Reproductive ecology, spawning, hatching, survival and cannibalism of the octopus, Octopus ocellatus, were investigated at the indoor laboratory. The specimens were collected at the coastal waters of Puan, Chollabuk-do, Korea, from 2000 to May 2001. O. ocellatus is a dioecious organism. The gonad of...
Reproductive ecology, spawning, hatching, survival and cannibalism of the octopus, Octopus ocellatus, were investigated at the indoor laboratory. The specimens were collected at the coastal waters of Puan, Chollabuk-do, Korea, from 2000 to May 2001. O. ocellatus is a dioecious organism. The gonad of O. ocellatus locate medially in posterior region of the body and Its were continuous with pericardial cavity. Morphology of female and male gonad show round and oval in shape in all, the average diameter and external colour of ripe male and female gonad were 17 mm (milky white in colour) and 32 mm (semitransparent light brown in colour), respectively. As the ovary was getting mature, transparent elongated eggs covered with chorion were present in the ovarian cavity. Mean body weight and the size of mantle length were 74.7 g, and 6.0 cm in mature females, and 36.2 g, and 4.2 cm in males. Reproductive cycle of O. ocellatus can be categorized into five successive stages: for females, early developing stage (September to December), late developing stage (November to March), ripe stage (March to May), spawning stage (April to June), and degenerative/resting stage (June to October); for males, early developing stage (September to October), late developing stage (September to December), ripe stage (March to June), copulation stage (March to May), and spent/resting stage (June to September). Spawning occurred between April and June in female, and between March and May in male. This species showed a protandry phenomen on. The spawning period was once a year and the peak took place between May and June. This species belongs to semelparity. The sex ratios of females and males were not significantly different from 1:1 (χ² = 3.760, p>0.05). Follicular cells attached to an oocyte were involved in vitellogenesis in the cytoplasm of the vitellogeneic oocyte and formation of chorion (secondary egg membrane) of the ovarian eggs. Fecundity per female closely related to GSI was 285∼669 eggs (average, 418 eggs, 2000). According to changes in biochemical contents of the ovary and the digestive organ, monthly variations of moisture content (%), total protein content (%), total lipid content (%) and glycogen content (%) in the ovary showed a negative correlationship with those of the digestive organ. Accordingly, it is assumed that the ovary may receive nutrient supply from the digestive organ. When the juvenile octopuses are discharged, it is hard to separate capture because they attached strongly to the wall of the aquarium by the suckers on the arms. Therefore, anesthetic (MS-222 or lidocaine-Hcl) are usually used for capture. The anesthetized time of the octopus by lidocaine-Hcl was more faster 1.6 to 4.5 time under 200 ppm and 6.0 to 6.5 time in 300 to 500 ppm than MS-222. In the anesthetic and recovery rates (%) by the exposed time, the juvenile octopuses were anesthetized by low concentration of lidocaine-Hcl in the short time, and recovered rapidly octopuses from anesthesia. In the secondary anesthesia of the juvenile octopuses exposed with lidocaine-Hcl by the elapsed time after the primary anesthesia, the anesthetized time was later when their concentrations were low and the elapsed times were long, however the anesthetized time was faster when their concentrations were higher and the elapsed time after anesthesia were shorter. Recovery from the secondary anaesthesia was faster when the elapsed time was long in lower concentration, and was later when the elapsed time was shorter. In case of O. ocellatus, effects of anaesthesia by lidocaine-Hcl was better than MS-222. Doses (concentrations used) and critical time for works at the indoor laboratory were proper in concentration of 100 ppm within 15 min.
Reproductive ecology, spawning, hatching, survival and cannibalism of the octopus, Octopus ocellatus, were investigated at the indoor laboratory. The specimens were collected at the coastal waters of Puan, Chollabuk-do, Korea, from 2000 to May 2001. O. ocellatus is a dioecious organism. The gonad of O. ocellatus locate medially in posterior region of the body and Its were continuous with pericardial cavity. Morphology of female and male gonad show round and oval in shape in all, the average diameter and external colour of ripe male and female gonad were 17 mm (milky white in colour) and 32 mm (semitransparent light brown in colour), respectively. As the ovary was getting mature, transparent elongated eggs covered with chorion were present in the ovarian cavity. Mean body weight and the size of mantle length were 74.7 g, and 6.0 cm in mature females, and 36.2 g, and 4.2 cm in males. Reproductive cycle of O. ocellatus can be categorized into five successive stages: for females, early developing stage (September to December), late developing stage (November to March), ripe stage (March to May), spawning stage (April to June), and degenerative/resting stage (June to October); for males, early developing stage (September to October), late developing stage (September to December), ripe stage (March to June), copulation stage (March to May), and spent/resting stage (June to September). Spawning occurred between April and June in female, and between March and May in male. This species showed a protandry phenomen on. The spawning period was once a year and the peak took place between May and June. This species belongs to semelparity. The sex ratios of females and males were not significantly different from 1:1 (χ² = 3.760, p>0.05). Follicular cells attached to an oocyte were involved in vitellogenesis in the cytoplasm of the vitellogeneic oocyte and formation of chorion (secondary egg membrane) of the ovarian eggs. Fecundity per female closely related to GSI was 285∼669 eggs (average, 418 eggs, 2000). According to changes in biochemical contents of the ovary and the digestive organ, monthly variations of moisture content (%), total protein content (%), total lipid content (%) and glycogen content (%) in the ovary showed a negative correlationship with those of the digestive organ. Accordingly, it is assumed that the ovary may receive nutrient supply from the digestive organ. When the juvenile octopuses are discharged, it is hard to separate capture because they attached strongly to the wall of the aquarium by the suckers on the arms. Therefore, anesthetic (MS-222 or lidocaine-Hcl) are usually used for capture. The anesthetized time of the octopus by lidocaine-Hcl was more faster 1.6 to 4.5 time under 200 ppm and 6.0 to 6.5 time in 300 to 500 ppm than MS-222. In the anesthetic and recovery rates (%) by the exposed time, the juvenile octopuses were anesthetized by low concentration of lidocaine-Hcl in the short time, and recovered rapidly octopuses from anesthesia. In the secondary anesthesia of the juvenile octopuses exposed with lidocaine-Hcl by the elapsed time after the primary anesthesia, the anesthetized time was later when their concentrations were low and the elapsed times were long, however the anesthetized time was faster when their concentrations were higher and the elapsed time after anesthesia were shorter. Recovery from the secondary anaesthesia was faster when the elapsed time was long in lower concentration, and was later when the elapsed time was shorter. In case of O. ocellatus, effects of anaesthesia by lidocaine-Hcl was better than MS-222. Doses (concentrations used) and critical time for works at the indoor laboratory were proper in concentration of 100 ppm within 15 min.
주제어
#수산 양식[水産養殖] 한국 서해산 주꾸미 생식생태 종묘생산 REPRODUCTIVE ECOLOGY SEEDLING PRODUCTION OCTOPUS OCELLATUS WEST COAST KOREA
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