Distribution and reproductive aspects of the pandalid shrimp,Pandalus eous,in the deep sea of the East Sea, Korea

Abstract

The objective of the study was to investigate if reproductive characteristics of Pandalus eous affect the depth distribution in the East Sea of Korea. P. eous was found at depths of 500Á900 m in the East Sea of Korea, with the highest percentage occurrence (34%) at 500 m. A negative correlation was observed between the number of individuals and the depth. The overall sex ratio also turned out to be significantly correlated with depth. On average, the larger individuals (bigger than 26.37 cm), which included transitional, female, and ovigerous females, were mostly distributed at 700 m depth. The percentage of males increased by depth and ovigerous females were mainly distributed in the shallow water (300 m) during winter.Ovigerous females were not found at 900 m, which is the deepest depth range in this study. The percentage of transitional individuals was greatest at 500 m and decreased gradually with depth. All ovigerous female individuals were of the spent ovarian stage in winter. Female numbers in the ripe ovarian stage increased with depth and immature females rarely appeared. The gonadosomatic indices of the nonovigerous females and ovigerous females were highest at 700 m in depth. The mean egg size of P. eous was 0.8390.11 mm 3 in the nonÁeyed stage and 0.9390.17 mm 3 in the eyed stage.

Diet composition and feeding strategy of John Dory, Zeus faber, in the coastal waters of Korea

“…We found that crustaceans were the dominant species in summer and autumn in this study because of the behavior and life history of crustacean prey (Xue et al 2005;Blasina et al 2010). P. eous used as prey mainly migrate to inshore (< 50 m) for the larval hatch during late winter and early spring (Park et al 2012;Richards 2012). The density of crustaceans increases as the hatched crustaceans recruit in summer.…”

“…The density of crustaceans increases as the hatched crustaceans recruit in summer. Also, P. eous can be captured more than other invertebrates because P. eous inhabit in various water depths up to 600 m deep (Park et al 2012). Therefore, larger individuals of Z. faber inhabit in deeper depths and can consume crustaceans abundantly.…”