Reproductive cycle with the gonadal phases, first sexual maturity, artificial spawning amount by the size and spawning interval of the hard clam, Meretrix lusoria were investigated by histological observations and morphometric data by artificial spawning induction. Meretrix lusoria is dioecious and oviparous. The reproductive cycle of this species can be classified into five successive stages: early active stage (January to March), late active stage (February to May), ripe stage (April to August), partially spawned stage (June to September), and spent/inactive stage (September to February). The spawning period was from June to September, and the main spawning occurred between July and August when the seawater temperature exceeds over <TEX>$20^{\circ}C$</TEX>. Percentage of first sexual maturity of female and male clams ranging from 40.0 to 45.0 mm in shell length was over 50%, and all clams over 50.0 mm in shell length sexually matured. Female and male clams ranging from 40.0 to 45.0 mm in shell length are considered to be two years old. Therefore, we assume that the hard clams of both sexes begin reproduction from two years of age. The mean number of the spawned eggs increased with the increase of size (shell length) classes. In case of artificial spawning induction, the number of spawned eggs from the clams of a sized class was gradually decreased with the increase of the number of the spawning frequencies (the first, second, and third spawnings). In the experiments of artificial spawning induction during the spawning season, the interval of each spawning was estimated to be 15-18 days (average 17 days).
Gonadosomatic index, reproductive cycle, spermatogenesis and first sexual maturity of Chlamys farreri were investigated by cytological and histological observations, from January 1998 to December 1999. The gonadosomatic index (GSI) rapidly increased in April and reached a maximum in May when seawater temperature rapidly increase. Then the GSI gradually decreased from June to August when spawning occur. Accordingly, monthly changes in the GSI in males coincide with the reproductive cycle. The spermatozoon of Chlamys farreri is the primitive type found in external fertilization species. The head of the spermatozoon is approximately <TEX>$2.75{\mu}m$</TEX> in length including the acrosome measuring about <TEX>$0.50{\mu}m$</TEX> in length, and its tail was approximately <TEX>$20{\mu}m$</TEX>, the axoneme of the tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. Five spherical mitochondria around the centriole (the satellite body) appear in the middle piece of the sperm. The spawning period was from June to August and the main spawning occurs from July to August when seawater temperatures are greater than <TEX>$20^{\circ}C$</TEX> The reproductive cycle of this species can be categorized into five successive stages; early active stage (January to March), late active stage (March to April), ripe stage (April to August), partially spawned stage (June to August), and spent/inactive stage (August to January). Over 50% of male scallops attained first sexual maturity between 50.0 and 60.0 mm in shell height, and 100% of those over 60.0 mm in shell height achieved maturity. Accordingly, we assume that male individuals begin reproduction at three years of age.
나팔고둥의 효율적인 종묘생산을 위한 생물학적 기초자료를 얻고자 산란유발, 유생 및 치패사육에 미치는 수온의 영향에 대하여 실험한 결과는 다음과 같다.수온별 나팔고둥의 산란양을 조사한 결과, 가장 많은 산란을 한 15℃에서 전체 암컷이 2003년 11월에 113 개의 난낭을 산란하였고, 12월 345 개, 2004년 1월 1,232 개, 2월에 1,045 개의 난낭을 산란하여 우리나라에서 나팔고둥의 산란기는 1월과 2월임을 알 수 있었다.나팔고둥의 발생속도를 파악하기 위한 난발생과 유생의 성장 단계는 수정란, 4-세포기, 8-세포기, 상실기, trochophore, veliger, hatched veliger로 구분하였는데, 난낭을 뚫고 부출하기까지 약 50-83일이 소요되었다. 각 발생 단계의 수온별 소요시간을 보면 8-세포기까지 10℃에서는 10일, 15℃에서 7일이 걸렸고, 20℃와 25℃에서는 5일이 소요된 반면, 5℃와 30℃에서는 발생이 관찰되지 않았다.나팔고둥 유생의 수온별 성장을 조사한 결과, 10℃와 30℃에서는 모든 유생이 폐사하였고, 25℃의 경우 실험개시시 평균체장 408 ± 21.52 m이던 유생의 30일 경과 후 544 ± 23.22 m, 60일 경과 후 683 ± 19.76 m로 성장하여 가장 높은 성장을 보였으나, 생존율은 10%로 가장 낮았다. 또한 15℃의 경우 30일 경과 후 509 ± 18.34 m, 60일 후 625 ± 19.76 m로 성장하였고, 생존율은 23%로 가장 높게 나타나 치패사육시 가장 적정한 수온은 15℃라 판단되었다.
