Change in Morphological and Biological Characteristics by Maturation of Japanese Eel, Anguilla japonica, Collected in Korea Waters

국내에 서식하는 뱀장어 Anguilla japonica의 성숙에 따른 형태 및 생물학적 특성 변화

  • Hong, Yang-Ki (Inland Fisheries Research Institute, National Institute of Fisheries Science) ;
  • Song, Mi-Young (Inland Fisheries Research Institute, National Institute of Fisheries Science) ;
  • Yi, Seok-Eun (CheongShim International Academy) ;
  • Lee, Wan-Ok (Inland Fisheries Research Institute, National Institute of Fisheries Science)
  • 홍양기 (국립수산과학원 중앙내수면연구소) ;
  • 송미영 (국립수산과학원 중앙내수면연구소) ;
  • 이석은 (청심국제고등학교) ;
  • 이완옥 (국립수산과학원 중앙내수면연구소)
  • Received : 2015.10.26
  • Accepted : 2015.12.21
  • Published : 2015.12.31

Abstract

Change in morphological and biological characteristics of Japanese eel, Anguilla japonica, by maturation were determined by examination of 182 individuals collected in Korea waters from September to December 2014. Eels were classified into four stages based on the silvering index. The proportion of silver eels collected from streams and estuaries (34.6%) was higher than that from the freshwater reservoirs (3.8%). The sex ratio between female and male was 1:0.11 (n=182). Mean total length and weight were positively related to the silvering process. The ratios of head and pectoral lengths to total length and the ratio of horizontal and vertical orbital diameters to head length were significantly different between the maturation stages. However the ratio of pre-dorsal and pre-anal lengths to total length were not significantly different between the maturation stages. The gonado-somatic index was the single character that could identify the whole four stages among the indices examined: gonado-somatic index (GSI), condition factor (K), gut index (GI) and eye index (EI) but hepato-somatic index (HSI). One pseudo-silver eel collected. looked like a late silver eel in the S2 stage according to its external body color and morphology, but most of other characteristics suggested that it might be in Y1 (yellow eel) or Y2 stage (late yellow eel).

2014년 9월부터 12월까지 국내에 서식하는 뱀장어 Anguilla japonica 총 182개체를 silvering index에 따라 4개의 단계로 구분하고, 성숙에 따른 형태 및 생물학적 특성 변화를 조사하였다. 하천 및 하구에서 채집한 개체군 (34.6%)은 댐 호 (3.8%)에서 채집한 개체군에 비하여 성숙뱀장어의 비율이 높았다. 성비 (♂/♀)는 0.11 (n=182)로 암컷의 비율이 매우 높았다. 성숙뱀장어 단계로 진행될수록 전장은 커지고, 체중은 증가하였다. 단계별 계측형질 비교에서 전장에 대한 두장 및 가슴지느러미 길이 백분비, 두장에 대한 가로 및 세로 안경의 백분비에서 각각 통계적으로 차이를 보였으나, 전장에 대한 등지느러미 및 뒷지느러미 기점거리에서는 통계적으로 차이를 보이지 않았다. 생식소성숙도지수 (Gonado-somatic index, GSI), 비만도지수 (Condition factor, K), 소화관지수 (Gut index, GI), 안경지수 (Eye index, EI) 및 간 중량지수 (Hepato-somatic index, HSI) 중 GSI는 4가지 단계를 모두 구분할 수 있는 형질이었다. 한편 외부 체색 및 형태는 성숙한 A. japonica인 S2로 보이지만, 나머지 대부분의 단계별 분류 형질에서는 미성숙뱀장어인 Y1과 Y2에 해당하는 pseudo-silver eel 한 개체가 채집되어 이에 대한 형질을 비교하였다.

Keywords

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