The campaign groups, WWF and the British Antarctic Survey, believe any conservation effort must start with an accurate baseline assessment of the size of populations.

世界自然基金会和英国南极调查局表示，在进行任何保护措施之前，必须首先进行准确的种群规模基线评估。

In the 1960s, scientists proposed that predators at the top of a food web had a surprising amount of control over the size of populations of other species — -including species they did not directly attack.

在 1960 年代，科学家们提出，位于食物网顶端的捕食者对其他物种的种群数量有着惊人的控制力——包括它们没有直接攻击的物种。