the fishermen beat out a warning signal. 渔民们发出了警告信号

267. ..and are raiding the fishing nets
     成千上万的海狮聚集在一起
268. in their thousands.
     掠夺渔网中的凤尾鱼
269. With the net almost drawn in,
     随着渔网被彻底收紧
270. the fishermen beat out a warning signal.
     渔民们发出了警告信号
271. Time is up.
     时间到了
272. In the confusion, not everyone manages to escape.
     在混乱中 有些海狮没能成功逃脱
273. The trapped sea lions are in danger of being drowned.
     被困在渔网中的海狮有被淹死的风险

来自《行星地球 第三季 第二集 Planet Earth S03E02 海洋》第 270 行