In the present study, the fecundation and fertilization behaviors of the trumpet shell, Charonia lampas sauliae were observed from November 2003 to March 2004.Female has multiple fecundation and multiple fertilization, and the fertilization continued for two days.The fertilized female stayed with the egg mass to protect the eggs, and the fecundation was made during the fertilization.The highest survival rate of egg capsule was 60% at 15℃.Charonia lampas sauliae fed with Chaetoceros calcitrans, Isochrysis galbana, and Pavlova lutheri. Growth and survival rates of C. lampas sauliae in the conditions of various water temperature were observed. The highest survival rate was 23% at 15℃ reared for 60 days. The growth was presented in the 15℃ group, with shell length from 408 ± 21.52 m to 625 ± 19.76 m during the experiment.
1995년 10월부터 1997년 10월까지 2년간 제주도 서귀포시 법환 어장 및 전라남도 장흥군 득량만 어장에서 키조개 자연채묘와 치패의 성장을 조사하였다.환경조사에서는 수온은 법환 어장 14.1-24.1℃, 득량만 어장 4.7-28.5℃로서 법환 어장의 최저수온이 득량만 어장에 비해 9.4℃ 높았으며, 최고 수온은 4.4℃ 낮게 나타났다. 그 외의 8개 항목의 수질은 비슷한 결과를 나타내었으나 용존 무기질소가 법환 어장에서 다소 낮게 나타났으며 키조개의 서식에는 큰 영향을 미치지 않는 범위였다.자연채묘는 키조개의 채묘기당 부착밀도는 법환 어장의 경우 10-13 m 수층에서 6.6 개체로 가장 높게 나타났고 득량만 어장에서는 1.9 개체였다. 월별로는 8월에 채묘를 실시한 시험구가 부착밀도 및 성장이 가장 좋았다. 부착한 키조개 치패의 성장은 채묘 6개월 후 평균 각장 42.5 mm로 성장하였으며, 부착일수에 따른 각장의 관계식은 Y = 0.3854X ＋ 0.8423 (r2 = 0.9764) 로 나타낼 수 있었다. 수심별 부착밀도 및 성장은 10-21 m층이 표층 및 저층에 비해 좋았다.키조개 치패의 망목크기는 1 × 2 mm가 가장 좋았고, 부착기질은 polyethylene monofilament가 가장 양호한 것으로 조사되었다.
In this experiment of natural Atrina pectinata spat collection, the number of the pen shell spats settled on a collector was 4.2, 6.8, and 2.7 in the first, second, and third year, respectively. The highest number of pen shell spat settled on the collector was observed in August, and the shell length of juvenile pen shells grew up to 42.5 mm six months after setting. The relation between shell length and days after setting could be expressed as; shell length = 0.3854 x days after setting ＋ 0.8423 (r2 = 0.9764). The spats developed the best in depth of 10-20 m. Spat collectors in mesh size of 1 x 2 mm were better for spats to survive than the ones in 1 x 1 mm. The most efficient material as substrate for the settlement of pen shell spat was a polyethylene monofilament in the spat collectors.
2004년 1월부터 12월까지 가리맛조개, Sinonovacula constricta의 생식소 발달단계에 따른 생식주기를 조직학적 관찰에 의해 조사하였고, 폐각근과 내장낭, 족부근육 및 외투막의 생화학적 성분의 계절적 변화를 생화학적 분석방법에 의해 조사하였다. 본 종의 생식주기는 초기활성기 (3-5월), 후기활성기 (5-7월), 완숙기 (7-9월), 부분산란기(8-10월), 퇴화 및 비활성기 (10-3월) 의 연속적인 5 단계로 구분할 수 있었다. 총단백질 함량은 폐각근, 내장낭, 족부근육, 외투막 중 폐각근에서 가장 높았다. 외투막을 제외하고 일반적으로 성숙 및 산란기 중에 좀 더 높았다. 그러나 비활성기 중에는 좀 더 낮았다. 폐각근, 족부근육 및 내장낭 사이의 총단백질 함량은 양(+)의 상관관계를 나타내었다. 그러나 상관성은 통계학적으로 유의하지 않았다. 총지질 함량은 내장낭 내에서 가장 높았는데 폐각근, 족부근육 또는 외투막 내의 함량 보다 5-6배 더 높았다. 월별 변화는 내장낭 내에서 가장 크게 나타났는데, 초기활성기 (3-5월) 중에 처음 증가한 후 후기활성 기 (5-7월) 에 감소하였다. 그리고 산란기 (9월) 중에 급격하게 다시 증가했다. 족부근육파 폐각근 사이의 총지질 함량간에는 강한 음 (-)의 상관관계 (r = -0.634, p = 0.027)를 보였고, 폐각근과 외투막 사이에는 강한 양 (+) 의 상관관계 (r = 0.665, p = 0.018)를 나타내었다. 글리코겐 함량은 폐각근, 족부근육 그리고 내장낭 내의 총지질 함량 변화와 다소 유사한 경향을 보였다. 함량 변화는 초기활성기와 산란기 중에 높았고, 후기활성기와 퇴화 및 비팔성기 중에는 낮게 나타났다. 각 조직들 사이에 글리코겐 함량의 상관성은 통계학적으로 유의하지 않았다. 특히, 총지질 함량은 족부근육, 폐각근, 내장낭 및 외투막 사이에 음 (-) 의 상관관계를 나타내었다. 그러므로 이들 결과는 족부근육, 폐각근, 내장낭 및 외투막의 영양성분이 생식소의 에너지 요구에 반응하여 변하는 것으로 추정된다.
