Short-term change in fish assemblages after the passage of a typhoon in a temperate, coastal bay

Abstract

To study the effects of a typhoon on a temperate, coastal bay community, the species composition, catch amount, and diversity of epipelagic fish assemblages were investigated. Fish samples were taken from catches of a purse seine fishery in Tachibana Bay, Japan between May and July 2011, covering before and after the passage of a typhoon in the area. Although major changes in total catch amount were not observed before and after the passage of the typhoon, the abundance of the Japanese anchovy, Engraulis japonicus Temminck et Schlegel, 1846, markedly decreased and bycatch of species increased, accompanied by increasing levels of diversity of the fish assemblage. Multivariate analysis showed that community differences before and after the passage were quantitative rather than qualitative. Comparisons in total length frequencies between the two periods indicated that specimens of the species compared were bigger in size for Trachurus japonicus (Temminck et Schlegel, 1844) and smaller for E. japonicus in the “after” period. These results suggest that the passage of the typhoon triggered not only interspecific faunal change but also intraspecific recruitment shifts in and around the bay.

Distributional Changes in Fishery Resource Diversity Caused by Typhoon Pathways in the East/Japan Sea

“…These results are similar in Tachibana Bay [24]. After passing through the typhoon, the heat was transferred to a deeper layer.…”

“…These changes in the marine environment after a typhoon may directly or indirectly affect the structure of the marine ecosystem and the distribution of fishery resources [22,24,40]. The distribution of ectothermic animals, such as fish, requires water temperature conditions that can allow them to adapt to survival or environmental conditions and are favorable for feeding activities.…”

“…After passing through the typhoon, the heat was transferred to a deeper layer. Accordingly, the area or depth of different water temperatures was moved according to the habitat characteristics of Engraulis japonicus, Trachurus japonicus, and Sarda orientalis [24,62]. It is suggested that vertical mixing through the water column in the EJS dispersed the thermal energy of the upper layer to the deep layer, expanding the habitat of pelagic fish.…”

“…The stratification structure is weakened as typhoons stimulate primary production through the upward mixing of deep nutrients toward the surface [17][18][19][20][21]. Changes in the physical oceanic environment have resulted in changes in rapid primary productivity and food webs, which cause changes in the distribution, species diversity, and catchment of fishery resources [22][23][24][25][26].…”

“…Previous research has explained the oceanic condition change processes by which typhoons with strong physical forces pass through the EJS and have also focused on the short-term changes in Chl-a and the landing of pelagic fish [22,[24][25][26]. The typhoon strength and moving path were both found to be influencing factors; therefore, understanding the effects of typhoon path variations in the EJS on different marine environmental characteristics in each area and its impact on the distribution and diversity of marine life resources caused by the post-typhoon chain responses in marine ecosystems is crucial to understanding typhoon-induced changes in the EJS.…”