Spatial distribution and inter-annual variability of spawning grounds of Cynoglossus joyneri in the Yellow Sea coastal waters in summer

Abstract

With survey data from three voyages in the summer of 2014, 2016, and 2017, spatial distribution and inter-annual variability of spawning grounds of Cynoglossus joyneri in the coastal waters of Yellow Sea were examined based on Tweedie-generalized additive model (GAM). The results showed that the spawning grounds of C. joyneri mainly distributed in the Haizhou Bay ranging within 34°00'-35°18' N, 119°30'-121°30' E. The other one in Subei Shoal 32°18'-34°00' N, 120°18'-122°00' E. Fish eggs of C. joyneri were few in the southern waters of Shandong Peninsula 34°42'-36°48' N, 119°30'-122°00' E. The distribution of fish eggs was significantly related to the location (i.e., longitude and latitude), depth, and sea surface temperature, and did not relate to the sea surface salinity and surface chlorophyll a. The optimal range of depth, sea surface temperature, sea surface salinity, and surface chlorophyll a were 15-26 m, 29-32 ℃, 22-25 and 0.10-3 mg·m-3, respectively. There was notable inter-annual variability in the spatial distribution of spawning grounds of C. joyneri and its influencing factors. Overall, the distribution of spawning grounds is relatively stable, but potentially move northward in the year with high sea surface temperature.