Shortly after 12.45pm, what remains of a 300-metre line goes taut(拉紧的). Somewhere beneath the murky(浑浊的) green surface of Delaware Bay, on the eastern US coast, a sand tiger shark has taken the bait(鱼饵) of a mackerel chunk. Marine researchers at the University of Delaware haul(拉，拖) the line towards a small boat as the shark’s grey-brown outline emerges.
下午12点45分刚过，一条300米长的延绳钓剩余部分绷紧了。在美国东海岸特拉华湾浑浊的绿色水面下，一条沙虎鲨咬住了鲭鱼块做的饵。特拉华大学的海洋研究人员把钓线往小船方向拉，鲨鱼灰褐色的轮廓随之浮现。
It is a large animal: 225cm (7ft) long with a 90cm girth(腰围，周长). Its mouth hangs open, revealing rows of jagged(锯齿状的) teeth. The researchers work quickly, measuring the shark, recording its sex, and taking blood and muscle samples. A tag is then fastened beneath its dorsal fin(背鳍), through its thick sandpapery skin(砂纸般的皮肤).
这是一条大型动物：长225厘米（7英尺），腰围90厘米。它的嘴张开着，露出一排排锯齿状的牙齿。研究人员迅速工作，测量鲨鱼，记录性别，并采集血液和肌肉样本。然后，他们在其背鳍下方、穿过粗糙如砂纸的厚皮，固定了一个标签。
The mature male seems to watch them as they work. Then it is lowered back into the bay. With a powerful flick(轻甩，轻弹) of its tail, it disappears almost as quickly as it arrived.
这条成年雄性鲨鱼似乎在看着他们工作。然后它被放回海湾。它强有力的尾巴一甩，几乎像来时一样迅速地消失了。