| 英文摘要 |
The present project was launched early?this year by the Fisheries Agency to evaluate the effectiveness of artificial reefs (ARs) in waters off Tauryuan County (Chu-wei, Yeong-an), Hsinchu County (Hsin-feng II), Miaoli County (Chyi-ding, Wai-bu, Bair-hsin, Tong-shiao II), Taichung County (Wu-chia) and Hualien County (Chi-lai-bi, Yian-liao). So far we have successfully collected information on the present status of these 10 AR sites through totally 40 scuba dives. ARs observed during diving remained mostly intact. A total of 176 fish species in 97 genera from 39 families were observed. When the biomass of fishes was estimated based on number of individuals, the lowest biomass, namely 0.5 kg, occurred at Yeong-an reef site. Chu-wei site, with biomass weighted 0.6 kg, was the second lowest. Since the density of ARs was already high at these two sites, also with the relatively high sedimentation in the local waters, further AR emplacement will not be recommended for these two sites. While the average biomass was 8~23 kg for Wu-chia, Tong-shiao II, Hsin-feng II and Chyi-ding, it reached even higher (as 39~60 kg) at Bair-hsin, Yian-liao and Wai-bu sites. Nevertheless, the highest biomass occurred at Chi-lai-bi, where 105.7 kg was the average figure. Net casting was found on some ARs. More the 30% of net coverage occurred to the following reefs: concrete reef at Hsin-feng II, both A and B types of steel frame at Chyi-ding, and used electric utility poles at Wai-bu, Tong-shiao II and Wu-chia. Apparently net removal is urgently needed for these AR site to ensure a sustainable use of these ARs. |
