Distribution and growth of Scomber japonicus and S. australasicus larvae in the southern East China Sea in response to oceanographic conditions

Abstract

Chub mackerel Scomber japonicus and spotted mackerel S. australasicus are important fishery resources in the countries adjacent to the East China Sea (ECS). During February to March in 2004 and 2005, based on species identification using PCR-restriction fragment length polymorphism (PCR-RFLP) analysis of mtDNA, we examined the larval distribution, transport and growth of both species in the southern ECS, where extremely high abundances of Scomber spp. larvae are found. Distribution of S. australasicus was in a more southern area than was S. japonicus, with a higher and narrower range of habitat temperature (20 to 23°C versus 15 to 22°C), although there was some spatial overlap. In 2004, when an intrusion of the warm Kuroshio Branch Current north of Taiwan was evident, S. australasicus were transported northeastward, while they dispersed eastward along the Kuroshio front in 2005 when the intrusion was weak. Although S. japonicus showed a similar pattern of transport and dispersal to S. australasicus, it was more gradual, corresponding with the weaker flow in the northern part of the study area. The daily specific growth rates of S. japonicus and S. australasicus were 6.2 to 8.2% and 7.7 to 9.3% of body length per day, respectively, and growth was significantly higher in 2004 than in 2005 for both species, with both habitat temperature and food availability being higher in 2004. Our study provides fundamental information on the spawning and recruitment of these 2 mackerel species on which to base predictive models, which are essential for protecting these shared stocks that migrate across the boundaries within the ECS.

Larval fish assemblages in the Taiwan Strait, western North Pacific: linking with monsoon‐driven mesoscale current system

“…, 2004) or the transport and dispersal of larvae (Franco‐Gordo et al. , 2003; Sassa and Tsukamoto, 2010) of the different species, other oceanographic variables also affected the distribution pattern of larval fish. Most research on larval fish assemblage in different regions of the world has shown the influences of bathymetry and spawning grounds of adults on the spatial distribution patterns (Olivar, 1990; Muhling et al.…”

“…Kuroshio Branch Current, and South China Sea Surface Current were detected between seasons. With the ordination analysis of the dominant taxa (CCA diagram), we found that the abundances of most dominant species were closely related to the abundance of chlorophyll a and zooplankton, indicating that in addition to the importance of seasonality in regulating community structure by the reproduction periods (Gray and Miskiewicz, 2000;Koutrakis et al, 2004) or the transport and dispersal of larvae (Franco-Gordo et al, 2003;Sassa and Tsukamoto, 2010) of the different species, other oceanographic variables also affected the distribution pattern of larval fish. Most research on larval fish assemblage in different regions of the world has shown the influences of bathymetry and spawning grounds of adults on the spatial distribution patterns (Olivar, 1990;Muhling et al, 2007).…”

Species composition and assemblages of ichthyoplankton during summer in the East China Sea

“…In contrast, directly investigating the spatial and temporal distributions of fish eggs and larvae is an ideal alternative. Since diverse fish eggs and larvae can be captured through zooplankton net sampling, researchers can more easily and precisely identify the spawning and nursery grounds and the spawning period through ichtyoplankton assessments (Sassa and Tsukamoto, 2010;Ellis et al, 2012;Hsieh et al, 2012).…”

Ichthyoplankton Detection Proportion and Margin of Error for the Scomber japonicus in Korean Coastal Seas

“…The larvae of S. japonicus start to appear from March off Jeju Islands (Yoo 1991). These larvae could be transported by the Kuroshio Currents at the end of February or in the beginning of the March from the northern seas of Taiwan in the South China Sea (Sassa and Tsukamoto 2010). However, the main stream of the Kuroshio Current does not directly flowing into the Korean coastal seas.…”