Vol. 58, 2019

(update: 2019.07.23; 09.18)
 

Habitat Partitioning and its Possible Genetic Background Between Two Sympatrically Distributed Eel Species in Taiwan

Hsiang-Yi Hsu^1,§, Hsiao-Wei Chen^1,§, and Yu-San Han^1,*

¹Institute of Fisheries Science, College of Life Science, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei 106, Taiwan. *Correspondence: E-mail: yshan@ntu.edu.tw. Tel: 886-2-3366-3726. Fax: 886-2-3366-9449

^§HYH and HWC contributed equally to this work.
Received 19 April 2019 / Accepted 19 July 2019
Communicated by Yasuyuki Hashiguchi

The geographical distributions of the Japanese eel (Anguilla japonica) and Giant-mottled eel (A. marmorata) overlap in many regions in East Asia and therefore suffer from interspecific competition in the same rivers. After a long period of adaptation, the Japanese eel and Giant-mottled eel may exhibit habitat partitioning in the rivers to diminish the interspecific competition between them. In this study, we conducted a field investigation in the Fengshan River in Taiwan to survey the habitat distributions of the Japanese eel and Giant-mottled eel throughout a river. Moreover, we investigated whether their habitat distributions are related to their swimming and upstream migration. Thus, the mRNA expression levels of several candidate genes that may be associated with the swimming and upstream migration of eel were examined in the glass eels of the Japanese eel and Giant-mottled eel. Field investigation indicated that the Japanese eel mainly inhabited the lower and middle reaches of the Fengshan River, but the Giantmottled eel was distributed over the middle to upper reaches. The mRNA expression levels of fMYH, dio2, gria3, and neurod1 were higher in the Giant-mottled eel than in the Japanese eel, implying that Giantmottled eels might have better swimming bursts and more active upstream migration than Japanese eels. These results suggest that there is a habitat partition at which these two eel species coexist in a river, and their habitat distributions may be linked to their swimming bursts and upstream migration. Determining the habitat distributions of freshwater eels is important for developing applicable plans for eel conservation and resource management.

Key words: Giant-mottled eel, Habitat partitioning, Interspecific competition, Japanese eel and upstream migration.

Citation: Hsu HY Chen HW, Han YS. 2019. Habitat partitioning and its possible genetic background between two sympatrically distributed eel species in Taiwan. Zool Stud 58:27. doi:10.6620/ZS.2019.58-27.

Supplementary Materials: Table S1 | Table S2 | Table S3