Senior Project Advisor

Shull, David, 1965-

Document Type


Publication Date

Spring 2020


Cownose rays, Rhinoptera bonasus, intertidal, Delaware Bay, Rutgers University


Environmental, temporal and life history factors are known to influence and cause variation in cownose ray Rhinoptera bonasus movements, but their use of the intertidal zone has not been fully studied. Cownose rays eat ribbed mussels, an obligate intertidal species; thus their intertidal visitation may be important. We investigated cownose ray movement, from fixed Dual Frequency Identification Sonar (DIDSON) at the Rutgers Cape Shore Laboratory mudflats, relative to water temperature, diel pattern, diurnal conditions, tidal phase, current speed, and heading. Behavioral Observation Research Interactive Software (BORIS) was used to digitally record cownose ray appearance in 170 randomly selected ten-minute sonar videos. Cownose rays have a threshold temperature at 17 degrees celsius, above which they occupy the intertidal zone. A diurnal-tidal phase co-interaction was observed, with a high abundance of daytime cownose rays during flood tide and night-time rays during ebb tide. Additional behaviors of cownose rays include feeding, schooling, and stationary behavior. These interactions require further research to evaluate frequency and influence. Understanding cownose ray use of intertidal habitats is important due to the habitat's ecological link between land and sea as it faces changes from sea level rise, erosion armoring and aquaculture development.


Environmental Sciences

Subjects - Topical (LCSH)

Rays (Fishes)--Behavior--Delaware Bay (Del. and N.J.); Rays (Fishes)_Migration--Delaware Bay (Del. and N.J.); Intertidal zonation--Delaware Bay (Del. and N.J.)

Geographic Coverage

Delaware Bay (Del. and N.J.)


student projects; term papers




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