• 한국패류학회지
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• 제28권2호
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• pp.175-185
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• 2012

북한강에 서식하고 있는 참다슬기의 산란생태를 파악하기 위하여 생식소 발달단계에 따른 생식주기, 성비, 군성숙도, 보육낭유생의 월별변화 등 번식생태와 관련된 생물학적 기초 자료를 조사하였다. 각고에 대한 각경, 전중, 육중의 상관계수 ($R^2$) 는 0.7761-0.8719로 비교적 높은 상관관계를 나타내었다. 참다슬기의 암컷 생식소는 청록색, 수컷 생식소는 옅은 황색을 띠고, 암컷은 유생을 기르는 보육낭 (brood pouch) 을 가지고 있었다. 암수성비는 0.17-0.58의 범위로 계절적 불균형이 심하였으며, 여름철 암컷 비율이 높고 겨울철 암컷비율이 낮았다. 생식소의 조직학적 조사 및 비만지수, 생식소지수 조사 결과 봄, 가을에 두 번의 정점을 나타낸 후 급격히 떨어지는 경향을 보여 생식소 발달은 봄, 가을 연 2회 이루어짐을 알 수 있으며, 암컷 보육낭속의 유생수 월별변화도 연중 두 번의 피크를 나타냈었고, 보육낭속의 유생수는 월 평균 286-975범위로, 11월에 연중 가장 적었고 3월과 9월에 각각 975개, 863개로 연중 가장 많은 유생을 보유하였다. 50%가 성숙하는 군성숙체장은 각고 13.95 mm였으며, 각고 15mm 이상은 모든 개체가 성숙하고 보육낭을 형성하였다.

• Animal Systematics, Evolution and Diversity
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• 제25권3호
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• pp.255-259
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• 2009

The sessile ctenophores, Lyrocteis imperatoris Komai, 1941 were collected for the first time from Garinyeo, offshore Seogwipo of Jejudo Island by SCUBA diving on June 18, 2009. This species distributed in West North Pacific was newly recorded in Korean waters. Its embryos in various developmental stages were observed in the internal brood chamber.

• 한국수산과학회지
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• 제15권4호
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• pp.329-332
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• 1982

부산수산대학 양어장에서 1978년부터 1931년 사이에 이스라엘잉어의 산난에 관한 일련의 시도연구를 하였다. 1. 처음 3년간인 1980년 초기까지 노하직체와 상품 Gonadotropin 호르몬 주사에 의한 산난유발을 시도했으나 거의 모두 실패하고, 1980년과 1981년에는 수온상승법에 의한 산난유발을 해본 결과 거의 완벽한 결과를 얻었다. 2. 친어지의 수온은 약 $7\;m^2$되는 소형운형지에 낮은 수온의 샘물을 연속 주입시켜서 $16.9\sim20.2^{\circ}C$의범위로 유지하였으며, 산난지의 수온은 친어지 수온보다 항상 $3.0\sim6.5^{\circ}C$ 높게 준비되었다. 3. 다양의 잉어 뇌하수체나 Gonadotropin을 주사하드라도 수온조절이 되지 않은 상태에서는 이스라엘잉어의 산난이 어렵다는 것을 알았다.

• 한국양식학회지
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• 제20권3호
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• pp.194-198
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• 2007

Reproductive traits of Palaemon gravieri such as embryo size, number of embryo (fecundity), incubation period, larval development mode, larval development period, larval survival and larval growth were described and compared to analyze the correlation among those traits. Embryo volume is a primary factor determining other ensuing reproductive features. Egg volume was $0.042mm^3$ in the first developmental stage. Embryo volume in P. gravieri was comparatively small which is indicative of great number of embryo (y = 3.0161x + 0.0185 $R^2$ = 0.74 positive isometric relationship) and relatively long incubation period. Larvae survived from zoea 1 to post-larvae and it took 45 days at $22^{\circ}C$. Survival rate of the larvae was rather great in the early stage and thereafter steadily decreased. Daily growth rate of larvae in P. gravieri at $22^{\circ}C$ was 0.0195 mm on average. They grew steadily as time went by. Incubation period was between 10-14 days at $22^{\circ}C$. Larval development mode was almost complete planktotrophic. PNR (point of no return) appeared to be the third day on average. Survival rate of larvae without feeding declined rapidly between 3 and 4 days. Larval development period and stage frequency were 23-30 days and 11 stages which imply prolonged larval period and high mortality. The pattern of brood production followed fast successive parturial pattern. Most ovigerous female had mature ovary when they performed parturial molt soon after hatching (larval release).

