Institute of Fisheries Science, NTU

Research Interests:
(1) Eel population structure and biogeography
(2) Eel resource dynamics and conservation
(3) Eel sex and maturation
(4) Eel artificial propagation
(5) Anti-WSSV protein drug

(A) The Japanese eel (Anguilla japonica) is a temperate catadromous fish with a complex life cycle. We have used microsatellite DNA loci to clarify its population genetic structure (Han et al. 2010; Han 2012). Furthermore, no differences in habitat utilization or larval duration were found to contribute to the population structuring (Han et al. 2010). These results strongly suggest the existence of only a single panmictic population of Japanese eels. Thus, our findings have important implications for implementing a reasonable management program for the Japanese eel. Regulations must involve all East Asian countries to prevent further decline of this valuable eel resource. 

(B) Japanese eels spawn in restricted areas (12–16°N and 141–142°E) during a specific time period (June to August). For 3 months, the larvae are passively transported via the North Equatorial Current (NEC) to the eastern Philippines, and they later enter Kuroshio and its branch waters to reach their East Asian habitats (Han et al. 2012). The recruitment season starts in southern East Asia and ends in northern areas with a maximal time lag of ~5 months. The recruitment time lag to northern East Asia could be due to a longer leptocephalus stage (1–2 months) and a slower coastal current transportation (1–3 months). Glass eels could remain in the early pigmentation stage, while losing some body weight during lag recruitment (Han 2011). Since the leptocephali are passively transported by oceanic currents, and glass eel recruitment in Taiwan begins one to several months earlier than in other areas, the dynamics of glass eel recruitment in Taiwan may serve as a useful indicator of the subsequent glass eel recruitment in other locations.

(C) Since the 1970s, the loss of temperate-zone anguillid eels, particularly Anguilla anguilla, A. rostrata, and A. japonica, has exceeded 90% based on estimates of glass eel recruitment. In East Asia, the consequences of long-term habitat loss and deterioration of habitat quality on the sustainability of Japanese eel resources are important. We used chronological Landsat imagery to measure the reduction in Japanese eel habitat resulting from human activities in 16 rivers in East Asia, including Japan, Korea, Taiwan, and China. On average, 76.8% of the effective habitat area was lost in these 16 rivers from the 1970s to the 2010s (Chen et al. 2014). Taiwan and China had the highest percentages of habitat loss. Together with regional climate phenomena such as the ENSO and overfishing, extensive habitat loss may play an important role in the decline of the Japanese eel in East Asia. Therefore, measures targeting habitat restoration and protection may need to be integrated into management planning for Japanese eel resources within an international, rather than regional, context.

(D) In the past few decades, glass eel abundances have been declining significantly, which has severely impacted the condition of the eel aquaculture industry. Therefore, the culture of other eel species has become more and more popular in recent years. Several glass eel species are imported from other countries, including A. marmorata and A. bicolor pacifica. However, at present, the basic biological information of these aquaculture eel species is still poor. We obtained transcriptome data for four endemic eel species in Taiwan, namely A. japonica, A. marmorata, A. bicolor pacifica, and A. luzonensis, using the Illumina HiSeq 2000 platform. By Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, over 50% of the contigs were annotated and most were involved in KEGG metabolism pathways. This valuable information is useful for eel researchers.

近年重要著作 (2017- ):

*責任作者

Hsu HY, Chen HW, Han YS* (2019). Habitat partition and its possible genetic background between two sympatrically distributed eel species in Taiwan. Zoological Studies 58:27

Zhang B, Ye Y, Ye W, Perčulija V, Jiang H, Chen Y, Li Y, Chen J, Lin J, Wang S, Chen Q, Han YS, Ouyang S* (2019). Two HEPN domains dictate CRISPR RNA maturation and target cleavage in Cas13d. Nature Communication 10:2544 

Huang B, Wang ZX, Zhang C, Zhai SW, Han YS, Huang WS*, Nie P* (2019). Identification of a novel RIG-I isoform and its truncating variant in Japanese eel, Anguilla japonica. Fish & shellfish immunology 94: 373-380

Chen F, Lai F, Luo M, Han YS, Cheng H*, Zhou R* (2019) The genome-wide landscape of small insertion 1 and deletion mutations in Monopterus albus. Journal of Genetics and Genomics 46:75-86

Han YS*, Hsiung KM, Zhang H*, Chow LY, Tzeng WN, Shinoda A, Yoshinaga T, Hur SP, Hwang SD, Iizuka Y, Kimura S (2019). Dispersal characteristics and pathways of Japanese glass eel in the East Asian Continental Shelf. Sustainability 11(9): 2572

Chen F, Lai F, Luo M, Han YS, Cheng H*, Zhou R* (2019) The genome-wide landscape of small insertion 1 and deletion mutations in Monopterus albus. Journal of Genetics and Genomics 46:75-86

 Igarashi Y, Zhang H, Tan E, Sekino M, Yoshitake K, Kinoshita S, Mitsuyama S, Yoshinaga T, Chow S, Kurogi H, Shinoda A, Han YS, Wakiya R, Mochioka N, Yamamoto T, Kuwada H, Kaji Y, Suzuki Y, Gojobori T, Kobayashi T, Saitoh K, Watabe S, Asakawa S* (2018) Whole-genome sequencing of 84 Japanese eels reveals evidence against panmixia and support for sympatric speciation. GENE 9:474

Chen SC, Chang CR, Han YS* (2018) Seaward migration routes of Anguilla japonica, A. marmorata, and A. bicolor pacifica via satellite tags. Zoological Studies 57:21

Hsu HY, Chang FC, Wang YB, Chen SH, Lin CY, Han YS* (2018) Revealing the compositions of the intestinal microbiota of three Anguillid eel species by using 16S rRNA metagenomics. Aquaculture Research 00:1-12

Hsiung KM,* Kimura S, Han YS, Takeshige A, Ilzuka Y (2018) Effect of ENSO events on larval and juvenile duration and transport of the Japanese eel (Anguilla japonica). PLOS ONE 13(4):e0195544.

Chang YLK*, Miyazawa Y, Béguer-Pon M, Han YS, Ohashi K, Sheng J (2018) Physical and biological roles of mesoscale eddies in Japanese eel larvae 1 dispersal in the western North Pacific Ocean. Scientific Reports 8:5013

Lin YJ*, Tzeng WN, Han YS, Roa-Ureta RH (2017) A stock assessment model for transit stock fisheries with explicit immigration and emigration dynamics: application to upstream waves of glass eels. Fisheries Research 195: 130-140

Lin YF, Wu CR*, Han YS (2017) A combination mode of climate variability responsible for extremely poor recruitment of the Japanese eel (Anguilla japonica). Scientific Reports 7:44469

Hsu A*, Xue H, Chai F, Xiu P, Han YS (2017) Variability of the Pacific North Equatorial Current and its implications on Japanese eel (Anguilla japonica) larval migration. Fisheries Oceanography doi:10.1111/fog.12189