Institute of Fisheries Science, NTU

Research Interests:
(1) Fishing-induced changes in adult length for the pacific bluefin tuna
(2) Life history variation for subtropical cutlassfish
(3) Variation in offspring size and number
(4) Diverse temperature effects on the early life growth of cutlassfish
 

1. FISHING-INDUCED CHANGES IN ADULT LENGTH FOR THE PACIFIC BLUEFIN TUNA
Size-selective fishing tends to remove large and old individuals from fish populations, resulting in a truncated demographic structure. However, for the Pacific bluefin tuna Thunnus orientalis, which has been over exploited, the mean length and age of adult fish have been increasing. By constructing an individual-based model (IBM), we show that such increasing trends of fish size may result from the fishing effects mediated by size-dependent selection of skipped spawning (Wang et al. 2017). 
 
2. LIFE HISTORY VARIATION FOR SUBTROPICAL CUTLASSFISH
Spatial variation in con-specific growth rates implies differential population dynamics and likely distinct population structures. Here, we investigate growth variation for the exploited cutlassfish Trichiurus japonicus between two coasts of Taiwan (lat 22.5-25°N). Although variation in environmental conditions between the two coasts was subtle, we found significant differences in demographic structure and male growth rates of cutlassfish. The data suggest that the population that displays a slower growth rate may experience higher mortality, a pattern consistent with fishing-induced evolution on growth (Wang and Heino 2018).
 
3. VARIATION IN OFFSPRING SIZE AND NUMBER
Life history theory predicts that females should adjust sizes and number of offspring to maximize offspring survival probability based on environmental conditions. Subtropical fish tend to spawn in various seasons. We hypothesize that offspring (egg) size and number change among different seasons. We conduct a field experiment to evaluate this hypothesis based on cutlassfish Trichiurus japonicus. In addition, we conduct a rearing experiment using mosquitofish Gambusia affinis to explore the effects of maternal growth on offspring size and number.
 
4. DIVERSE TEMPERATURE EFFECTS ON THE EARLY LIFE GROWTH OF CUTLASSFISH
Temperature variability over the prolonged spawning time may lead to variable larval growth and survival for subtropical fishes. To test this hypothesis, we examined temperature effects on early life growth rates of cutlassfish, Trichiurus japonicus, which spawn all-year-round among 3 coasts of Taiwan. We found diverse temperature effects on early life growth rates: positive effect in NW but no clear linear effects in NE and SW coasts. Such differences may reflect differential temperature-induced trophic dynamics among coasts.

近年重要著作 (2017- ):

Lin, H. C., C. J. Tsai, and H.-Y. Wang (2021) Variation in global distribution, population structures, and demographic history for four Trichiurus cutlassfishes. PeerJ, 9, e12639.

Shimadzu, H. and H.-Y. Wang (2021) Estimating allometric energy allocation between somatic and gonadic growth. Methods in Ecology and Evolution, DOI: 10.1111/2041-210X.13761.

Wang, H.-Y., S.-F. Shen, Y.-S. Chen, Y.-K. Kiang, and M. Heino (2020) Life histories determine divergent population trends for fishes under climate warming. Nature Communications, 11: 4088.

Wang, H.-Y., L. M. Tsang, F. P. Lima, R. Seabra, M. Ganmanee, G. A. Williams, and B. K. K. Chan (2020) Spatial variation in thermal stress experienced by barnacles on rocky shores: the interplay between geographic variation, tidal cycles, and microhabitat temperatures. Frontiers in Marine Science, 7: 553. doi: 10.3389/fmars.2020.00553

Gao, J., J. T. Thorson, C. Szuwalski, and H.-Y. Wang (2020) Historical dynamics of the demersal fish community in the East and South China Seas. Marine and Freshwater Research, 71(9): 1073-1085.

Chen, Y. S., Z. Y. Jeng, and H.-Y. Wang (2020) Changes in reproduction for subtropical cutlassfish Trichiurus japonicus reflect variation in temperature and population demography. Marine Ecology, e12578.

Denis V., J. W. Chen, Q. Chen, Y. E. Hsieh, Y. V. Lin, C. W. Wang, H.-Y. Wang, and N. Sturaro (2019) Biogeography of functional trait diversity in the Taiwanese reef fish fauna. Ecology and Evolution, 9(1): 522-532.

Wang, H.-Y. and M. Heino (2018) Adaptive and plastic variation in growth and maturation in the cutlassfish Trichiurus japonicus in subtropical Pacific. Fishery Bulletin 116: 171-182.

Lavoue, S., J. A. M. Bertrand, H.-Y. Wang, W.-J. Chen, H. C. Ho, H. Motomura, H. Hata, T. Sado, and M. Miya (2017) Molecular systematics of the anchovy genus Encrasicholina in the Northwest Pacific. PLoS One, 12 (7): 0181329.

Shiao, J. C., H. B. Lu, J. Hsu, H.-Y. Wang, S. K. Chang, M. Y. Huang, and T. Ishihara (2017) Changes in size, age, and sex ratio composition of Pacific bluefin tuna (Thunnus orientalis) on the northwestern Pacific Ocean spawning grounds. ICES Journal of Marine Science, 74 (1): 204-214.

Wang, H.-Y., C. A. Dong, and H.-C. Lin (2017) DNA barcoding of fisheries catch to reveal composition and distribution of cutlassfishes along the Taiwan coast. Fisheries Research 187: 103-109.

Wang, H.-Y., Y.-S. Chen, C.-C. Hsu, and S.-F. Shen (2017) Fishing-induced changes in adult length are mediated by skipped-spawning. Ecological Applications, 27 (1): 274-284.