Cleaner fish: A neglected issue within a neglected issue

Abstract

Each year millions of cleaner fish are stocked in salmon farms to “clean” salmon of sea lice, leading to their suffering and death, without necessarily lowering the rates of sea lice. This post gives an overview of the issue in four parts: the neglectedness of fish welfare in general, the number of cleaner fish stocked in salmon farms and the reasons for this, the welfare issues cleaner fish endure, and suggestions for what can be done about this problem. Most data is from Norway, the world’s largest producer of farmed salmon. Key takeaways: Despite strong evidence for fishes’ capacity to suffer, their welfare has long been neglected by both fishing industries and animal advocates.Sea lice is a big problem in salmonid farming, and after lice have become increasingly resistant to chemical treatment, other delousing methods have been employed, the least harmful to salmon of these being cleaner fish.Cleaner fish are not adapted to the environment that salmon live in and face disease and high mortality rates. There are also many problems with the way they are treated by the Norwegian cleaner fish and salmon industries.The evidence of cleaner fishes’ effectiveness at delousing salmon is sparse, and it is argued that it is not adequate to justify the widespread use of cleaner fish.Suggested interventions are corporate outreach to improve cleaner fish welfare, or to end the use of cleaner fish entirely, as well as working on shifting the public opinions about fishes’ welfare and moral value.