Electroreception in the euryhaline stingray, Dasyatis sabina

Area of Science:

• Marine biology
• Sensory physiology
• Elasmobranch biology

Background:

• The Atlantic stingray (Dasyatis sabina) is a euryhaline elasmobranch found in diverse salinity environments.
• Understanding sensory adaptations is key to comprehending species' ecological niches and survival strategies.

Purpose of the Study:

• To quantify the electrosensitivity of Atlantic stingrays (Dasyatis sabina) across a spectrum of salinities.
• To compare electrosensory performance between freshwater and brackish/saltwater populations.

Main Methods:

• Behavioral responses to simulated prey electric stimuli were measured in freshwater (0 p.p.t.), brackish (15 p.p.t.), and saltwater (35 p.p.t.).
• Electric field thresholds and orientation distances were quantified for stingrays from both freshwater and estuarine populations.

Main Results:

• Electrosensitivity was significantly reduced in freshwater, requiring 200-300x greater electric fields to elicit feeding responses.
• Maximum prey detection range decreased by 35.2% in freshwater compared to brackish and saltwater conditions.
• Stingrays did not show enhanced freshwater electrosensitivity or reduced sensitivity in higher salinities; responses were salinity-dependent, not population-specific.

Conclusions:

• The reduced electrosensitivity in freshwater is linked to water resistivity and ampullary canal function.
• The Atlantic stingray's electrosensory system exhibits remarkable plasticity, enabling function across a wide range of salinities.
• This sensory adaptability highlights its evolutionary significance for survival in variable estuarine and marine environments.