Friday, May 01, 2009

The disappearing eels

Eels in crisis after 95% decline in last 25 years | Environment | The Guardian

I wonder if Australian eels are still abundant: I know I saw a good number of them in the pond in the old botanic gardens in Brisbane a couple of weeks ago.

Anyhow, I suppose most people know about the remarkable life cycle of eels? Just in case you don't, here's the Guardian's summary:

The eel remains one of the world's most mysterious creatures. It is generally accepted that European eels - Anguilla anguilla - are born in the Sargasso Sea near Bermuda.

As leaf-like larvae, they are swept by the Gulf Stream towards Europe, a journey that may take a year. When the larvae reach the continental shelf they change into "glass eels" and in the spring begin to move through estuaries and into freshwater.

The animals develop pigmentation, at which point they are known as elvers and are similar in shape to the adult eel. Elvers continue to move upstream and again change colour to become brown or yellow eels.

When the fish reach full maturity - some can live to 40 and grow to 1m long - they migrate back to the ocean. Females are reported to carry as many as 10m eggs. They return to the Sargasso Sea, spawn and die.

Australian eels apparently spawn in the Coral Sea near New Caledonia. It seems odd that there still seems some uncertainty about this.

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