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| Costa Rica |
Most of the Hong Kong people might have heard a country, Costa Rica, by watching the World cup, but I knew it from seeing a documentary that shown on Hong Kong Space Museum. It says that there is a large group of scalloped hammerhead sharks that swim shallowly around a remote island, Isla del Coco (Cocos Island).
Cocos Island 位於哥斯達黎加西岸，即位處中太平洋，距離哥斯達黎加海岸550公里(km)，一般船程要32至36小時。島上絕大部分地方由熱帶雨林覆蓋，而此島及其週邊海域自從1978年已成立為國家公園，島上現在只有少數林護員(park rangers)駐守，島上不設酒店，所以訪客都只可住在船上。島上最高的山峰有575米（M）。除了不准捕魚，還嚴格限制訪客數量，如現在只許2間公司經營4艘宿船到此島潛水旅遊，而且限制同一時間最多只有3艘宿船在此島範圍潛水及活動。而私人遊艇經事前申請也是可以到此停留。
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| Cocos Island aerial view |
Cocos Island is at the western side of Costa Rica, where is near the equator of the Pacific Ocean. It lies 550km west of Costa Rica. Visitors usually take about 32 to 36 hours travelling time by common vessels. It is coved by tropical rainforest mostly. As this island and its surrounding ocean have been declared as a national park since 1978, it only has park rangers on duty. There has no hotel, such that all visitors can only live on board. The government also implements a lot of regulations to protect this area, such as fishing is prohibited and she only licenses two companies with 4 commercial vessels that can operate tourist visiting regularly. The regulations also limit at most three vessels that may stay at this island area at the same time.
在這些限制下，保留了此島及週邊海域的原始風貌，除了在此前300多年來留下的歷史，所以亦不可說是原始狀態，特別是此島早期是由海盗佔領，他們給島帶來了外來生物如豬、羊、鹿、老鼠及貓等，給島上的鳥帶來新的捕獵者。過往有一個不能證實的傳說：島上有以前海盗留下的寶藏。亦曾經吸引人去尋寶，不過沒人成功過，當然現正己禁止尋寶了。
Under such protection, this island keeps its wild environment except the remains of pirates who had occupied and lived for three centuries, before the government has governed this island. Since the pirates had left, there had a rumour, which said that a treasure was hidden in somewhere. Nowadays, treasure hunting on island is prohibited of course. That the pirates bought introduced species to the island has been the most negative impact to the island, because birds have been hunted by them that did not have before.
過往我在外國潛水時和很多外國人傾談，說到理想的潛水性地，Cocos Island 是最常提及的名字。而距離680公里外的以達以文進化論聞名的加拉帕戈斯群島也是很有名。因受不同的水流的影響，加拉帕戈斯群島的水溫通常較Cocos Island 低很多，平均是22度攝氏，而Cocos Island 是25度。
In the past, when I talked with the foreign divers during overseas diving, they usually name Cocos Island as a dream place for diving. The second is Galapagos Islands where is just 680 km from Cocos Island. Because of having influence by difference currents, their water temperature has a large difference despite such close distance. In average, water temperature of Galapagos Islands is 22 degree Celsius while Cocos Island is 25 degree.
錘頭鯊為何在此處淺水出現？
其實錘頭鯊或雙髫鯊的分佈很廣，無論太平洋及大西洋，甚至紅海也看到他們出沒，但一般也只在深水或不常見。錘頭鯊可分為幾個品種，分別是 扇形雙髻鯊, 流線雙髻鯊, 細眼雙髻鯊, 巨雙髻鯊 及 窄頭雙髻鯊。我們今次看到的都是扇形雙髻鯊這一個品種。 |
| Scalloped hammerhead shark |
Why do hammerhead sharks come here and swim shallowly?
