Threatened fish are ‘uglier’, scientists discover

All fish are beautiful in their own way, from graceful angelfish and sleek tuna to the stoic grunts.

But some of the, perhaps, less obviously resplendent fish could face bigger problems than being overlooked by snorkellers.

A new study has found that endangered reef fish tended to score low on “aesthetic value”, meaning they could potentially be overlooked in conservation efforts if people focus on “prettier” species.

“Our study highlights likely important mismatches between potential public support for conservation and the species most in need of this support,” said study author Nicolas Mouquet, a community ecologist at the University of Montpellier, via a press release.

This is known to be the case when it comes to mammals, the research team noted, with species deemed more “beautiful” being more researched than other species.

However the new paper, published on Tuesday in the academic journal PLOS Biology, discovered that the “ugly fish” are generally more evolutionarily unique.

Researchers used a combination of computer modelling and public surveys to determine each fish’s “aesthetic value”.

Surveys asked participants to choose the more “beautiful” fish between two photos to determine what traits people found most pleasing, for instance, having multiple or brighter colours. Using those variables, the team built a computer model to rank fish by how pretty people found them.

Some groups, like the psychedelic butterflyfish and angelfish ranked consistently high in aesthetic value, while groups like the less colourful jacks and pompanos scored lower.

But the prettier fish were less unique in other ways. Uglier fish tended to be more distinct in both evolutionary history and their specific role in the ecosystem, the study found.

Yet when it came to conservation, fish species facing more threats tended to be the uglier ones.

The study found that species listed as “vulnerable”, “endangered” or “critically endangered” on the International Union for Conservation of Nature’s Red List had significantly lower aesthetic value score than fish listed as “least concern.”

Fish species without a Red List evaluation were right in the middle, by “beauty standards” - significantly prettier than the threatened group and significantly uglier than the “least concern” group.

Some of this might come down to how humans use these species. Fish used for commercial purposes had significantly lower aesthetic value than fish without commercial use or found only in subsistence fishing. Species with especially high commercial importance had even lower aesthetic scores.

The authors note that these results could lead to inequities between how much people might be willing to work on conservation for a species and how much that species might need conservation.