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アワビ属の採卵技術に関する研究(5)
誌名誌名 東北区水産研究所研究報告
ISSNISSN 0049402X
巻/号巻/号 34
掲載ページ掲載ページ p. 77-85
発行年月発行年月 1974年12月
農林水産省 農林水産技術会議事務局筑波産学連携支援センターTsukuba Business-Academia Cooperation Support Center, Agriculture, Forestry and Fisheries Research CouncilSecretariat
TECHNICAL STUDY ON ARTIFICIAL SPAWNING OF ABALONE,
GENUS HALIOTIS V. RELATION BETWEEN WATER
TEMPERATURE AND ADVANCING SEXUAL MATURITY
OF HALIOTIS DISCUS REEVE
By
Shδgo KIKUCHI and Nagahisa UKI
As for the northern abalone, H. disc叫shannai INo, it was reported by the authors
that sexual maturity advanced corresponding to the integral water temperature and
that the result o任巴reela basis of technique for artificial seed production throughout
a year. In the present paper, an experiment for advancing the sexual maturity of the
southern abalone, H. discits REEVE, as related with temperature, is dealt with.
The adult abalone were caught on th巴 coastalrocky bottom of Yamagata Prefecture,
facing the Japan Sea, in December, 1972. They were reared in 8°C to 10。cwater
temperature conditions for two months before the experiment was started in our
laboratory. During the period of February through August in 1973, which is out of
the spawning season of this species, the experimental rearing was carried out under
the water temperature of about 14。C,19°C and 22°C, and the control at a half day
period of light-and-dark conditions between 2 :00 P.M. Thirty adults were kept in each
rearing tank. They were fed well with fresh seaweeds of U叫daria,L即時間a門a and
Eis向日 (see Table 1 ). The rearing conditions for the adults seemed to be suitable
from the results of feeding and growth as shown in Table 2. Artificial spawqing was
done by the method of 2,537A U.V. irradiat巴dsea water (KIKUCHI and UKI, 1974b).
The treatments for rearing and the observations of gonad development were as des-
cribed in the previous paper {KIKUCHI and UKI, 1974a). The results are as follows.
1. The sexual maturity indicated by the Gonad Index (abbr. G.I.) increased
reasonably to related the water temperature and the advancement was rapid at the high
water temperature condition as shown in Fig. 2. In the sexual maturity, the increas・
ing of G.I. per day (Y1 ti) is directly proportional to the water temperature (t) as shown
by the followi咋 equation(see Fig. 2):
Y1 t> =0.00102t-0.00548
The equation shows that G.I. advances in proportion to the integral water temperature
{abbr. I.W.T.) of above 5.3°C.
2. On the advancement of sexual maturity of the abalone based on the I.W.T.
it can be summerized from the experiment as follows (see Figs. 4 to 9).
a) Unmature stage: I.W.T. is less than 1,800. G.I. is the 0th to the 2nd grade.
The distinction between both sex becomes clear as the I.W.T. increases. To induce
spawning by artificial means is impossible at present.
*東北区水産研究所業績第297号
( 77 )
菊 地 省吾・浮 永久
b) Mature stage: L¥il/.T. is from 1,800 to 3,500. G.I. advances from the 2nd to the
3rd grade. To induce spawning by arti五cialmeans is possible from the latter half
of the stage. The amount of ejaculated sperm and spawned eggs are abundant.
c) Full mature st乱ge:I.W.T. is in excess of 3,500. The gonad is in the state where
all the characters indicating the gonad development show the highest marks and that
the maturity complete entirely.
Though it was cleared that th巴 maturityof this species advances as the I."W.T.
increases just the same as H. disι凶 l問 問削,thereis, however, a considerable difference
concerning the advancement of maturity between both species; it takes a longer time in this sp巴ciesthan in H. disι叫 h帥問削 ・toreach the full ma旬restage. Not only the
temperature but also the other factors such as the photoperiodical conditions should
be taken into consideration in order to reduce the term of practical rearing of the adult