Four of the world's 10 biggest freshwater fish migrate up the Mekong to spawn.

世界十大大型淡水鱼中有四种会迁移至湄公河产卵。

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This allowed natural gas to migrate up the hole and explode at the surface.

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The Angling Trust said it was disappointed after none of 72 fish electronically tagged negotiated the barrage to migrate up river to spawn.

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What is more, it may well be wrong to assume that if planning permission is denied for offices and houses in the south, jobs will migrate up north.

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