As hammerhead sharks are a widely spread species, they may be found in the Pacific ocean and the Atlantic Ocean, I even saw once in the Red sea, but they swam very deep. Hammerhead shark has five species, which are Scalloped hammerhead shark, smooth hammerhead shark, small eye hammerhead shark, Great hammerhead shark, and bonnethead shark. They were scalloped hammerhead shark that we saw during this trip.Cocos Island吸引牠們來，是因這裡是一天然「診所」（cleaning station)，如鯊魚或其他大型魚類生了寄生蟲或有損傷，珊瑚區很多時會有醫生魚(如黑鼻蝶魚,天使魚或各種濑鱼等)幫助鯊魚等魚類咬走寄生蟲及傷口死皮。這時錘頭鯊會游近水底礁，減慢速度及身體作出擺動，以通知醫生魚來。因鯊魚是軟骨魚是沒魚鰾，如牠們要保持某一水平便需不斷游泳，所以當鯊魚在交配中，會除除下沉直至到水底或完事。部分鯊魚甚至要不斷游泳以使水能流經鰓以呼吸。
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| Manta Ray |
Hammerhead sharks like other fishes may get sick or parasitic infection, so they need to go to underwater clinic periodically, which is cleaning station, where gathers many cleaner fishes, such as barberfish, angelfish, or wrasses, etc. They eat the dead skin of wound or parasites. When sharks come close to reef, they swim slow down and signal to the cleaner fishes. Because hammerhead shark is soft-bone fish that has no swim bladder, it needs to keep swimming all the time to maintain its level. Therefore, when hammerhead sharks are mating, both of them descend slowly to bottom, because they cannot swim and mate at the same time. Some shark's species even need to keep swimming for sucking sufficient water through their gills.
本來Cocos Island是一個全年都識合潛水的潛點，不過昨年(2018)是有點失色，因昨年正處於厄爾尼諾(El Niño)週期，這代表東太平洋水溫比平常高。我到達時發現水溫達攝氏27度，這不是牠們喜歡的水溫。所以數量比想像中是少了很多，特別是游近礁的數量非常有限。在這裡拍攝牠們的泳姿是最理想的，因說過牠們會游得較慢及接近鏡頭。根據不同的潛點，我們會停留在20至30米的深度，以守株待兔的方式等牠們游來。
雖然時間不對，因這地方是有保證，我們也能拍得牠們的近照。中間還看到其中一條身體給破魚網纏著，那些網都鎅入牠的背及尾鰭。
Since Cocos Island is at tropical zone, there can be diving year-round, but it was not the best season last year (2018) when I have dove, because there was during the cycle of El Niño that means the water temperature of east Pacific ocean is higher than normal. When we have arrived, we found that the water temperature was 27 degree Celsius that is too high for hammerhead sharks, such that the number of sharks was much less than my expectation. There were not too many sharks that swam closed to the reef where is the best place to take photo and video, as they swim slower. According to difference dive sites formation, we stayed between 20 to 30 meters depth to wait for their coming. Despite wrong timing, Cocos Island keeps its guarantee, as I could have taken some shots that they swam to me close enough. We also saw one poor hammerhead shark which has been being entangled by a fishing net and some lines have deeply cut into its dorsal and tail fins.
當地的魚明星
Cocos Island有一非常可愛及有趣的小魚，牠們以塗了超紅唇膏及以鰭行路而聞名。牠們在淺水的沙地生活，以小魚為食糧，雖然牠們多數時間是行路，不過牠們也懂游泳的，牠可擺動尾鰭來前進。而且牠們有一極大優點，是牠非常懂得擺post. |
| Rosy lip batfish |
Star of Cocos
Beside large fishes, there is a small fish that has sharp rosy lip, which like a woman who has lipstick's makeup, and walking by fins. This species can be spotted in Cocos Island and Galapagos Islands. They live on shallow sandy bottom and feed on small fish. Although they usually walk, they can swim by swinging their tail. They are also good in posting.深潛的體驗
娛樂潛水的最深深度是40米，任何正式訓練都提醒不能超越。如要挑戰，那便進入技術潛水，無論裝備及訓練都不同。在Cocos Island 營運的其中一間公司，特別訂做了一架主要作為娛樂用途的潛艇給未有機會挑戰深潛的人可親身體會水深三百米的環境。這公司的主要股東本身是一知名水底攝影師，船上特別預留私人房間，他幾乎是每個行程都會參加。他建做這潛水艇也有科研的考慮所以艇外亦有一機械手臂。而他亦因有這潛艇，得以發現一軟珊瑚家族(family)，並在2012在科學上證實，這新家族的第一個品種便以他的名字命名。 |
| DeepSea submarine |
Deep dive experience
The maximum depth of recreation diving is up to 40 meters. Diving instructors always tell not to excess this limit. If anyone wanted to challenge this limit, it would be technical diving that is required special training and equipments. One company that runs in Cocos Island built a submarine, which provides deep dive experience to anyone who doesn't have deep dive training. This submarine can be used by both recreational and researching purpose, so it is equipped with a robot arm and a high definition camera. Using this submarine, the founder who built this submarine found a new family of soft coral. After this exploration has been confirmed scientifically in year 2012, his name names to the first species of this family.這潛艇最重要的部分除了維生系統便是它四吋厚的膠圓球。這圓球制造時將密度調控至與海水一致。這目的是使人在水下時看不到這殼的存在。潛艇每次可載一個控員及兩個參加者，即最多三人。在科研時其中一人需要是機械臂操控員。
The most important part of this submarine is its spherical dome, which makes by 4 inches acrylic. When this dome was modeled, they controlled the density of acrylic is as same as sea water, such that the people do not realize its exist underwater. It may serve two guests with a pilot for each descending. When it is a researching purpose, one of them must be a robot arm technician.
