Scientists don't know how large the Asian carp population would need to get before it becomes self-sustaining and morphs from nuisance into true threat.

科学家不清楚亚洲鲤鱼的种群规模达到多大时才能存活下来，并将骚扰变成真正的威胁。

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In theory the park's population should be self-sustaining by 2004.

ECONOMIST: Wildlife conservation: Animal farm | The

Once a movement gains enough adherents within a population, it is only a matter of time before its growth becomes self-sustaining.

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