크리스마스섬의 홍게

요며칠 부쩍 관심이 가는 곳 시리즈 1탄! - 크리스마스섬의 홍게

 

하기 정보는 http://www.christmas.net.au/parks/crabs/index.htm (크리스마스섬 관광청? 홈페이지에서 일부를 발췌한 것임. 크리스마스섬은 인도네시아 아래 인도양에 둥실 떠 있는 호주령의 작은 섬으로, 퍼스에서 4시간, 싱가포르에서 2시간, 발리에서 1시간 30분 비행기를 타야한다.

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The Annual Migration To The Ocean

At the beginning of the wet season (usually October / November), most adult Red Crabs suddenly begin a spectacular migration from the forest to the coast, to breed and release eggs into the sea. Breeding is usually synchronized island wide. The rains provide moist overcast conditions for crabs to make their long and difficult journey to the sea. The timing of the migration breeding sequence is also linked to the phases of the moon, so that eggs may be released by the female Red Crabs into the sea precisely at the turn of the high tide during the last quarter of the moon. It is thought that this occurs at this time because there is the least difference between high and low tides. The sea level at the base of the cliffs and on the beaches, where the females release their eggs, at this time varies the least for a longer period, and it is therefore safer for the females approaching the water's edge to release their eggs. Sometimes there are earlier and later migrations of smaller numbers of crabs but all migrations retain this same lunar rhythm.

Possible spawning dates for 2005 are around October 27th, November 26th, or December 27th. The timing of the actual event is dependant on when wet seasons rains set in. The downward migration, dipping, mating, and egg-brooding sequences occur before the females spawn. These events occur in the 4 weeks preceding spawning. You cannot poinpont the exact date on the start of the migration before spawning, eg, downward migration can vary between 9-18 days, dipping can vary from 0-11 days - all dependant on weather.

The main migration commences on the plateau and can last up to 18 days. Masses of crabs gather into broad "streams" as they move toward the coast, climbing down high inland cliff faces, and over or around all obstacles in their way, following routes used year after year for both downward and return migrations. Movement peaks in the early morning and late afternoons when it is cooler and there is more shade. If caught in open areas, in unshaded heat, the crabs soon lose body water and die.