, farmed eels appeared to behave similar to
wild ones following artificial release. This information provides
important rationale for releasing cultivated eels for resource
enrichment programs. provided. Key words: Eel, Spawning
migration, Pop-up archival transmitting tag, Diel vertical migration,
Kuroshio Current. *Correspondence: Shih-Chong Chen and Ching-Rong
Chang contributed equally to this work. E-mail: yshan@ntu.edu.tw |