During the early stages when the aquaculture industry was rapidly expanding, mistakes were made and these were costly both in terms of direct losses and in respect of the industry’s image. High-density rearing led to outbreaks of infectious diseases that in some cases ① devastated not just the caged fish, but local wild fish populations too. The negative impact on local wildlife inhabiting areas ② close to the fish farms continues to be an ongoing public relations problem for the industry. Furthermore, a general lack of knowledge and insufficient care being taken when fish pens were initially constructed ③ meaning that pollution from excess feed and fish waste created huge barren underwater deserts. These were costly lessons to learn, but now stricter regulations are in place to ensure that fish pens are placed in sites ④ where there is good water flow to remove fish waste. This, in addition to other methods that decrease the overall amount of uneaten food, ⑤ has helped aquaculture to clean up its act.