- The Ichthyological Society of Japan
- 魚類学雑誌 (ISSN:00215090)
- vol.51, no.2, pp.135-147, 2004-11-25 (Released:2010-06-28)
The reproductive ecology and early life history of the bagrid catfish, Pseudobagrus nudiceps, were investigated in the field and laboratory. The species reproduced between late June and early August in a tributary of the Kinokawa River, Wakayama Prefecture. During the reproductive period, large mature males maintained a territory around crevices along shoals and banks. Mating behavior was observed there and in an aquarium, the field observations being the first for any Asian bagrid. When a female visited a male's territory, a series of behavioral activities, including courting, embrace and egg-stirring by the female were observed. Females (115-137mm SL) produced 1200-3000 developed ovarian eggs, apparently spawning in the nests of several males. Parental males cared for the eggs by fanning and cleaning, using the pectoral and pelvic fins, and displayed aggressive behavior against fish approaching the nest. Spawned eggs were adhesive and between 2.5-2.7mm in diameter. The eggs hatched 2.5-3 days after fertilization at an average water temperature of 26°C. At 2 days posthatching, the larvae began to move at night, leaving the nest after 7 days. Brood parasitism by the Japanese minnow, Pungtungia herzi, was frequently observed in the nests of Pseudobagrus nudiceps.