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Visual acuity of snapper Pagrus auratus : effect of size and spectral composition
Author(s) -
Robinson E.,
Jerrett A. R.,
Black S. E.,
Davison W.
Publication year - 2011
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2011.03130.x
Subject(s) - biology , pagrus , pagrus major , composition (language) , sparidae , spectral composition , fishery , zoology , fish <actinopterygii> , optics , physics , linguistics , philosophy
Visual acuity of the commercially important sparid Pagrus auratus was tested using the optomotor response. Juvenile fish were categorized by size as group 1 (50 g), group 2 (100 g), group 3 (150 g), group 4 (300 g), group 5 (500 g) and group 6 (800 g). Group 3 fish demonstrated excellent visual acuity (minimum separable angle, M SA , 1°), which was improved compared with the smaller fish groups (groups 1 and 2, M SA , 2°). In the larger fish groups, however, a reduction in visual acuity was observed (groups 4, 5 and 6 M SA , 4°). Group 2 (100 g) fish displayed positive optomotor responses in long wavelength light (red) but reduced responses in short wavelengths (blue). Red light sensitivity is beneficial for the estuarine lifestyle of these fish, where light is predominantly at long wavelengths. In contrast, group 6 (800 g) fish displayed improved acuity in blue and green light and reduced acuity in red light. Fish of this size move away from the estuary to open oceans, where light is predominantly in the shorter wavelengths (blue‐green). These results support the sensitivity hypothesis for the relationship between fish visual systems and the light environment they inhabit.