And bumping into the sharks' flanks helps the jacks to rid themselves of parasites and dead skin.往鲨鱼的侧面撞击有助于六带鲹清除身上的寄生虫和死皮

bump into:猛撞，撞击

He wasn't looking and ran bump into a tree.

他没看好路猛然撞在一棵树上。

rid of:摆脱

He wasn't rid of the mental burden.

他摆脱不了精神负担。

Let's get rid of this mouldy old furniture.

咱们把这件老掉牙的旧家具扔掉吧。

And soon swarms of jacks pursue the sharks.很快便有成群的六带鲹前去追逐鲨鱼

swarms of:一群群； 一大堆

There were swarms of mosquitoes around here.

这儿蚊虫成群。

She left amid a swarm of photographers.

她离开时一群摄影记者围着她。

Each tentacle is armed with paralysing stings that can kill a fish.每根触须都长了具有麻痹作用的棘刺可能让鱼儿一命呜呼

arm with: 武装(用 ... 装备)

We set out armed with warm clothes.

我们动身时带了御寒的衣服。

Our fighter planes are all armed with cannon.

我们的战斗机都装备了机关炮。