Examining the Severity of Roof‐Hooking Injuries in Dolphinfish: a Comparison between Computed Tomography and Gross Necropsy North American Journal of Fisheries Management

We describe hook trauma to the roof of the mouth in Dolphinfish Coryphaena hippurus and compare computed tomography (CT) scanning to gross necropsy (GN) as a technique for diagnosing hooking injury in fish. Forty‐two Dolphinfish carcasses spanning a range of hook injuries were collected and CT scanned, and 33 of those carcasses were evaluated using GN. Specimens were hooked either in the roof of the mouth, the eye via the roof or upper jaw, or the jaw (control group). In 75% of roof‐hooked individuals, GN revealed nondisplaced to comminuted fractures of the bones of the suspensorium, hematomas in and laceration of the extraocular muscles, and/or damage to the optic nerve. These injuries have the potential to compromise vision and therefore decrease postrelease survival rates of obligate sight‐feeding species such as the Dolphinfish. We evaluated the effectiveness of CT scanning to diagnose injury and found that CT could efficiently and accurately identify fractures and some soft‐tissue damage, but some injuries found in GN (e.g., optic nerve damage) were not observed on CT scans. Based on our findings, it is likely that mortality is greater in Dolphinfish when hooked in the roof of the mouth than when hooked in the jaw. This study demonstrates a novel technique that was effective at diagnosing hooking injuries associated with the roof of the mouth. Grant no. NA15NMF4270346