동해 후포주변 사질조하대에 서식하는 대형저서동물군집의 분포특성

Abstract

Distribution patterns of sandy bottom macrobenthic communities were studied around the Hupo coastal area. The seasonal surveys were conducted at 15 chosen sites within a depth range of 10 to 50 m along 10 ㎞ of the coastline using a Smith-McIntyre grab (0.05 ㎡) in 2005. Overall depth distribution following the direction of the offshore become deeper parallel to the coastline. A total of 319 macrobenthic species were sampled with a mean density of 1,972 ind./㎡, and mean biomass was 82.5 wet-weight g/㎡. The major individual-dominant species were three polychaetes Spiophanes bombyx (436 ind./㎡), Scoletoma longifolia (250 ind./㎡) and Magelona japonica (170 ind./㎡), and bivalve Adontorhina subquadrata (73 ind./㎡). Cluster analysis and non-metric multidimensional scaling (nMDS) analysis based on Bray-Curtis similarity identified 2 major station groups which corresponded to macrobenthic faunal assemblages and their characteristic species. In addition, environmental conditions were significantly different between station groups. Group Ⅰ contained mostly 20 and 50 m deep sites and was associated with sandy mud. Group Ⅰ was characterized by high abundance of S. bombyx, S. longifolia, A. subquadrata. It was divided into two sub-groups (Ⅰ-Ⅰ and Ⅰ-Ⅱ) in relation to depth. Sub-group Ⅰ-Ⅰ was associated with deeper sites than sub-group Ⅰ-Ⅱ. Group Ⅱ included mostly inshore area shallower than 15 m and was associated with coarse and medium sand. Group Ⅱ was characterized by Lumbrinerides hayashii and Urothoe grimaldii japonica.