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標題: [鯨豚保育] 港大研究:珠三角白海豚瀕絕種
  本主題由 Xoni 於 2017-2-25 13:37 設置高亮 
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發表於 2017-2-25 13:35  資料 文集 短消息 
港大研究:珠三角白海豚瀕絕種

2017年2月25日 星期六

【明報專訊】港大最新研究顯示,於珠三角水域棲息的中華白海豚面對比想像中嚴峻的威脅。研究團隊指出,中華白海豚數量以每年2.5%的速度下滑,現時或已跌破2000條;該水域內的海岸保護區亦未能確保白海豚有足夠棲息地維持足以傳宗接代的數量;若不立即採取可顯着逆轉趨勢的保育措施,相信白海豚將會絕種(deemed to become extinct)。

該研究由港大生物科學院副教授賈力誠(Leszek Karczmarski)及兩名博士生合作,為全球首個針對沿岸海豚的研究,昨於科學期刊Scientific Reports刊出。

現料已不足2000條

研究團隊估算,撇除人為因素影響,白海豚的「可行存活數量」為2000條,假設海豚數量穩定,同時有3000平方公里可找到足夠食物和保護的「關鍵棲息地」,白海豚可存活最少40個世代、即大約800年。本港白海豚關鍵棲息地主要為大嶼山南部和西南部海岸,這些淺水區的範圍和連接度均影響海豚存活。本港及內地的海岸保護區總共只有600平方公里,當中極小部分涵蓋白海豚關鍵棲息地,未能確保白海豚維持可行存活數量的生態所需。

此外,珠三角水域的白海豚數量以每年約2.5%的速度下降,研究引述2008年的統計資料,當時約有2500條白海豚,即約9年便會跌至約2000條,以此推算,目前可能已經跌破可行存活數量。賈力誠指出,保育措施應集中保護白海豚的主要棲息地。他補充,除非有有效保育措施可顯著逆轉白海豚數量下滑趨勢,否則珠三角水域的白海豚將面臨絕種。

漁護署:計劃設更多海岸公園助保育

漁護署回覆表示,中華白海豚主要集中在大嶼山一帶水域,2015年在大嶼山西南、西、西北及東北四個調查區的數量估計為65條;過往數年的數據顯示,海豚在本港水域內的活動範圍改變,部分轉移或擴展其活動範圍至內地水域。署方稱,政府計劃加快設立更多海岸公園,以保護本港水域海豚棲息地,包括去年底設立的大小磨刀洲海岸公園,以及預計分別於2018及2019年設立的西南大嶼山及索罟群島海岸公園,料可大幅增加法定保護的重要海豚棲息地,確保其在本港水域繼續繁衍。

http://news.mingpao.com/pns/dail ... 00002/1487959632689

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pyling   2017-2-26 08:10  種子  +10   感謝分享 Thanks for sharing !
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Xoni
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發表於 2017-2-25 13:36  資料 文集 短消息 
關鍵棲息地不足 欠法例保護 
珠江河口 白海豚恐滅絕

2017年02月25日

【本報訊】中華白海豚是香港1997年主權移交中國時的官方吉祥物,但香港政府似乎未有珍視這種國家一級保護動物,吉祥物前景越來越不祥。香港大學最新研究指珠江河口沒有足夠的「關鍵棲息地」,讓中華白海豚尋找足夠食物及保護,本港更只有少於17%的海豚出沒核心海域,是受法例保護。港大專家表示,除非有有效保育政策拯救海豚,否則珠江河口的中華白海豚相信會滅絕。記者:陳沛冰

香港大學太古海洋科學研究所於《Scientific Reports》發表最新研究,指出撇除人為因素,若要維持2,000隻海豚生存,應有約3,000平方公里的「關鍵棲息地」,給予海豚可尋找足夠食物、保護及日常生活所需,可令2,000隻海豚生存超過40代,即約800年。本港的海豚關鍵棲息地,主要包括大嶼山南面及西南面海岸。

現僅餘65條

但研究指現時本港只有少於17%的海豚出沒核心水域,及少於7%的海豚覓食核心水域是受法例保護,內地受法例保護的海豚出水核心水域面積更少。
本港及內地只有約600平方公里水域屬於海洋保護區,香港政府規劃的海洋保護區,只覆蓋很少海豚出沒核心水域,所有珠江河口的海洋保護區於提供棲息地予海豚都是「失敗」(fail)。珠江河口的中華白海豚每年減少約2.5%。

參與研究的香港大學生物科學學院副教授Leszek Karczmarski表示,除非有有效的保育政策能將海豚數目扭轉,否則珠江河口的海豚相信會滅絕(extinct)。保育政策並非單單增加海豚棲息地的數量,而是要確保海豚尋找食物及保護的核心水域受保護。

香港海豚保育學會學術顧問洪家耀表示,近年本港4個主要水域,大嶼山東北、西北、西南及西面的中華白海豚數量大減,由2013年的188條減至2016年的65條,減幅達65%;而2010年珠江口連本港約有2,500條中華白海豚,相信數量也已大減。

洪表示,珠江河口的中華白海豚大減,主要由於基建及填海工程大增,如港珠澳大橋及機場第三條跑道。單以香港中華白海豚下降趨勢,「我哋可能有生之年,再見唔到香港嘅海豚」。他認為政府應盡快於大嶼山西面規劃海岸公園,令海豚有更多可使用的棲息地。

http://hk.apple.nextmedia.com/news/art/20170225/19939721
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發表於 2017-2-25 13:37  資料 文集 短消息 
A new study by HKU researchers paints a bleak future for the Chinese white dolphins in the Pearl River Estuary

24 Feb 2017

Researchers at the University of Hong Kong conducted first of its type demographic study of the Chinese white dolphins inhabiting the Pearl River Estuary and say that the dolphins face a far greater threat than previously thought.  The current demographic trajectory of the population and the ongoing loss of their critical habitats leave only a slim chance to prevent their stochastic extinction.  For conservationists and management authorities, the time to act is now.

