Jaw-hooked red snapper and deep-hooked red snapper respond differently after release.
Research Need
Red snapper are one of the most sought-after reef fish in the South Atlantic, but many are released after being caught because of size or season limits. Unfortunately, not all released fish survive.
When fish are pulled up quickly from deep water, the rapid water pressure change can cause barotrauma — swelling from expanding gases inside the body. In addition, the damage from a deep hook can decrease the chances of survival even more.
Understanding how these factors affect survival can help guide fishing practices and management.
What Did They Study?
Researchers with NC State University, the National Oceanic and Atmospheric Administration (NOAA), and other organizations studied how hook location affects red snapper survival after release. In 2019 and 2023, they tagged 79 fish off Raleigh Bay, North Carolina, with small sound-emitting acoustic devices and used a network of underwater receivers to track movement.
To catch red snapper from about 125 feet (38 meters) deep, the research team used hook-and-line gear with two types of hooks: J-hooks (which are more likely to cause deep hooking) and circle hooks. They then grouped the fish into two categories: jaw-hooked fish (hooked in the mouth) or deep-hooked fish (hooked in the gills, throat, or stomach).
The team released all fish back to depth using descender devices to relieve barotrauma. The team tracked how long each fish survived and what happened afterward, including whether it stayed in the area, lost its tag, or died soon after release.
What Did They Find?
Hooking location made a big difference. After researchers returned jaw-hooked fish with a descender device, the fish had a very high survival rate, with only 6% dying. Most were still alive at the end of the study.
In contrast, deep-hooked fish had a poor survival rate, with roughly 88% dying within one day of release. Even though researchers returned the deep-hooked fish to depth with a descender device, none of the deep-hooked fish were still alive at the end of the monitoring period.
What Else Did They Find?
Other factors such as fish size, water temperature, or year of capture didn’t have a noticeable effect on survival.
So What?
The study confirmed that acoustic tagging, which monitors fish movements and behaviors in aquatic environments, is a reliable way to determine whether released fish survive.
These findings strongly suggest that using circle hooks — which tend to catch fish in the mouth — can make a big difference for red snapper survival. Deep hooking, which occurs more often with J-hooks, leads to high discard mortality even when fish are carefully released with a descending device.
Therefore, using circle hooks and recompression tools whenever possible can help reduce fish deaths, support stock recovery, and keep the red snapper fishery sustainable for the future.
Reading
Reading
Rudershausen, P. J., Runde, B. J., Tharp, R. M., Merrell, J. H., Bacheler, N. M., Patterson III, W. F., & Buckel, J. A. (2025). Discard mortality rates of Red Snapper after barotrauma and hook trauma: Insights from using acoustic telemetry in the U.S. South Atlantic. North American Journal of Fisheries Management, 45(2), 270–282. https://doi.org/10.1093/najfmt/vqaf012
This study was partially supported by funding from the National Marine Fisheries Service and South Carolina Sea Grant through the South Atlantic Red Snapper Research Program.
Lead photo: Anglers identify signs of barotrauma on a red snapper. Credit: Return ‘Em Right.
The text from Hook, Line & Science is available to reprint and republish at no cost, but only in its entirety and with this attribution: Hook, Line & Science, courtesy of Scott Baker and Sara Mirabilio, North Carolina Sea Grant.
