| Summary: | 碩士 === 國立海洋大學 === 水產養殖學系 === 91 === The life history of Anguilliformes fishes is a mystery for us. There are not many studies about the reproduction of muraenids have be done. Evidently, the species and the number of moray eels becomes lesser and lesser nowadays in Taiwan. It is because of the ruining of worldwide environment, sea and seacoast incur pollution and over-fishing. With the purpose to sustain diversity of fishes and natural resources of fishery can be forever utilized, we need to study their reproductive biology, behavior, and embryonic development.
Siderea picta (Ahl, 1789) and thyrsoidea (Richardson, 1845) belonging to Muraenidae, are economic fishes in Taiwan. We try to keep the morays in aquaria for study, so we can breed them for a period observation and record the sexual development, duration of reproduction and the spawning behaviors.
In our aquaria, the reproductive season of the female S. thyrsoidea are not obvious. Every 1-2 month, the mature female were readily distinguished from the others by their extremely swollen, flaccid abdomen. It real bosom ripe eggs in the abdominal cavity and will keep about 4-6 days for the swell abdomen to eliminate distension. The eggs may be hydration apparently occurring before spawning. The courtship behavior mostly occur about 10:00 pm to 02:00 am. The reproductive activities seem to fit the cycle about fifteenth day of the lunar calendar.
According to the records of the video camera, the male S. thyrsoidea were exhibiting an apparent searching behavior, moving to the female in the courtship. The male slightly bite on the upper or lower jaw of the female, the initially uncoordinated rise quickly turned into a rush. Male S. thyrsoidea had strong territory and attack behavior during the reproductive period. Usually, the male will attack the other male until a serious injure excluding the female. We are conjecture the reproduction of S. thyrsoidea is one female to one male strategy.
S. picta and S. thyrsoidea could spawn naturally in our aquqria. The natural spawning and fertilized eggs of S. picta were found to occur at 20:00-22:00 pm and 00:00-02:00 am. The eggs were spherical, buoyant, transparent, and large (3.42 ± 0.13 mm in diameter of S. picta). In our estimation, the number of female S. picta ovulate once about 7081 ± 546 eggs. At the water temperature of 24 ℃ and salinity of 33 ppt, the fertilized eggs were hatched about 96-120 h. after spawning. The mean total length of newly hatched pro-larvae are 6.79 ± 0.41 mm. The pectoral fins can be found after half-day-old larvae from hatching. It is quite different from the adult character without pectoral fin apparatus. Larvae survive 10 days without obviously feed ingestion. The embryonic and larval development of S. picta are described in detail including the video records.
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