Density Estimation of an Euphauiid (Euphausia pacifica) in the Sound Scattering Layer of the East China Sea

Autor: Iida Kohji, Yoon Yang-Ho, Kim Yong-Ju, Suh Hae-Lip, Kang Donhyug, Shin Hyun-Chul, Hwang Doojin, Soh Hoyoung
Rok vydání: 2003
Předmět:
Zdroj: Korean Journal of Fisheries and Aquatic Sciences. 36:749-756
ISSN: 0374-8111
DOI: 10.5657/kfas.2003.36.6.749
Popis: Hydroacoustic and open-closing zooplankton net survey were conducted to understand the characteristics of the sound scattering layer (SSL) and to estimate the density of an euphausiid (Euphausia pacifica) in the SSL, in the northwestern part of the East China Sea. The survey was carried out during July 6-9 2002 at 8 sampling stations for zooplankton. The virtual echogram technique was used to identify E. pacifica from all acoustic scatters. Mean volume backscattering strength difference and target strength equation for E. pacifica were derived from the Distorted-wave Born Approximation (DWBA) model. Although vertical migration of the SSL is similar to the general pattern, dispersion at night shows some differences. Estimated mean density using acoustic data ranged from over the whole depth, and in the SSL. The density using the zooplankton net ranged from and was not related to net deploying method. The results from the acoustic and net survey suggest that E. pacifica might be an important zooplankton community in the northwestern part of the East China Sea.
Databáze: OpenAIRE