open access

https://hdl.handle.net/2115/76363

潮汐がサンゴ礁におけるリクエーション活動に及ぼす影響評価

英語

coral conservation

2015-03-15

VII, 58 p.

Coral reefs ecosystem has enormous value in marine diversity and contributes to recreational tourism growth in coastal areas. However, inappropriate recreationalist behavior warrants local concern about coral health, subsequently requiring reef friendly recreational activities. The study was conducted at Shimoji Island, Miyako Islands, Okinawa Prefecture of Japan with the aims of classifying depreciative recreationalists’ behaviors; conclude and suppose different damage patterns of behaviors in relation to tidal change; and provide recommendations to alleviate recreational damage for the sake of coral conservation as well as local sustainable development. The study consisted of three stages: the first stage including an in situ survey (September and October, 2013) and an inquiry survey of a local diving shop; the second stage being data analysis and developing suppositions of reef damage patterns (September to November, 2013); and the last stage of proposing recommendations on reef friendly recreational manners. Results of the in situ survey showed the most vulnerable coral species as Porites rus (69% of overall accounted broken coral branches) following by Porites cylindrica (accounting for 30% of the total damage), and Acropora muricata suffered the least amount of damage (only 1%). The damaged P. rus colonies were found close to the sea surface and its breakage mainly concentrated in the central and the edge of the colonies. This is considered as a direct consequence of sequential occurrence of depreciative behaviors by swimmers and snorkelers. The study consider that boots kicking is the initial damage that weakens the P. rus colonies’ tensile strength. It occurred when the depth between the sea surface and the surface of P. rus colonies (hereinafter refer to depth) was within the range of 100cm to 150cm. Based on the primary damage, behavior of standing upon reef colonies contributes to a massive and rapid expansion of breakage, which is perceived as the secondary damage which occurred when the depth was between 50cm to 150cm. Breakage of P. cylindrica colonies were mainly found in the middle-layer of the sea and its damage concentrated at the tips of the branches. The study considered that this is caused by tide-induced direct coral contact by divers due to the variation in the diving space, since subsequent occurrences of unstable current cause difficulties for divers in buoyancy controlling and thereby increases the contact potentially. Therefore, the shallow area has a relatively high frequency of the occurrence of coral contact, especially during the low tide period. Insufficient awareness and lack of comprehensive guidelines of recreational use towards reefs are considered as the main factors which lead to the existence of depreciative behavior patterns and the setting of notice boards of reef friendly manners is suggested. The notice boards are designed to provide information beforehand in order to raise recreationalists’ awareness towards their behaviors as well as the consequent impacts on coral reefs ecosystem. Besides, suggestions also emphasize the importance in being equipped with the proper gears and the necessity in pre-training for recreationalists. These counterplan suggestions are considered of great value in contributing to sustainable reef tourism in long term.

44282

修士(環境科学)

修士論文

Version of Record