Zebra mussels have to be power-hosed from the intake pipes of Great Lakes electric companies, and sea squirts form dense colonies that smother the scallops and clams of Georges Bank.

• 五大湖地区的电厂在抽取发电用水的时候要滤去沙筛贝，海鞘在乔治岸覆盖了这里原生的扇贝和蛤蜊。