Spawning behavior and
artificial fertilization in captive reared red spotted grouper, Epinephelus
akaara
S. Okumura, K. Okamoto, R. Oomori, A. Nakazono-2002
Aquaculture, 206(3-4): 165-173
Abstract:
Spawning behavior was observed in the red spotted
grouper, Epinephelus akaara, to investigate the reason for low
fertilization rates in spawning tanks. Artificial fertilization was also
carried out to examine the egg quality of tank-reared fish. Grouper dashed
in a pair vertically from the bottom to the water surface and released
gametes at the surface. The pair sometimes jumped from the surface and swam
horizontally on the water surface before or after spawning. The mean
artificial fertilization rate (84.3%) was significantly higher than the rate
of the spontaneous spawning in the tank (19.0%). The low tank fertilization
rate may be due to limited space, especially insufficient water depth, which
may have inhibited normal spawning behavior.
(Tamano Station, Japan Sea-Farming Association,
Tamano, Okayama 706-0002, Japan, Tel.: +81-863-32-3935; fax:
+81-863-32-1301, e-mail: shigenobu-okumura@jasfa.or.jp)