서식처에 따른 아므르불가사리의 먹이 선호도 및 분포특성

Abstract

Predatory seastars are known to exhibit intense prey species selectivity, which is profoundly influenced by prey availability. However, prey availability is intrinsically dependent on geographical and local community variability, and this leads to the spatial variation in the extent of prey selection of seastars. The spatial variation in the extent of prey selection of Asterias amurensis was quantitatively assessed in the subtidal zone of Tongyoung in the central South Sea of Korea. The density of the seastar was estimated at 10 chosen sites included inner and outer part of the Tongyeong coast from December 2000. The mean density of the species in this area was 2.4 ind./m2. The seasonal surveys conducted at 3 arbitrary chosen sites (sea cage, reef and soft sediment) also showed that the abundance of the species at the sea cage site (density: 3.6 ind./m2; biomass: 250.7 gwwt/m2) was significantly higher than at the reef site (density: 1.7 ind./m2; biomass: 63.5 gwwt/m2) and the soft sediment site (density: 0.4 ind./m2; biomass: 18.9 gwwt/m2). At sea cage site, A. amurensis population exhibited a strong aggregated distributional pattern. In contrast, A. amurensis population showed a random distributional pattern at reef and soft bottom sites. The spatial difference in prey species and its abundance was the primary factor determining the spatial heterogeneity of the seastar in its behavior characteristics. Experiments on the feeding preference indicated that A. amurensis had a strong selectivity on its prey, but this selectivity varied between populations living in different sites. In particular, A. amurensis populations at the reef site showed a strong selectivity on various sessile and mobile animals living in reef areas, suggesting that these animal groups may play a role as \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'windows for the survival of A. amurensis\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\'. These results suggest that the distribution of A. amurensis in Tongyeong is closely as