Seasonal change of egg size and number in the anemone fish, Amphiprion clarkii, at two different localities in the temperate Kyusyu, Japan
2006
Aratake, H.(Kyushu Univ., Fukuoka (Japan)) | Nakazono, A.
The anemone fish, Amphiprion clarkii, is monogamous and spawns adhesive eggs in mass nearly at the same place, repeatedly during the warm months. The egg mass is laid on a flat hard substratum protected by the tentacles of host sea anemone in one layer. This enables to count the total number of eggs in an egg mass after taking photography. These characteristics provide a good material to study seasonal changes of egg production by a single female in temperate reef fishes. In the present study, egg numbers of clutches and egg sizes were monitored at two different places, one is at the southern end of Kyushu (Bohnotsu: 10 pairs) and the other was at the western end of Kyushu (Ushibuka: 12 pairs). The average water temperatures were slightly higher at B than U. Water temperature ranged 18.9-21.7 deg C at B and 20.5-23.4 deg C at U and the beginning of spawning differed by pairs. The latest spawning also differed by pairs and confirmed to be at 25.7-29.3 deg C at B and at 24.2-27.8 deg C at U. The number of spawning was 6-11 times at B and 4-8 times at U, by pairs. The number of eggs spawned at one time by females was 1,925-5,989 at B and 483-5,535 at U were larger in the early part of spawning season and egg sizes were apt to be larger during this period than the rest of the spawning season. But, at B, where spawning season was slightly longer than U, the egg sizes showed a tendency to become larger again at the end of the spawning season.
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