The Challenge Of Measuring Individual Fish Welfare
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Animal welfare is typically considered an individual characteristic. The authors of this paper define welfare as an animal’s emotional experiences as a result of their living conditions, ranging from negative to positive. It is easier to provide good welfare to a smaller number of animals. It becomes harder for fishes in the aquaculture industry, who are densely packed into farms. In some cases, fish farmers handle hundreds of different species with different needs, meaning it’s close to impossible to treat fishes as individuals.
This paper reviews current literature showing that fishes and their welfare should be treated at the individual level and examines the way fish welfare is assessed. The authors then compare this with welfare assessments of land animals and recommend ways to improve individual fish welfare.
The way the fish farming industry operates means that the amount of personalized care that can be provided to individual fishes is low. Most fish farming reports discuss fishes in tons rather than as individuals, but the estimated number of farmed fishes in 2017 was between 51-167 billion. According to the authors, the task of addressing individual welfare is even more challenging since individual fishes differ even within one species.
Research shows fish personalities vary, which impacts how they react to their environment and therefore their welfare. For example, less aggressive salmon fishes tend to get less food and do not grow as much as their more aggressive counterparts. The evidence suggests that fishes are capable of social cognition, spatial learning, and other types of cognition seen in mammals. They can also feel emotions such as fear and pain.
The authors point out that fishes’ unique capabilities result in individual preferences, which may affect what farmed fishes need to thrive in their environment. However, most research on fish preferences looks at preferences at the species level. Furthermore, the vast majority of farmed species has not been studied.
Historically, “good” fish welfare has mainly considered physical health and growth indicators (especially since the aquaculture industry is concerned with growth and production). With fish behavior now recognized as an important component of welfare, some scholars are calling for more fish behavioral research. However, there is still no measurement of welfare at the level of the individual fish.
Group-level assessments are common for measuring fish welfare. In these assessments, inspectors sample a small percentage of fishes, measure their welfare, and then extrapolate the percentage of fishes with poor welfare to give an average welfare measurement of the remaining fishes. In some cases, 10% of fishes experiencing poor welfare are acceptable. However, the authors point out the flaws in this system, including that it allows fishes to experience bad welfare as long as it doesn’t exceed the 10% maximum. It also assumes that the small percentage of fishes is representative of the remaining group.
There are some technological tools that could help farmers achieve individual welfare monitoring, including underwater cameras, computer vision methods, and acoustic devices. According to the authors, zoos have implemented individual-level assessments, and some zoos are also looking at new technologies to help address welfare (e.g., GPS systems, accelerometers). The authors note that some of these systems may be adaptable to the aquaculture industry.
Implementing individual welfare for billions of fishes is a big challenge. Observing the natural behavior of fishes in the wild would provide useful information, but this presents its own challenges. The literature around fish welfare is growing, and the authors believe more emphasis should be put on learning about what individual fishes need to thrive. Researchers should also identify the most harmful captive settings and small improvements that can be made on farms to enhance individual welfare. Animal advocates can support this research by calling for funding and resources to be invested in this cause.
https://www.mdpi.com/2076-2615/12/19/2592