Glowing Sharks Have Unusual Eyes


There are species of shark that are bioluminescent and have evolved ocular structures designed to detect faint light patterns in the deep ocean produced by other bioluminescent sharks that live at depths from 600 to 3,000 feet in the mesopelagic zone where very little sunlight reaches.

These eyes as expected, have visual adaptations optimized for this environment.  Julien Claes, the lead authors of a new study notes that “There are about 50 different shark species that are able to produce light”.  Given that there are 50 separate bioluminescent species of shark, one might expect some visual system specializations and indeed there are.  Everything from higher rod densities to descriptions of bioluminescent specializations used for communication and specialized transparencies in the upper socket of the eye to help adjust illumination. Continue reading “Glowing Sharks Have Unusual Eyes”

Interesting papers: Light and vision in the deep-sea benthos

Vision in fishes and crustaceans is a fascinating and understudied area.  In past decades, there were far more studies on the visual systems of sea-dwelling creatures, but with the push towards applied or translational research, the number of reports in these species have dropped off, much to our detriment as one never knows where the applications of basic research will pay off.

At the same time, the whole study of bioluminescence and vision is an interesting examination of how organisms use bioluminescence for mating, warning or aposematismcrypsis or counter-illumination and predation.  It is explicitly a visual phenomenon and as such, has informed a variety of investigations into biomedical, commercial and military applications. Continue reading “Interesting papers: Light and vision in the deep-sea benthos”