Dr. Chung Shan-shan recommends scuba divers to hold on to an area which is out of coral as shown in the photo during diving activities to reduce mechanical damage to the marine ecosystem


鍾姍姍博士建議潛水人士可以輕力扶著圖中顯示沒有珊瑚生長的地方,以減少對海洋生態系統造成的人為破壞

Date: 10 Dec 2013 (Tuesday)

Archive

HKBU's research quantifies impact of underwater behaviour of Hong Kong divers     Over 70% of scuba divers in contact with or damaged coral during diving activities

浸大公布「潛水對海洋生態的影響」研究     超過七成潛水者曾觸碰或破壞海洋珊瑚

A research project at HKBU revealed that about 72% of scuba divers, the majority of which were inexperienced and camera-carrying divers, were in contact with or damaged coral and marine substrate during their diving activities in Hong Kong, and thus had an impact on the marine ecosystem.

Dr. Chung Shan-shan, Assistant Professor of the Department of Biology, has been leading a research team in undertaking quantitative estimations of the impact of diving and the underwater behaviour of recreational divers on hard coral at seven major diving sites in Hong Kong.(Table 1) The results show that the major impact of diving activities on the marine ecosystem is mechanical breakage of coral, which can be caused by accidentally kicking, standing on and trampling coral surfaces by certain groups of divers. The most harm-inflicting groups found in the study were inexperienced and camera-carrying divers.

In the study, Dr. Chung and her team recruited experienced divers as volunteers to conduct direct observation of recreational diving activities to understand the underwater behaviour of scuba divers. All divers participated in a questionnaire survey after they had finished their diving exercises. Data were collected from June to November 2010, during which 81 scuba divers, mostly aged between 20 and 34, and more than 127 diving expeditions were directly observed.

Of the 81 divers observed, 30% were not yet certified. The remaining 70% had diving experience ranging from 1 month to 35 years and the majority of them did less than 10 dives per year.

The results found that on average, a diver was in contact with marine substrate 14.7 times per dive and 74% of contacts were unintentional. About 40% of contacts involved coral; in other words, a diver was in contact with coral 5.9 times per dive on average. Of these, 38% were damaging contacts with coral or other living organisms in a single dive. The most frequent form of contact was divers’ flippers. Damaging contact included kicking, trampling and collision. Other impact of diving activities included touching of coral by hand or contact by the scuba unit leading to lesions on coral tissues. (Table 2)

In order to take good pictures, divers need to stabilise themselves underwater by holding on to a fixture, which often happens to be coral. The study showed that camera-carrying divers made contact with marine organisms an average of 23.8 times per dive while divers without cameras made 11.6 contacts per dive. It can be concluded that divers who carry cameras make more contact with marine organisms than those who do not carry cameras. Although divers’ self-assessment in their post-diving questionnaires portrayed the reverse situation, with the majority of divers perceiving that they had less impact than they actually did.It wasalso discovered that most of the divers who underestimated their inflicted damagewere beginners who are generally less aware of the impact of their diving.

Therefore, there is an imminent need to assess the scale of damage from diving activities on the marine ecosystem given the rapid development of marine-based tourism and the limited coral-inhabited areas in Hong Kong as the marine environment is already under stress from human activities.

Dr. Chung said: “While this study reveals the potential damage inflicted on the marine ecosystem in Hong Kong, it is only a snapshot of the big picture and yields little information about other related important issues such as coral breakage rates, the most vulnerable coral types, the effect of improved diving education or intervention by diving guides, and regenerative capacity of various types of coral upon accidental human damage.” She added that the low water visibility and the need to follow the entire diving expeditions hampered the ability of the research observers to keep more detailed records of the divers’ underwater behaviour and their impact on coral.

Dr. Chung suggests to the HKSAR Government that areas with substantial number of coral colonies in shallow water should be zoned as areas prohibited to divers. She recommends that diving expedition organisers should make it mandatory to include conservation messages during their pre-dive briefing sessions. In addition, dive guides and dive masters should be required to attend environmental conservation training at regular intervals. She added that training for novice divers should be limited or confined to areas which are safe and non-environmentally sensitive.

浸大一項研究發現,超過七成(72%)本港潛水人士在潛水時曾經觸碰或破壞珊瑚,其中初學者和進行水底攝影的潛水者佔大多數,對本港的海洋生態造成一定的影響。

生物系助理教授鍾姍姍博士率領研究團隊,在本港七個主要潛水熱點進行調查、下潛觀察並量化統計休閒潛水人士的水底行為對海洋珊瑚造成的影響(圖表一)。研究調查發現潛水活動對水下生態的主要影響是珊瑚結構受到人為破壞,包括部分潛水人士因不小心踢到海床或無意中踐踏而踢爛珊瑚表面。當中,初學者和進行水底攝影的潛水人士令珊瑚受較嚴重的破壞。

鍾姍姍博士及團隊招聘資深潛水人員為義工,下潛直接觀察並記錄休閒水肺潛水者的在整個潛水活動中的行為,所有潛水者完成活動後均需填寫問卷。調查由二零一零年六月至十一月期間舉行,觀察了81位水肺潛水者、共127次下潛活動。大部分潛水者年齡界乎二十至三十四歲。

在81位潛水者中,三成並非合格的潛水員,其餘七成(58人)是合格的潛水人士,擁有一個月至三十五年潛水經驗,大部分人士每年下潛次數少於十次。

結果顯示,每位潛水者每次下潛平均觸碰海洋生物14.7次,近74%屬不小心觸碰。約40%觸碰涉及珊瑚,換言之,每位潛水者每次下潛平均觸碰珊瑚5.9次。當中,38%是在單一次下潛時對珊瑚或其他海洋生物造成損壞性的觸碰。觸碰次數最多的是潛水者的「蛙鞋」﹔損壞性的觸碰包括踢、踐踏和碰撞。其他影響包括用手接觸或潛水裝備觸碰到珊瑚而導致珊瑚組織破損(圖表二)。

潛水人士有時為求在水中穩定身體以拍攝最佳照片,會手扶水底物件幫助平衡,珊瑚通常成為他們的把手。研究顯示,進行水底攝影的潛水者每次下潛平均觸碰海底底床23.8次,不攝影的潛水者則是11.6次。由此可見,進行水底攝影的潛水人士比不攝影者觸碰海底底床(包括生物)次數較多。然而潛水人士往往會低估自己的行為對海洋生態造成的影響。研究又發現那些低估自己的潛水活動影響海洋生態的人士,大部分是潛水初學者,他們通常較少察覺潛水活動會為水下生態帶來影響。

本港以海洋為本的旅遊業急速發展,但珊瑚的棲息地方卻有限,人類的活動已令海洋環境承受沉重的壓力。因此,團隊認為有急切需要評估潛水活動影響海洋生態的程度。

鍾姍姍博士說﹕「這項研究反映了本港海洋生態系統承受的潛在破壞,但這僅是問題的一小部分,還未有充分資料展示其他重要的事項如珊瑚破壞率、最易受損的珊瑚種類、改善潛水訓練或潛水教練作出干預下的影響,以及不同珊瑚種類受到意外的人為破壞後的再生能力等。」她表示,海水混濁,能見度低,以及調查人員需下潛觀察整個潛水活動,都足以影響調查人員能否詳細記錄潛水人士的水中行為及其對珊瑚的影響。

鍾博士建議政府把淺水珊瑚區列為禁止潛水活動區域。至於潛水旅遊經營者,她建議把保育訊息定為每次在潛水前簡介中必須提及的事項,而潛水教練或導師亦應定期參加保育訓練。她又建議初學潛水人士只應在不影響水下生態的區域下潛。