| 要旨トップ | 目次 | 日本生態学会第67回全国大会 (2020年3月、名古屋) 講演要旨
ESJ67 Abstract


一般講演(口頭発表) J01-04  (Oral presentation)

Linking fish population spatial variability to age-specific habitat preference: an individual-based model approach

*Hsiao-hang TAO(National Taiwan University), Gaël DUR(Shizuoka University), Sami SOUISSI(Université de Lille, Station Marine de Wimereux), Chih-hao HSIEH(National Taiwan University)

High variation in population spatial distribution (i.e. less homogeneous spatial distribution) undermines population stability and resilience to a changing environment. Empirical studies suggest that sized-selective fishing contributes to age truncation, which in turn elevates population spatial variability for multiple fish species. We hypothesize that age-specific habitat preference (ontogenetic niche shift in habitat) contributes to such pattern. That is, different age classes of a fish population have distinct habitat choices. Size-selective fishing results in more right-skewed demography, which in turn increases the overall spatial patchiness (i.e. spatial heterogeneity) of the population. We further hypothesize that such effect is more pronounced when the population has a stronger age-specific habitat preference. To test these hypotheses, we devise a spatially-explicit, age-structured, multi-generational individual-based fish population model. Individual fish has either strong or weak age-specific habitat preferences. Survival rates of older age classes decrease with increasing fishing intensities. Supporting our hypothesis, spatial variability (coefficient of variation) increases with reducing age diversity (Shannon index), indicating fishing-induced age truncation elevates spatial variability. Furthermore, the sensitivity of spatial variability to age diversity is higher for population with stronger age-specific habitat preference. The differences in the sensitivity decrease with increasing carrying capacity and patchiness of habitat configuration.


日本生態学会