[Can they see after release?]


Recent research shows that, not only can a large percentage of rockfishes survive once released to depth, but fish can recover from eye injuries (pop-eye) and regain their ability to see. This research showed the following:

1. When fish are recompressed, their eyes move back into normal position
2. The outside layer of the eye (cornea) is known to heal quickly in the marine environment
3. Rockfish showed little to no impairment to their vision after being recompressed
4. Rockfish forced down to depth likely have a high chance of being able to find food and avoid predators

rockfisheye

Close-up of rockfish eye in its natural position. Copyright Bonnie Rogers 2008.

fish1

Dorsal view of a rosy rockfish exhibiting exophthalmia (pop-eye) immediately following capture at sea. Copyright Bonnie Rogers 2009.

Eye exams on rockfish after catch-and-release shows they can still use their vision:

Fish naturally track moving objects with their eyes in order to prevent images from appearing blurred (humans naturally track moving object too). If a fish can distinguish the contrast between each black bar, then it will track the moving bars with the eyes. If the bars are too small for the fish to distinguish detail, then their eyes will not move at all. Rockfish with popeye were treated by recompression in chambers on land, removed from chambers and assessed for eye damage. These rockfish were able to track very narrow bars (less than 0.33 cm wide) indicating their ability to see this detail and resolve images.

Black and white moving bars that rockfish track with their eyes. Visual performance can be assessed by varying the width of the bars. Copyright Bonnie Rogers.