We investigated the reproductive cycle with gonad developmental phases of Sinonovacula constricta by histological observations, and seasonal changes in biochemical component of the adductor muscle, visceral mass, foot muscle and mantle were studied by biochemical analysis, from January to December, 2004. The reproductive cycle of this species can be classifed into five successive stages: early active stage (March to May), late active stage (May to July), ripe stage (July to September), partially spawned stage (August to October) and spentfinactive stage (October to March). Total protein content was the highest in the following order: adductor muscle, visceral mass, foot muscle, and mantle. Except for mantle, it was generally higher during the ripe and spawning stages, while lower during the spent/inactive stage. There were positive correlations in total protein contents among adductor muscle, foot muscle, and visceral mass. However, the correlations were not statistically significant. Total lipid content was the highest in the visceral mass; it was more than 5 or 6-fold higher than those in the adductor muscle, foot muscle, or mantle. The monthly change was also most dynamic in the visceral mass. It first Increased during the early active stage (March to May), decreased during late active stage (May to July), and then increased again rapidly during the spawning stage (September). There were a strong negative correlation in total lipid contents between foot muscle and adductor muscle (r = -0.634, p = 0.027), and a strong positive correlation between adductor muscle and mantle (r = 0.665, p = 0.018). Glycogen contents showed more or less similar pattern to total lipid contents in the adductor muscle, foot muscle, and visceral mass. It was higher during the early active and spawning stages, while lower during the late active and spent/inactive stages. There was no statistically significant correlation in glycogen contents among different tissues. Especially, total lipid content showed a negative correlationship between the foot muscle, adductor muscle, visceral mass and mantle. Therefore, these results indicate that the nutrient content of the foot muscle, adductor muscle, viseral mass and mantle changed in response to gonadal energy needs.
Eight species of bithyniids, Bithynia leachi, B. tentaculata, B. siamensis, B. misella, B. kiusiuensis, B. striatula, Bithynia sp. from Nepal and Gabbia australis were collected from 1957 to 1988. The samples were relaxed with pentobarbital and fixed with 70% ethyl alcohol. There was no significant difference in internal structure of soft body, except the male reproductive system. The alimentary canal of the bithyniids consisted of mouth, buccal mass, esophagus, stomach, intestine, rectum and anus. The heart consisted of an auricle and a ventricle, located at left side of the stomach in the visceral hump. The ctenidium comprised 40-70 subtriangular lamellae. Eight ganglia were located around upper esophagus. The female reproductive system comprised ovary, oviduct, spermaaheca, and albumin gland. The male reproductive system was composed of testis, seminal vesicle, prostate gland, vas deferens, penial duct, and penis in order. Male was distinguished externally from the female by a bifid penis.
백합 상과의 계통분류학적 유연관계를 알아보기 위하여 14 종의 이치 아강 이매패류와 3 종의 익형 아강 패류를 대상으로 28S rRNA의 일부 염기서열을 분석한 뒤 GenBank에 등록된 관련 종들의 염기서열을 취득하여 PAUP 프로그램을 이용하여 최대 절약분석을 실시한 결과 다음과 같은 결과을 얻었다.분석된 1,480 개의 형질 (gap 포함) 중 560 개의 형질이 parsimony 결과 informative하였다. 하나의 가장 절약적인 분지도를 구했을 경우 전체 분지의 길이는 2765였고 consistency index (CI) = 0.4843, homoplasy index (HI) = 0.5157, Retention index (RI) = 0.6291 로 나타났다.동일 종 표본, Corbicula fluminea와 Sinonovacula constricta의 경우 각각 3.1 %, 1.2%의 차이를 보였다.Pitarinae-Cyclininae-Meretrinae가 하나의 분지를 이루고 있었고, Samaranginae-Chioninae-Dorsininae가 다른 하나의 분지를 이루고 있었다.
To elucidate the phylogenetic relation of the superfamily Veneroidea, we obtained partial 28S rRNA sequences of 14 heterodonts and three pteriomorphs which were collected from Korea and the sequence data of related taxa from GenBank, and analyzed maximum parsimony with PAUP program.750 of the nucleotide positions were variable, 560 of which were informative under conditions of parsimony. Total tree length was 2,765, and consistency index, homoplasy index (HI), and Retention index was 0.4843, 0.5157, and 0.6291, respectively. Intraspecific variation of 28 rRNA of Corbicula fluminea and Sinonovacula constricta was 3.1% and 1.3%, respectively. Pitarinae-Cyclininae-Meretrinae group had a clade and Samaranginae, Chioninae, and Dorsininae were clustered.
