Investigations on Fishery Resources and Ecological Sensitive Areas of the Southsea Four Islets of Penghu Archipelago

Project Duration	2011-02-28 ~ 2011-12-29
Research Title	Investigations on Fishery Resources and Ecological Sensitive Areas of the Southsea Four Islets of Penghu Archipelago
Contracted Organization	Penghu Marine Biology Research Center, Fisheries Research Institute, Council of Agriculture, Executive Yuan
Principal Investigator	Tsai Wan-Sheng
Co-Principal Investigators	Chung Chin-Shui, Hsien Yi-Leh, Chu Yun-Wei, Yi Yi-Cheng
Project Participants	Lin Hsiu-Mei, Huang Wen-Ching, Cheng Ching-Yi, Tu Shih-Yun, Ou Li-Chen, Hung Sheng-Wen, Lin Hung-Chuan, Wang Chih-Wen
Keywords	Penghu Southern Four Islands, fishes, fish larvae, zooplankton, fishery status
Abstract	I. Background The surrounding waters of the Penghu Southern Four Islands, proposed as a Marine National Park, previously lacked comprehensive fishery-related status surveys. II. Results 1. Using handline fishing methods, a total of 765 individuals representing 78 species from 22 families were recorded. Dominant species included Nemipterus virgatus (29.02% of total catch), Choerodon azurio (8.89%), Parupeneus multifasciatus (8.37%), Epinephelus merra (7.45%), Diodon liturosus (3.66%), and Cephalopholis boenak (3.53%). 2. A total of 1,955 fish larvae representing 178 species from 64 families were collected. Dominant species included Sardinops sagax, Cyclothone pseudopallida, Ceratoscopelus warmingii, Mullidae gen. sp., Gempylus serpens, Auxis sp., and Sarda sp., together accounting for 41.64% of total larval abundance. Species richness was notably higher than in other Penghu waters. 3. Among 198 recorded vessel operations, fishing activities were categorized into hook-and-line gear, net gear, and recreational yachts (snorkeling and diving). Bottom longline fishing accounted for 148 vessel trips (74.8%), representing the highest proportion. Fishing grounds were mainly distributed along the coastal waters of each island. Around Dongyu Ping and Xiyu Ping, fishing locations followed the 20-meter isobath contour. Around Dongji and Xiji Islands, fishing activities were concentrated near Dongji Island. 4. SCUBA surveys were conducted at 21 stations around the four islands. A total of 200 fish species from 38 families and 119 coral species from 13 families were recorded. After evaluation, the waters within the 15-meter isobath around Xiyu Ping were identified as the most suitable site for establishing a conservation zone, followed by the waters between northern Xiyu Ping and Toujin Islet. 5. Community interviews were conducted in April and August 2011 within the Southern Four Islands, focusing on community development, livelihoods, fisheries activities, living issues, external environmental impacts, and residents’ opinions on establishing a Marine National Park. From September to November, additional questionnaires were administered to relocated residents in Magong regarding their historical fishing activities in the area. III. Major Recommendations 1. Immediate Actions (1) To mitigate anchor damage to coral reefs along the northeastern coast of Xiji Island, northern coast of Dongji Island, and southeastern coast of Dongyu Ping, it is recommended to install mooring buoys for operational vessels to reduce habitat destruction. (2) Continued monitoring and possible manual removal of crown-of-thorns starfish populations are recommended, particularly in eastern Xiji Island waters. 2. Long-Term Recommendations (1) From a fisheries management perspective, long-term and in-depth research on the early life history stages of fishes in the survey area would greatly benefit resource management. (2) Further research should assess the impacts of gillnet fisheries on coastal fishery resources and habitats to determine whether such gear is appropriate for operation in these waters. (3) The Coast Guard Administration should strengthen enforcement and anti-poaching patrols or coordinate with relevant agencies to reduce and prevent illegal fishing activities. (4) To examine spatiotemporal changes in coral communities—given their uneven and patchy distribution—permanent monitoring plots should be established in conservation hotspots or existing stations to reduce sampling error and effectively monitor coral health.