바다숲 조성에 따른 서식생물상 변동과 자원 조성 효과

Abstract

In order to evaluate the effects of seaweed beds on fisheries resources, field investigations were conducted at Jeju Island, Yeosu and Seosan during Fall and Winter, 2015. Populations and food-habits of benthos and marine fishes were used as indices for the development of fisheries resources. As a result, a total of 183, 152 and 63 species were found at natural seaweed beds, artificial seaweed beds and seagrass beds, respectively. Based on the standing crop per hectare, benthos were at rates of 9.9×106 individuals (2.1 ton) in natural seaweed beds, 16.1×106 individuals (3.7 ton) in artificial seaweed beds, and 2.7×106 individuals (356.5 kg) in seagrass beds. In addition, marine fishes were found at rates of 591 individuals (105.8 kg), 663 individuals (169.2 kg) and 1,026 (46.7 kg) in natural seaweed beds, artificial seaweed beds and seagrass beds, respectively. Considering results of food-habits analyses, predominant five marine fishes (white-spotted conger, marbled rockfish, dark-banded rockfish, javelin goby, and red tongue sole) found in seaweed beds were all carnivorous species consisting of ichthyophagous (white-spotted conger), polyphagous (marbled rockfish and javelin goby), and benthophagous (dark-banded rockfish and red tongue sole) species. This study indicated that the five fish species were mainly fed on the organisms inhabiting in seaweed beds. Thus, homing effects of marine fishes could be expected with the establishment of seaweed beds and consequential biomass increases of various food organisms. Based on the results in this study, the effects of seaweed beds on marine fisheries resources could be anticipated as follows; 1) firstly, benthic or grazing marine invertebrates onto seaweeds will inhabit once seaweed beds are established, 2) secondly, marine fishes that are fed on the invertebrates will more thong into the seaweed beds with the increased biomasses of the invertebrates, 3) lastly, the seaweed beds will provide marine fishes with spawning and nursery grounds and refuges, resulting in stable and sustainable marine ecosystems. Along with the establishment of marine ecosystems, follow-up management on artificial seaweed bed and extermination of harmful organisms should be properly implemented in order to sustain remediation of ecosystems and enrichment of fisheries resources. In conclusion, it appears that the establishment of seaweed beds could result in increasing biomasses of marine invertebrates and consequently homing marine fishes into seaweed beds. The results of this study could also provide useful background information for fisheries (recruitment and survival of fisheries resources) and/or social sciences (fisheries economics) for evaluating the scientific and economic values of seaweed beds.