Visual acuity in pelagic fishes and mollusks.

Published

Journal Article

In the sea, visual scenes change dramatically with depth. At shallow and moderate depths (<1,000 m), there is enough light for animals to see the surfaces and shapes of prey, predators, and conspecifics. This changes below 1,000 m, where no downwelling daylight remains and the only source of light is bioluminescence. These different visual scenes require different visual adaptations and eye morphologies. In this study we investigate how the optical characteristics of animal lenses correlate with depth and ecology. We measured the radius, focal length, and optical quality of the lenses of pelagic fishes, cephalopods, and a gastropod using a custom-built apparatus. The hatchetfishes (Argyropelecus aculeatus and Sternoptyx diaphana) and the barrel-eye (Opisthoproctus soleatus) were found to have the best lenses, which may allow them to break the counterillumination camouflage of their prey. The heteropod lens had unidirectional aberrations that matched its ribbon-shaped retina. We also found that lens angular resolution increased with depth. Due to a similar trend in the angular separation between adjacent ganglion cells in the retinas of fishes, the perceived visual contrast at the retinal cutoff frequency was constant with depth. The increase in acuity with depth allows the predators to focus all the available light bioluminescent prey animals emit and detect their next meal.

Full Text

Duke Authors

Cited Authors

  • Gagnon, YL; Sutton, TT; Johnsen, S

Published Date

  • November 2013

Published In

Volume / Issue

  • 92 /

Start / End Page

  • 1 - 9

PubMed ID

  • 23998988

Pubmed Central ID

  • 23998988

Electronic International Standard Serial Number (EISSN)

  • 1878-5646

International Standard Serial Number (ISSN)

  • 0042-6989

Digital Object Identifier (DOI)

  • 10.1016/j.visres.2013.08.007

Language

  • eng