• Journal of Ecology and Environment
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• 제32권1호
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• pp.33-39
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• 2009

Brood caring behavior was observed in Amaurobius ferox (Araneae, Amaurobiidae), a semelparous subsocial spider, from cocoon construction until the emergence of spiderlings from the cocoon. Unlike most spiders, which emerge from cocoon by their own means, A. ferox mothers intervene in the process of the emergence of their young. I manipulated broods by removing the mother prior to emergence to determine the effects of maternal behavior on the emergence of spiderlings. My results showed that maternal intervention making the cocoon expansion and its exit, is not absolutely necessary for the emergence of A. ferox spiderlings from the cocoon. Nine clutches out of ten were able to get out of the cocoon by their own means without their mother's help. There was no difference between control groups ('with mother') and experimental groups ('without mother') in the number of spiderlings that emerged ($96.9{\pm}25.3$ vs. $90.4{\pm}14.2$, respectfully) and in the time from the beginning to the end of emergence ($36{\pm}12$ vs. $41{\pm}17$ hours). Time from eclosion until the emergence of the first individual in a clutch, however, was greater in the mother-absent group (3.5 days) than in the control group (2.0 days). The construction of the cocoon by the mother required always occurred in the same area within the retreat, and took approximately 6 hours, and the mother guarded the eggs during the incubation period. The emergence of the spiderlings followed a sigmoidal pattern. After emergence, the spiderlings formed a very compact group on the cocoon, which may be important in securing maternal care. The absence of cribellum and calamistrum, structures likely involved in their survival, observed in individuals of the first instar suggests that in the first stage of life, the spiderlings are dependent on their mother.

• 한국환경생태학회지
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• 제21권1호
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• pp.93-100
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• 2007

2004년 2월부터 2005년 6월까지 제주특별자치도 애월읍 신엄리에서 흑로의 번식과정을 조사하였다. 한배 산란수는 $3.24{\pm}0.75$개(N=17, 범위 $2{\sim}4$개)였으며, 알은 새벽이나 밤에 $1{\sim}3$일 간격으로 산란하였다. 알(N=39)의 크기는 장경 $46.73{\pm}l.91mm$, 단경 $34.06{\pm}0.83mm$, 무게 $27.67{\pm}3.12g$, 두께 $0.26{\pm}0.03mm$였다. 흑로의 둥지 보수나 짓기는 매년 2월부터 시작해서 늦게는 4월말까지, 산란기는3월초부터 늦게는 5월 초순까지였고, 부화기는4월 초순에서 5월 중순까지, 이소기는 5월 중순부터 7월말까지였다. 보충 산란은 1차 번식과정 중 포란과 육추에 실패한 $5{\sim}6$월에 바로 시도하는 것으로 추정된다. 포란 기간은 $28.17{\pm}4.12$일(N=6)이었으며, 알은 비동시성으로 부화되었다. 육추 기간은 $40.00{\pm}6.84$일(N=5)이었으며, 새끼의 부리, 날개, 부척, 체중의 성장속도는 부화가 빠른 개체일수록 빠른 경향을 보였다. 우리나라에서 번식하는 백로과 조류의 산란시기를 비교해보면, 흑로는 왜가리보다는 느렸으나, 해오라기, 쇠백로, 중대백로는 보다는 빨랐다.

• 한국어류학회지
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• 제19권4호
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• pp.360-364
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• 2007

큰가시고기목, Solenostomidae (국명신칭: 유령실고기과)에 속하는 Solenostomus cyanopterus 암컷 1개체(표준체장 73.6 mm)가 경북 영덕연안의 수중에서 처음 채집되었다. 다른 실고기류와는 달리, 유령실고기류는 암컷의 배지느러미가 융합되어 변형된 육아낭을 가지고 등지느러미에 극조를 가지는 특징이 있다. 본종은 주둥이의 폭이 넓고 꼬리자루가 짧고 폭이 넓으며, 피질돌기와 줄무늬가 없는 것이 특징이다. 또한 수중에서 관찰한 바로는, 암수 짝을 지어 머리를 아래로 하여 마치 떠다니는 해조류나 낙엽같이 느리게 유영하였다. 본종의 신한국명을 "유령실고기"라고 명명하였다.

