Cooke Aquaculture, the company that owns the floating mesh cages that broke in Washington, blames the failure on unusually high tides stressing older equipment. But open-net pens have long been maligned by environmentalists. Critics charge that using open-net pens to raise fish increases the risk of diseases and non-native species mingling with wild populations. Industry representatives say the pens are safe—a stance supported by research. But there are known problems, such as outbreaks of pathogens like sea lice.