Occurrence and Survival Rate of the Larvae of Ark Shell Anadara broughtonii in Chinhae Bay

진해만(鎭海灣)에서의 피조개 Anadara broughtonii 부유유생(浮游幼生)의 출현(出現)과 생존율(生存率)

In order to set up a predictive model for an effective spat collection of ark shells, Anadara broughtonii, the survival rate and the time required for each developmental stage of planktonic larvae were investigated during the period from July 1 to October 30 in 1974, in one of the main ark shell seed collection areas, Chinhae Bay, in the southern part of Korea. The advent of D-shaped larvae ca. $94.3{\times}72.7{\mu}m$ long had three peaks during the surveyed period: August 25, August 31 and September 9, umbo-shaped larvae ca. $141.6{\times}108.4{\mu}m$ and full grown larvae ca. $269.3{\times}221.7{\mu}m$ long also showed three peaks: September 6, September 12 and September 20 for the former, and September 20, September 25 and October 5 for the latter, respectively. About 11 to 12 days was required for D-shaped larvae to develop to umbo-shaped stage. At this intermorphological stage, the daily survival rate was 0.93 with a total survival rate of 45% for the stage. The time required for umbo-shaped larvae to develop to full grown larvae varied from 13 to 15 days with a daily survival rate of 0.93 and with a total survival rate of 36% in the period. Twenty-five to twenty-six days were required for each peak group of the D-shaped larvae to reach a full grown stage, and their total survival rate was 16% during this developmental stage.

피조개(Anadara broughtonii)의 효율적(效率的)인 종묘생산기술개발(種苗生産技術開發)을 목적(目的)으로 1974년(年) 7월(月)부터 10월(月)까지 진해만내(鎭海灣內)의 가조도 앞바다에서 부유유생(浮游幼生)의 출현시기(出現時期)와 각(各) 유생단계별(幼生段階別) 생존율(生存率)을 조사(調査)하였다. 조사기간중(調査期間中) 크기가 약(約) $94.3{\times}72.7{\mu}m$인 D형유생(型幼生)은 8월(月) 25일(日), 8월(月) 31일(日) 및 9월(月) 9일(日)에 각각(各各) 가장 많은 개체가 출현(出現)하였으며, $141.6{\times}108.4{\mu}m$인 umbo형유생(型幼生)은 9월(月) 6일(日), 9월(月) 12일(日) 및 9월(月) 20일(日)에, $269.3{\times}221.7{\mu}m$의 성숙유생(成熟幼生)은 9월(月) 20일(日), 9월(月) 25일(日) 및 10월(月) 5일(日)에 각각(各各) 출현개체수(出現個體數)가 가장 많았다. D형유생(型幼生)에서 umbo형유생(型幼生)으로 되는데는 약(約) 11~12일(日) 걸렸으며, 일간생존율(日間生存率)은 0.93, 생존개체수(生存個體數)의 백분비(百分比)는 45%였다. umbo형유생(型幼生)에서 성숙유생(成熟幼生)으로 되는데는 약(約) l3~15일 걸렸으며 일간생존율(日間生存率)은 0.93, 생존개체수(生存個體數)의 백분비(百分比)는 36%였다. D형유생(型幼生)의 발생(發生)에서 채묘(採苗)의 대상(對象)이 되는 성숙유생(成熟幼生)으로 되는데는 25~26일(日)이 걸렸으며 이 기간중(期間中) 생존개체(生存個體)의 백분비(百分比)는 16%였다.