全頭類の研究-2 : 長崎県沿岸域で捕獲されたギンザメChimaera phantasma JORDAN et SNYDERの生殖について

The internal sexual organs and reproduction of Chimaera phantasma caught in the coastal waters of Nagasaki were investigated. The testes of C. phantasma is that of seminiferous follicle type. The seminiferous follicles develop more in the region near the outer pole of the testis. Both ovaries are functional and each gonopores open separately without the cloaca. Some ova were covered in the capsule one by one at the nidamental gland, as in most Elasmobranchii, and the ova were spawned in succession in the same breeding season. Sexual maturity in females was apparently reached at a body length of about 63cm, while in males it was attained at about 51cm. The reproductive season of C. phantasma appears to last about a half year, with the peak activity during winter.1975年から1980年まで長崎沿岸域より採集された408個体(雄・164,雌・244)のギンザメChimaera phantasmaの生殖器官の調査を行った.本種の生殖腺の発達過程は板鰓類のそれとは全く異なるが,生殖器官の形態・様式及び精子形式の過程等は極めてよく似ている.そこで,ギンザメの生殖について板鰓類と比較しながら述べた.本種の生殖腺は多くの板鰓類と異なり,雌雄とも又左右いずれも機能的である.雄は体長約51cm,雌は約63cmで性的成熟体長に達すると考えられる.産卵直前の卵は直径40mm以上にもなり,連続していくつかの卵をカプセルにつつんで産出する.産卵期は冬期を中心にして半年近くの長期にわたるものと考えられる

全頭類の研究-1 : ギンザメChimaera phantasmaの形態と雄の生殖器官について

The morphological characters and ecology of Chimaera phantasma and male\u27s reproductive organs were investigated. Specimens (115 males, 191 females) were collected at the Nagasaki Fish Market or caught by the authors themselves from September 1975 to October 1976. The variation of proportion percentages compared with body length is not remarkable and the growth curves of the male and female are indicated by the following formula: Male: W=0.1913L2.2269 Female:W=0.0376L2.6349 It was observed that the male\u27s condition factor increases with the increment of body length, but no seasonal variation of this factor could be observed. In females no variations of any kind were observed. The diet is basically formed by Crustacea, especially crabs, and teeth consist of three pairs of dental plates. The posterior clasper is trifurcated and has no remarkable appendices. External radii are rigid and the anterior clasper bears 8 serrations in a line. The pelvic girdle consists of right and left cartilages. Sexual maturity in males can be considered to be reached at a body length of 45 to 50cm.1975年9月から1976年10月にかけて長崎魚市に水揚げされたり,著者らが長崎県沿岸で採捕したギンザメ306個体(雄115個体,雌191個体)について,形態学的に,雄についはは生殖生態についても調査した。成長に伴う各部の外形プロポーションの割合はほぼ一様である。また,雌雄の成長式は次式で示された。雄:W(g)=0.1913L(cm)2.2269 雌:W(g)=0.0376L(cm)2.6349雄の肥満度は成長に伴い減少するのが観察された。歯は非常に強固な三対の歯板よりなり,主として底棲動物を捕食し,中でも小型のカニを最も多く捕食している。Posterior clasperは三叉し,先端は顕著な附属物はなく,external radiiは屈曲しない。Anterior clasperの内縁には一列に並んだ8個の棘があり,Pelvie girdleは左右二つに分離している。本種の雄は体長(No. 14) 45cmから50cmで成熟に達する

ギンザメChimaera phantasmaの精子形成について

Comparing with the fine structure of spermatogenic cell of selachians and oter vertebrates, that of the chimaera was observed with light and electron microscopes. The origin of chimaera testis differed essentially from that of selachians. However the chimaera had many resemblances to the selachians in the formation of the spermatozoon, except for the following two points; first, the X organ and the axial midpiece rod of the neck were amorphous and, second, there was only one accessory on the tail flagellum.ギンザメの精細胞の微細構造について,板鰓類並びに他の脊椎動物のそれと比較しながら,電子顕微鏡的観察を行った.精巣の起源は板鰓類のそれとは全く異なる.精子の形態は次の二点を除いて板鰓類とは多くの類似点を有する.すなわち,その相違点とは,頸部のXorganとaxial midpiece rodのいずれもが無構造であること,および尾部のアクセサリーが一つしかないことである

全頭類の研究-1 : ギンザメChimaera phantasmaの形態と雄の生殖器官について

The morphological characters and ecology of Chimaera phantasma and male's reproductive organs were investigated. Specimens (115 males, 191 females) were collected at the Nagasaki Fish Market or caught by the authors themselves from September 1975 to October 1976. The variation of proportion percentages compared with body length is not remarkable and the growth curves of the male and female are indicated by the following formula: Male: W=0.1913L2.2269 Female:W=0.0376L2.6349 It was observed that the male's condition factor increases with the increment of body length, but no seasonal variation of this factor could be observed. In females no variations of any kind were observed. The diet is basically formed by Crustacea, especially crabs, and teeth consist of three pairs of dental plates. The posterior clasper is trifurcated and has no remarkable appendices. External radii are rigid and the anterior clasper bears 8 serrations in a line. The pelvic girdle consists of right and left cartilages. Sexual maturity in males can be considered to be reached at a body length of 45 to 50cm.1975年9月から1976年10月にかけて長崎魚市に水揚げされたり,著者らが長崎県沿岸で採捕したギンザメ306個体(雄115個体,雌191個体)について,形態学的に,雄についはは生殖生態についても調査した。成長に伴う各部の外形プロポーションの割合はほぼ一様である。また,雌雄の成長式は次式で示された。雄:W(g)=0.1913L(cm)2.2269 雌:W(g)=0.0376L(cm)2.6349雄の肥満度は成長に伴い減少するのが観察された。歯は非常に強固な三対の歯板よりなり,主として底棲動物を捕食し,中でも小型のカニを最も多く捕食している。Posterior clasperは三叉し,先端は顕著な附属物はなく,external radiiは屈曲しない。Anterior clasperの内縁には一列に並んだ8個の棘があり,Pelvie girdleは左右二つに分離している。本種の雄は体長(No. 14) 45cmから50cmで成熟に達する

Status of live feed culture for aquaculture purpose in Mexico

Scant information is available in Mexico about institutes involved in live food culture. An inquiry was carried out in order to assess the status of microalgae and zooplankton culture in Mexico. The use of live food in Mexico is basic for aquaculture commercial activities. Twelve research or educational institutes maintain stock collection and offer them to growers and individuals. Half of the inquired institutions cultured microalgae and zooplankton for commercial activities, the other half focuses their attention mainly to research. The Guillard f/2 medium is most commonly used. and transparent fiber glass containers are most frequently employed. The highest production of microalgae is 1400,000 liters per day and the average surface of production was 36 m2 with three people working on it