'Ugly' fish need conservation most

Never judge a book by its cover — it's a principle we would like others to apply to us. But we do often judge others by their looks and a new study has found that our inclination to judge based on appearances also extends to the oceans.

The species of reef fishes that people find least beautiful tend not to be prioritized for conservation support, says the study published in the journal PLOS Biology. But it's "ugly" fish and the ecosystems they support that need conservation most.

Researchers at the University of Montpellier in France say they found that species ranked as more attractive tend to be less distinctive in terms of their ecological traits and evolutionary history.

How they ranked beautiful and 'ugly' fish

The researchers used an online survey to ask 13,000 members of the public to rate the aesthetic attractiveness of more than 480 photographs of ray-finned reef fishes — fishes being different species of fish.

Then they used the information from the survey to train an artificial intelligence technology, known as a convolutional neural network, to respond to yet more images in a similar way to the participants of the survey.

Once trained, the AI generated predictions — or aesthetic assessments — for an additional 4,400 photographs, featuring 2,417 of the most common reef fish species.

Why 'ugly' fish need conservation

When the public's ratings were combined with the AI's predictions, the scientists found that bright colorful fish species with rounder bodies tended to be rated as the most beautiful.

That does not bode well for "ugly" fish species or support from the public for conservation, say the researchers.

The study says that the ecological and evolutionary distinctiveness of unattractive fishes makes them important for the functioning of an entire reef and their loss — through a lack of conservation, for instance — could affect these ecosystems high in biodiversity.

Species listed on a so-called Red List as threatened, or species whose conservation status has yet to be evaluated, had a lower aesthetic value on average than species categorized as of "least concern," say the researchers.

The Red List is maintained by the International Union for Conservation of Nature.

What humans find 'beautiful'

Nicolas Mouquet, an ecologist and lead author on the study, told DW that neuroaesthetic studies had shown that certain images tend to be judged as beautiful more than others.

For instance, when elements of an image can be removed from their background or visual features of a subject can be grouped into recognizable objects, that can trigger a sense of aesthetic pleasure in our minds.  

The study authors say that our preferences for shape and color, including when we look at fish, may be due to the way the human brain processes colors and patterns.

But there is a mismatch between our sense of aesthetic value, a species' ecological function and its vulnerability to extinction. That, according to the study, means that when it comes to conservation, less attractive species may miss out on public support.

Avoid bias with better communication

Human bias for aesthetically pleasing groups of animals is common.

"Our study highlights important mismatches between potential public support for conservation and the species most in need of this support," said Mouquet, adding that unattractive species also had greater commercial interest.

Mouquet said he hoped researchers would collectively minimize the impact of human perception biases through better communication with the public, policymakers and conservation groups.

Edited by: Zulfikar Abbany