Comparative visual function in four piscivorous fishes inhabiting Chesapeake Bay

Area of Science:

• Aquatic ecology
• Sensory biology
• Ichthyology

Background:

• Visual performance in coastal/estuarine waters is challenging due to tradeoffs between light sensitivity and resolution.
• The visual systems of coastal piscivores are understudied despite variations in their ecology.

Purpose of the Study:

• To characterize the luminous, temporal, and spectral sensitivities of four common coastal piscivores: striped bass, bluefish, summer flounder, and cobia.
• To compare visual system adaptations in relation to ecomorphology and microhabitat use.

Main Methods:

• Electroretinography was used to measure visual system properties.
• Flicker fusion frequency experiments assessed temporal resolution at maximum light intensities.

Main Results:

• Benthic summer flounder demonstrated higher luminous sensitivity and a broader dynamic range than pelagic species.
• Pelagic species exhibited less sensitivity but greater day-night visual differences, aligning with their habitats.
• Spectral sensitivities generally ranged from 400-610 nm, with striped bass and bluefish showing day-night variations.

Conclusions:

• Pelagic piscivores are adapted to bright conditions, which may conflict with degraded coastal water quality.
• Anthropogenic impacts on water quality may hinder visual foraging, alter prey selection, and restructure coastal ecosystems.