Studies on Reproduction and Age Determination of Deep-sea Squalidae, Deania spp.
Grant-in-Aid for Scientific Research (C)
|Research Institution||Tokai University|
TANAKA Sho Tokai University, School of Marine Science & Technology, Professor, 海洋学部, 教授 (90138636)
|Project Fiscal Year
1996 – 1997
Completed(Fiscal Year 1997)
|Budget Amount *help
¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1997 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1996 : ¥600,000 (Direct Cost : ¥600,000)
|Keywords||Squalidae / Deania / Reproduction / Embryonic nutrition / Maturity / Age estimation / Spine / Growth ring / サガミザメ / ヘラツノザメ / 生殖器官 / 組織学的観察 / 生化学的分析 / 栄養吸収 / 背鰭棘 / 年齢成長 / 胎仔 / 乾燥重量 / 年齢形質 / 成熟|
1.Male performed spermatogenesis through the year.
2.Males of both species did not have a clear reproductive cycle and copulative season.
3.Female carried 6 to 24 embryos in her uteri. Females collected in the same month had various size of embryos, so females also have no distinct copulative, ovulatory and delivery seasons.
4.Minimum mature size of male and female Deania calcea was 650 mm TL and 822 mm TL,respectively, and in male and female D.hystricosa was 750 mm and 1020 mm, respectively.
5.Water content in wet weight of fertilized eggs (FE) ranged from 50 to 55%, while that in the embryos increased lineally to 70 % with their growth.
6.Dry weight of the embryos with external yolk sac smaller than 100 mm TL was almost equal to that of FE,but the embryos larger than 100 mm tended to be light with their growth.
7.Dry weight of the liver in the embryos began to increase suddenly after embryos had grown to 105 mm.
8.Protein concentration of maternal blood plasma hardly changed with embryonic
growth, whiie that of uterine fluid decreased ; about 16 mg/ml to FE,7mg/ml to the 75 mm embryo, and less than 2.5 mg/ml to the embryos over 140 mm.
9.Uterine fluid profiles showed proteins of 40-60 kd specifically at the developmental stages from FE to the 105 mm embryo. Proteins of 14-40 kd and 60-79 kd were observed at every stage.
10.Yolk matter was observed ih the intestinal lumen of the embryos over 105 mm.
11.The spines of both species had no growth band on their surface.
12.The spine length in D.calcea increased lineally with body size and their correlation coefficients were high significant. In D,hystricosa, the covariance between body size and spine length was high and their correlation coefficients were low.
13.The spine consisted of five structural components ; mantle, protruding dentine portion, stem, pulp cavity, cartilaginous tissue.
14.Growth rings were observed on the inner dentine layr of stem. The newly growth ring was formed inside the inner dentine layr.
15.The number of growth rings increased lineally with body size. Small D.calcea had one ring.
16.D.calcea and D.hystrlcosa had 1-15 and 6-15 rings, respectively.
17.Mode was 6th ring in male D.calcea, 10th ring in female D.calcea, 9th ring in male D.hystricosa, and13th ring in female D.hystricosa.
18.We could not verify that growth ring is formed annually. Less
Research Output (2results)