VOA常速英語：最新無人機(jī)技術(shù)可幫助牡蠣養(yǎng)殖場保持滿倉

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As marine farming grows worldwide, there is an urgent need to study the effects—both positive and negative—on the local ecosystems. Deana Mitchell visits Tomales Bay in Northern California where researchers are using the latest drone technology to investigate.