Wednesday, August 05, 2009

The Amazing Eel


Found in some of the most unexpected places, the Spotted Eel is capable of moving over moist ground to get to other bodies of water. It also manages to climb up what would seem like impossibly high barriers such as weirs and waterfalls. This eel can be found in just about any watercourse in the Wet Tropics, including high altitude rainforest streams. The Spotted Eel (Anguilla reinhardtii), also sometimes called the Long-finned Eel, is pale or light brown with greenish spots over its upper body. Usually seen at about one meter (three feet) in length, they can reach more than two meters (seven feet) and weigh over 16kg (35 pounds) and are more thickset than exotic eels. This eel is curious and will come to the water's surface to have a look at you!

The life cycle of the eel is very different to most fish. Wet Tropics eels spawn in the Coral Sea and migrate as planktonic leptocephali to near-shore waters where they metamorphose as unpigmented glass-eels. They move into estuaries and then migrate upstream in response to floodwaters, to grow and develop through to small, fully pigmented elvers. Generally, the elvers which penetrate further upstream ultimately become females and grow to a larger size than males. Those which develop into males remain in estuaries and the lower reaches of streams. Sexually mature 'silver-eels' undergo marked changes in appearance and physiology and undertake a once-only downstream migration to the spawning grounds, where it is believed they spawn and die.

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