• 한국환경보건학회지
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• 제33권2호
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• pp.123-131
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• 2007

Many environmental contaminants including several metals, polycyclic aromatic hydrocarbons, and pharmaceuticals, have been identified to be phototoxic in the water environment. Concerns regarding photo-enhancement of toxicity of several environmental contaminants have been increasing because of the increased level of ultraviolet irradiation on the earth surface. However, there exist arguments that there might be certain defense mechanisms taking place in the aquatic ecosystem, which may include behavioral characteristics or genetic acclimation. This study was conducted to understand the potential responses of aquatic receptors to several phototoxic metals in the real environment, where long-term acclimation of such organisms to low dose UV-B may take place. For this purpose, water flea Daphnia magna was acclimated to environmentally relevant dose of UV-B (12 to $18uW/cm^2$) for >11 generations. The differences in developmental and life history characteristics, and toxicity responses were evaluated. Acclimation did not affect the daphnids' growth, longevity, and reproduction characteristics such as time to first brood, and brood size: After 21 d, survival of D. magna was not influenced by UV-B acclimation. When the number of young per female was compared. the daphnids acclimated for 11 generations tend to produce less number of neonates than the un-acclimated individuals but with no statistical significance (p>0.05). Four metals that were reported to be phototoxic elsewhere were employed in this evaluation, that include As, Cd. Cu, and Ni. UV-B level being applied in acclimation did increase the toxicity of Cd and Cu, significantly (p<0.05). However, the toxicities of As and Ni were not affected by irradiation of UV-B. Phototoxic responses were evaluated between the acclimated and the un-acclimated daphnids. For Cu, UV-B acclimation led to reduction of the photo-induced toxicity $(p\approx0.1)$ in daphnids. Non-acclimated Daphnia were affected by 50% at 4.18 ug/l Cu. but UV-B acclimated individuals exhibited $EC_{50}$ of 5.89 ug/l. With Cd, UV-B acclimation appeared to increase phototoxicity (p>0.05). With As and Ni, UV-B acclimation did not influence photo-induced toxicity. This observation may be in part explained by the type of reactive oxygen species that were generated by each metal. Similar to UV-B light, Cu is known to generate superoxide anion by acting as redox cycling toxicant. This is one of the first studies that employed_laboratory based UV-B acclimated test species for photoenhanced toxicity evaluation.

• 생명과학회지
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• 제9권5호
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• pp.518-524
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• 1999

Timing of oviposition, nuclear maturation of oocytes, egg-sperm contact and brooding were observed in the giant fresh-water prawn Macrobrachium rosenbergii reared in the laboratory. When a pre-spawning molted female was transferred to the male, the female oviposited commonly at 5 to 10 hr after mating. The first polar body were extruded within 2-3 min after spawning. The egg chromosome progressed to release second polar body by 30 min and mitotic nuclear division occurred in 8 hr after spawning. Thumbtack-shaped spermatozoa were seen peneterating egg membrane with their spike directed forward. Transformation of spermatozoa and fertilization membrane could not be observed by light microscopy. The elapsed hours from oviposition to the end of brooding wee taken in 5-7 hr. Brood size for female 9 cm and 18 cm in body length was estimated to be 10,000~15,000 and 100,000 eggs, respectively and is proportional to the total length of the berried females. The ovigerous females reared at chlorinity of 2.21~4.25$\textperthousand$Cl. showed a normal egg development up to hatching.

• Animal cells and systems
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• 제15권1호
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• pp.85-90
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• 2011

In 2001, we conducted a study to assess the effects of differential arrival times and nest-site selection on reproductive performance in a mixed-species heronry consisting of six species in Taeseong-ri, Chungbuk, Korea. We recorded the arrival dates, nest heights, clutch sizes, and brood sizes after 15-20 days of the age of the birds' chicks. The grey herons and cattle egrets arrived first and last, respectively, on the colony site. In the homogenous vegetation structure of the breeding site, the pitch pine trees (Pinus rigida) were mainly used for building nests on 48 of the 50 pine trees (96%). The breeding species vertically stratifies the nest sites according to their body size, except for the cattle egrets and black-crowned night herons that nested at sites higher than those predicted from their body size. The mean nest success rates of the six species under study were positively correlated with the mean nest heights. Our findings suggest that aggressive interspecific interactions among neighbors influence nest-site selection to enhance breeding success.