我們潛水時，配帶的面鏡會把物件放大，但潛艇的球殼是把景物縮小三分一。
During diving, our mask enlarges the objects that we see, but the dome shrinks the object to two third of its original size.
雖然下潛時間不長，這潛艇亦從沒發生意外，不過每名參加者都要磅重及教授預到突發時的操作。磅重要計算潛艇的平衡，有差別便要加重物消除不平衡。他們是假設2大可能的意外，而是可即時人為控制的：
1. 如有電器漏電引發火警
2. 如操控員失去知覺，乘客怎樣接管控制權，及將潛艇升回水面。
當然我們是沒機會應用得上。
Safety is the most concern to the operators. They have been lucky that this submarine has never happened accident. Each guest must be weighed for adjusting the balance of submarine and given a briefing when an emergency occurs. This briefing tackles 2 situations:
1. Electric fire
2. If pilot were unconscious, how the passengers would take control to the submarine and surfacing.
Of course, we have never used these.
潛艇每次出發，其實是需要兩個操控員加一個助手，因在下潛時，潛艇內的操控員不斷要向水面的操控員報告船上的各項參數。而助手是幫潛艇解纜及幫參加者拍攝打咭照。水底通訊在幾百米的範圍內是可無線進行的，就像用全面罩配的通訊儀器一樣的技術。
Every trip, it requires two pilots to operate the submarine, one on surface and the other inside the submarine. Both pilots need to communicate frequently to report the monitoring data such as temperature, level of carbon dioxide and depth. The communication is through wireless that may transmit over several hundred meters. There is another assistant who works for attaching and detaching cables and taking photos to the guests from outside of the submarine.
這艘潛艇的設計可達的深度是超過四百米，不過娛樂用途時只會去到三百米，不過這深度已過了昏線(twilight zone)，如沒燈基本上是全黑，相機也對不到焦。
潛艇和水肺潛水的最大分別是它不用理會減壓，因倉內一直控制在一個大氣壓。所以我們不會吸入過量的氮氣，不用減壓停留，亦可用較快的速度上升。
The design depth of this submarine is 400 meters, but it only goes to 300 meters for recreational use. In this depth, it has been beyond the twilight zone that has no light. The difference between SCUBA diving and submarine is decompression. As the ambient pressure keeps at one atmosphere pressure, the absorption of nitrogen has no difference from on land, such that no decompression is required and the ascending rate is faster.
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| Frog fish |
This submarine uses two large bladders to control the ascend and descend and air is circulated internally, such that no air is emitted from the submarine, but it can be done if the pilot wants.
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| Jellonose fish |
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| Jellonose fish |
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| Jellonose fish |
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| Yellow conger eel |
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| Inside the submarine on surface |
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| Inside the submarine under 300m |
At this depth, colour of creatures has diminished except those live both shallow and deep. I hoped to see a large group of hammerhead sharks passing by us, ragged-tooth shark and prickly shark that only live in deep sea before the descend, but non of them has been seen. Fortunately, we saw some creatures that live in deep such as jellonose fish, frogfish and king crabs.
行程：
香港經洛杉磯再到哥斯達黎加首都聖何塞機場，在市內住一晚，翌日早上船公司派車接到碼頭(Puntarenas)上船，一般會在船上住十天。其間在島及週邊海域活動，有潛水，潛艇體驗遊及登島陸上行。
簽證：BNO需要，但如有美國簽証可豁免。特區護照免簽証，但如需過境美國也需有美國簽証。
Trip information:
We took flights to the capital of Costa Rica, San Jose, via Los Angeles and stayed one night. The operator hires an agent to pick up the guests on the day of departure between 8am and 1pm to the seaport, Puntarenas, where is the base of the vessels. Guests stay on the vessel for ten days usually and the operator offers Scuba diving, submarine experience and land trip to the island.
VISA: BNO holder needs visa, but it can be exempted with valid US' visa. HKSAR's passport doesn't require visa, but you also require an US' visa, if you transit through US' airports.
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