Abstract
Both residual downwelling sunlight and bioluminescence, which are the two main sources of illumination available in the deep sea, have limited wavebands concentrated around 450-500 nm. Consequently, the wavelengths of maximum absorption (lambdamax) of the vast majority of deep-sea fish visual pigments also cluster in this part of the spectrum. Three genera of deep-sea loose-jawed dragonfish (Aristostomias, Pachystomias and Malacosteus), however, in addition to the blue bioluminescence typical of most deep-sea animals, also produce far-red light (maximum emission >700 nm) from suborbital photophores. All three genera are sensitive in this part of the spectrum, to which all other animals of the deep sea are blind, potentially affording them a private waveband for illuminating prey and for interspecific communication that is immune from detection by predators and prey. Aristostomias and Pachystomias enhance their long-wave visual sensitivity by the possession of at least three visual pigments that are long-wave shifted (lambdamax values ca. 515, 550 and 590 nm) compared with those of other deep-sea fishes. Malacosteus, on the other hand, although it does possess two of these red-shifted pigments (lambdamax values ca. 520 and 540 nm), lacks the most long-wave-sensitive pigments found in the other two genera. However, it further enhances its long-wave sensitivity with a chlorophyll-derived photosensitizer within its outer segments. The fluorescence emission and excitation spectra of this pigment are very similar to spectra obtained from mesopelagic copepods, which are an important component of diet of Malacosteus, suggesting a dietary origin for this pigment.
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Selected References
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- Denton E. J., Gilpin-Brown J. B., Wright P. G. On the 'filters' in the photophores of mesopelagic fish and on a fish emitting red light and especially sensitive to red light. J Physiol. 1970 Jun;208(2):72P–73P. [PubMed] [Google Scholar]
- Douglas R. H., Partridge J. C., Dulai K. S., Hunt D. M., Mullineaux C. W., Hynninen P. H. Enhanced retinal longwave sensitivity using a chlorophyll-derived photosensitiser in Malacosteus niger, a deep-sea dragon fish with far red bioluminescence. Vision Res. 1999 Aug;39(17):2817–2832. doi: 10.1016/s0042-6989(98)00332-0. [DOI] [PubMed] [Google Scholar]
- Douglas R. H., Partridge J. C., Marshall N. J. The eyes of deep-sea fish. I: Lens pigmentation, tapeta and visual pigments. Prog Retin Eye Res. 1998 Oct;17(4):597–636. doi: 10.1016/s1350-9462(98)00002-0. [DOI] [PubMed] [Google Scholar]
- Partridge J. C., Shand J., Archer S. N., Lythgoe J. N., van Groningen-Luyben W. A. Interspecific variation in the visual pigments of deep-sea fishes. J Comp Physiol A. 1989 Jan;164(4):513–529. doi: 10.1007/BF00610445. [DOI] [PubMed] [Google Scholar]
- Wagner H. J., Fröhlich E., Negishi K., Collin S. P. The eyes of deep-sea fish. II. Functional morphology of the retina. Prog Retin Eye Res. 1998 Oct;17(4):637–685. doi: 10.1016/s1350-9462(98)00003-2. [DOI] [PubMed] [Google Scholar]
- Widder E. A., Latz M. I., Herring P. J., Case J. F. Far red bioluminescence from two deep-sea fishes. Science. 1984 Aug 3;225(4661):512–514. doi: 10.1126/science.225.4661.512. [DOI] [PubMed] [Google Scholar]