Effects of oceanographic environment on the distribution and migration of Pacific saury (Cololabis saira) during main fishing season

Abstract

The Pacific saury (Cololabis saira) is one of the most commercially important pelagic fishes in Asia–Pacific countries. The oceanographic environment, especially the Oyashio Current, significantly affects the distribution of Pacific saury, and may lead to variations in their migration route and the formation of fishing grounds in Japanese coastal region and the high seas. In this study, six oceanographic factors, sea surface temperature (SST), sea surface chlorophyll-a concentration (SSC), sea surface salinity (SSS), sea surface height (SSH), mixed layer depth (MLD), and eddy kinetic energy (EKE), were associated with the monthly catch per unit effort 1 (monthly CPUE1, ton/vessel) and the monthly CPUE2 (ton/day) of Pacific saury from Chinese fishing vessels during the optimal fishing periods (September–November) in 2014–2017. The gradient forest analysis showed that the performance of monthly CPUE1 was higher than monthly CPUE2 and SST was the most important oceanographic factor influencing monthly CPUE1, followed by EKE. The generalized additive model indicated that SST, SSH, and EKE negatively affected monthly CPUE1, whereas SSC, SSS, and MLD induced dome-shaped increases in monthly CPUE1. The distributions of fishing locations are likely to form along Offshore Oyashio current and meanders, especially in October and November. Synchronous trends in the relationship between the intrusion area of the Oyashio and relative abundance variation index suggest that an increase in the intrusion area of the Oyashio causes more Pacific saury to migrate to the Japanese coastal region, and vice versa. These findings extend our understanding of the effects of the oceanographic environment on Pacific saury.

Biological interactions potentially alter the large-scale distribution pattern of the small pelagic fish, Pacific saury Cololabis saira

“…In particular, the Isoguchi Jet (Isoguchi et al 2006), which is a quasi-stationary jet that separates from Kuroshio currents and extends northward, has a strong influence on the feeding environment for pelagic fishes in this area (Miyamoto et al 2022). Various environmental factors that were suggested to be important for the distribution of Pacific saury, such as SSS, SSH, SSTG, and chl a, should be related to currents in this area (Chang et al 2019, Hua et al 2020, Liu et al 2022, Xing et al 2022). Long-term interannual variations in the current speed of the Isoguchi Jet (e.g.…”

“…Tseng et al 2013, Chang et al 2019, Hua et al 2020, Hsu et al 2021. In recent years, some studies have compared the relative importance of various environmental variables on Pacific saury distribution and found that SST and SSTG are more influential than other factors (Chang et al 2019, Liu et al 2022Xing et al 2022. Hence, we focused on the distribution pattern of Pacific saury and other species along the SST gradient in this study because SST is one of the most important factors explaining the distribution of not only Pacific saury (e.g.…”

“…Hence, we focused on the distribution pattern of Pacific saury and other species along the SST gradient in this study because SST is one of the most important factors explaining the distribution of not only Pacific saury (e.g. Liu et al 2022, Xing et al 2022) but also other marine species including chub mackerel, Japanese sardine, and Japanese anchovy (Dambach & Rödder 2011, Murase et al 2012, Yasuda et al 2014, Muko et al 2018, Hashi moto et al 2019, Melo-Merino et al 2020.…”

Large scale eDNA database reveals latitudinal diversity gradients with seasonal variations

“…In such a case, we should have observed latitudinal lines with a more gradual slope in summer and a steeper slope in winter. To examine the seasonal migration pattern of fish, we visualized the seasonal distribution patterns of Cololabis, Sardinops, Scomber, Seriola and Trachurus, which are genera widely distributed in Japan and have relatively well-known seasonal migration patterns [34,[39][40][41][42][43] (northwards in summer and southwards in winter). In contrast to the well-known seasonal migration, the distributions exhibited unclear seasonal differences (Figure S2).…”

Modeling of swordtip squid (Uroteuthis edulis) monthly habitat preference using remote sensing environmental data and climate indices

“…Haghi Vayghan et al 10.3389/fmars.2024.1329254 whereas the main prey of the adult squid is small pelagic fishes. Furthermore, studies have applied primary production data sets in habitat models to evaluate habitat preferences and main fishing grounds in different ecosystem (Liu et al, 2022;Mammel et al, 2022;Mondal et al, 2022;Mondal et al, 2023;Teng et al, 2021;Vayghan and Lee, 2022;Semedi et al, 2023;Zarkami et al, 2023).…”