Biofluorescence Illuminates the Underwater World: Fish Use Light for Communication and More

Marine researchers have recently uncovered new details about the prevalence and function of biofluorescence in fish, revealing its potential roles in communication, camouflage, and even biomedical applications. Two studies spearheaded by the American Museum of Natural History shed light on the evolutionary history and diversity of this fascinating phenomenon, demonstrating that it has evolved independently over 100 times in marine teleosts, dating back at least 112 million years [1].

The Widespread Nature of Fish Biofluorescence

Biofluorescence, the process by which organisms absorb high-energy light and re-emit it at lower energy wavelengths, is far more common than previously thought. Emily Carr, a Ph.D. student at the American Museum of Natural History, notes that while biofluorescence has been observed in various marine animals, its prevalence among fish is notably noteworthy. A study published in *Nature Communications* examined all known biofluorescent teleosts,identifying 459 species,including 48 previously unknown to exhibit this trait [1].

Did You No? Biofluorescence differs from bioluminescence. Bioluminescence is the production and emission of light by a living organism,while biofluorescence requires an external light source.

Evolutionary Insights

The research indicates that biofluorescence evolved independently over 100 times in marine teleosts, with the earliest instance occurring in eels approximately 112 million years ago. Moreover, fish species inhabiting coral reefs exhibit a significantly higher rate of biofluorescence evolution compared to non-reef species. This suggests that the emergence of modern coral reefs may have facilitated the diversification of fluorescence in reef-associated teleost fishes [2].

The rise in fluorescent species coincides with the rise of modern coral-dominated reefs and the rapid colonization of reefs by fishes, which occurred following a critically important loss of coral diversity in the end-Cretaceous extinction.

The Role of Coral reefs

The close association between coral reefs and biofluorescent fish is highlighted by the fact that the majority of the 459 known biofluorescent teleosts are found in coral reef environments. This correlation suggests that the unique ecological conditions of coral reefs may promote the evolution and diversification of biofluorescence [1].

Unveiling the Diversity of Colors

A second study, published in *PLoS ONE*, utilized specialized photography to analyze the wavelengths of light emitted by fish specimens collected from various locations, including the Solomon Islands, Greenland, and Thailand. the findings revealed a far greater diversity in colors emitted by teleosts than previously recognized, with some families exhibiting at least six distinct fluorescent emission peaks [2].

Pro Tip: When observing biofluorescence, consider the light source. Different light sources can affect the appearance and intensity of the fluorescence.

Potential Applications in Biomedicine

The diverse wavelengths of fluorescent emissions observed in these studies have potential implications for identifying novel fluorescent molecules. These molecules are routinely used in biomedical applications, including fluorescence-guided disease diagnosis and therapy. The revelation of new fluorescent proteins could significantly advance these fields [1].

Biofluorescence in Marine Fishes: Key Data

What other marine mysteries might biofluorescence help us unlock? How can we better protect the coral reef ecosystems that foster this phenomenon?

Disclaimer: This article provides general information about biofluorescence in marine fish and shoudl not be considered as professional scientific advice.

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