Assessing visual acuity in a pelagic marine predator, mahi-mahi (Coryphaena hippurus)

Larval mahi-mahi (Coryphaena hippurus) (7dph-10dph) were reared at the University of Miami- RSMAS where visual function was assessed using a flicker-fusion principle to monitor an optomotor response. Fish were placed in a glass cylinder with an opaque bottom, with a larger cylinder placed around the inner cylinder. The outer cylinder had alternating black and white stripes and driven by a 100 rpm motor, with a potentiometer assessing the speed of rotation. A GoPro (Hero 4+) was oriented above the chamber to view the fish’s behavior. Fish were preserved in Bouin’s solution for 24 hours, and transferred into a series of ethanol solution and placed in paraffin for histological work. Fish were sectioned by a microtome (5 µm sections) and a hematoxylin and eosin stain used. All slides were imaged on a Zeiss AX 10, and images analyzed using ImageJ software (v.1.43). This dataset includes videos of swimming mahi-mahi, microscope images of preserved and stained fish, and ocular measurements taken from images.