例如，海星捕食各种双壳类软体动物，防止这些双壳类动物独占海底的栖息地。

For example, sea stars prey on a variety of bivalve mollusks and prevent these bivalves from monopolizing habitats on the sea floor.

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不过，协定没有涉及到双壳贝类、水产品卫生和检疫问题。

However, it does not include trade of bivalves, fish health and quarantine issues.

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许多蛤类利用双壳及内部柔软强健足部的交替运动在河床上掘洞来逃避天敌。

Many types of clam escape predators by burrowing into the sea bed using alternating movements of their shell and of the soft, muscular foot contained within that shell.

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