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Thursday, 6 August 2015

Compare and contrast

Compare and contrast

The freshwater longfin eels breeds only once, at the end of their life. When they are ready to breed, they leave New Zealand and swim 5000 kilometres up into the tropical Pacific to spawn, in deep ocean trenches somewhere near Tonga. When they reach their destination, the females lay millions of eggs.

The long finned eels life cycle starts off as an egg, it then changes into larva. After that it changes into a glass eel and then forms into an adult. Eels take many years to grow and it could be decades before an individual is ready to undertake the long migration back to the tropics to breed. The average age at which a longfin eel migrates is 23 years for a male and 34 for a female. The adults never return as they die after spawning.

The freshwater smelt life cycle is very similar, when the smelt adult is ready to reproduce it makes a spring then the egg comes out and the egg hatches as a whitebait, then starts to get bigger as it turns into an adult smelt.

Overall the Smelt and the Eel are kind of similar, ignoring the fact that their size difference is massive. They are both a New Zealand freshwater fish, and live in our local waterways and  their life cycles are both alike.

By Amy, Mason and Geordie

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