ニジカジカAlcichthys alcicornisの生殖周期と産卵生態
1994 年 41 巻 1 号 p. 39-45
詳細
1994 年 41 巻 1 号 p. 39-45
Histological observations of the ovaries, statistical analyses of catches by trammel net, and obser vations of territorial males and egg masses by SCUBA diving were made in order to clarify the reproductive biology of the elkhorn sculpin, Alcichthys alcicornis. Ovarian development was categorized as immature (July-December), yolk accumulation (January-March), copulation and spawning (April-May), or degeneration (May-June). Sections taken from mature ovaries showed A. akicornis to be a multiple spawner, ovulating and spawning several times in a single breeding season. Trammel net catches during the breeding season suggested that members of the breeding population migrate synchronously by sex from offshore depths to shallow waters, males preceding females by 1 week (in late March-mid April); females achieve initial spawning by late April. Breeding sites were found in cracks or crevices between rocks within territories established by territorial males. At least 80-100 egg masses were deposited in each territory during the overall spawning season. The occurrence or otherwise of sneaking tactics during copulation in A. alcicornis is discussed.