In the day-to-day practice of protecting threatened species and populations it is important to know the natural limits, the demographic and ecological threshold of their long-term survival.  Because long-term survival of free-ranging populations depends on the carrying capacity of their habitat, the demographic and ecological threshold values represent the minimum population size that can be long-term viable and the minimum area of critical habitat that has to be maintained to secure a long-term survival of the minimum viable population.

These issues become particularly important for populations that face severe anthropogenic impacts, such as the Chinese white dolphins in waters of the Pearl River Estuary (PRE).  The natural stochastic fluctuations of their environment are magnified by human impacts and escalate to levels that may impair their survival.  It is not just the bare numbers, not just how many dolphins are in the area, but rather a dynamic network of interactions between the animals and their environment that determines the long-term survival of a species.  Therefore accurate estimates of demographic and ecological thresholds of a population are critically important in designing effective conservation strategy.

For elusive animals such as dolphins and whales, such estimates are notoriously difficult to generate because of the inherent difficulties of collecting sufficiently robust demographic datasets.  It takes many years of tedious data collection to build the minimum scientific evidence needed for such analyses; which is why very few attempts of such work have ever been done.  A new study by researchers from the Swire Institute of Marine Science, the University of Hong Kong undertook this challenge for the Chinese white dolphins inhabiting waters of the Pearl River Estuary and the study has just been published (February 23, Thursday) in the journal Scientific Reports (link: http://rdcu.be/pyc8).  It is first such study of coastal dolphins anywhere in the world.

The research was led by Dr. Leszek Karczmarski, Associate Professor at the School of Biological Sciences, and was co-authored by Dr. Shiang-Lin Huang, a former post-doctoral associate, and Mr. Stephen Chan, a Ph.D. student in Dr. Karczmarski's Lab.  

The team estimated that, if human impacts were to be excluded and the population was stable, approximately 2,000 dolphins would represent a sufficiently viable population and, if given access to approximately 3,000 km2 of their undisturbed critical habitat, such population could persist across at least 40 generations (approximately 800 years).

The so-called "critical habitat" is the type of habitat that dolphins use for their daily needs; these are the areas where they find sufficient amount of food and shelter.  In Hong Kong, it is primarily alongside the natural coastline of south and southwest Lantau Island.  The amount and connectivity of this shallow-water habitat affects dolphins' survival; the less of the critical habitat there is the lower the likelihood of dolphin survival.

However, currently the PRE dolphin population is declining approximately 2.5% per year and is fast approaching its viability threshold.  At the same time, all current marine protected areas (MPAs) in the PRE fail to secure the minimum habitat requirement to accommodate sufficiently viable population size that could withstand the ever-growing anthropogenic pressures.

Cumulatively, all current MPAs in both Hong Kong and Mainland waters cover just about 600 km2 and very little of it represent the dolphin critical habitat.  Dr. Karczmarski referred to a recent study by Miss Carmen Or who last January completed her Ph.D. degree under his supervision, and pointed out that in Hong Kong less than 17% of the dolphins’ core areas and less than 7% of their core foraging grounds are under legal protection; and in Mainland waters this ratio is even smaller.  Furthermore, he says, "most of the areas currently considered by Hong Kong authorities for the designation as MPAs include very little of the dolphins’ core areas and even less of their primary foraging grounds".

"To be effective - he says - conservation measures should not only increase the volume of the habitat under protection but, importantly, focus the conservation effort on the core areas and key habitats used by the dolphins for their daily needs.  Preserving the ecological integrity of those areas should be among the primary conservation targets."  

Unfortunately, he adds, "our findings indicate that the PRE dolphin population is deemed to become extinct unless effective conservation measures can rapidly reverse the current population trend".

Acknowledgement:   The study was supported by the Research Grants Council of Hong Kong (RGC) and Ocean Park Conservation Foundation Hong Kong (OPCFHK).  

For media enquiries, please contact Dr. Leszek Karczmarski, Associate Professor, The Swire Institute of Marine Science, School of Biological Sciences, Email: leszek@hku.hk.

http://www.hku.hk/press/press-releases/detail/15971.html
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pyling (快樂的小魚兒)
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發表於 2017-2-25 23:02  資料 短消息 
Finally!!!!!! Next step of this research is to talk to the people in the government and urge them to plan accordingly!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Whoever wrote such horrible press release article at the HKU should be retrained:
1. The link to the paper doesn't work. This is the correct link: http://www.nature.com/articles/srep42900
2. The journal is not just "Scientific Reports"--the main point is that it is published by Nature.
3. This study is definitely not the "first such study of coastal dolphins anywhere in the world". What an obnoxious and ignorant statement! Here is another study of Chinese White Dolphin published in 2015, for example: http://www.nature.com/articles/srep08147
4. The writer is sexist or just being ignorant in addressing people by their correct title: "Dr. Karczmarski referred to a recent study by Miss Carmen Or who last January completed her Ph.D. degree under his supervision"-->First, in academia, female non-PhDs are referred to as "Ms." and NEVER "Miss"; second, it should be Dr. Carmen Or!!! Is the writer making sense here? The exact SAME sentence says she has already completed her PhD. The writer still does not address her as Dr. Carmen Or, but an offensive title "Miss".

I am so disappointed that the HKU is using such poor writer in their press release.

[ 本帖最後由 pyling 於 2017-2-25 10:15 編輯 ]
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