December 17, 2019
By Savannah Fernholz, Andrea Sylvia, and Dr. Michael Weber
From the Field—Anglers often catch fish and observe what appear to be hook wounds on their mouths, presumably due to being previously caught. Questions concerning hook wounds include how long they last, how easily they’re detected, and if they can be used as an index of angling pressure? To answer these questions, we angled largemouth bass from a pond using a crankbait with two treble hooks and a soft-plastic worm with a single hook.* After capture, bass were held for six days to examine hook-wound detection and healing rates.
Hook wounds were detected in 100 percent of angled bass on the day of angling and were still observed on greater than 90 percent of bass seven days after capture. In May, 27 percent of hook wounds were healed within six days, but only 12 percent were healed within six days during July. No differences in hook-wound detection or healing rates were found for bass caught on crankbaits versus plastic worms.
Next, we visited 16 largemouth bass tournaments from April to October to determine the proportion of tournament fish displaying hook wounds. As many as 16 percent of tournament-caught fish did not have observable hook wounds. For those that did, hook wounds were most commonly on the roof of the mouth (52 percent), followed by the left jaw (26 percent) and right jaw (23 percent). Four percent of bass observed had broken jaws. Hook-wound detection did not vary among months and was not related to bass size.
Finally, we conducted monthly electrofishing to estimate the proportion of the total bass population with observable hook wounds. An average of 19 percent of bass captured with electrofishing displayed hook wounds, with the highest percentage of fish with wounds in August and the lowest percentage in April. The proportion of bass with hook wounds was positively related to the number of bass brought into tournaments.
Our study suggests hook wounds in largemouth bass are easily detected and last beyond one week post-angling. Thus, they have the possibility to be used as a short-term indicator of capture. Marks sustained during angling, such as hook wounds, may provide fishery managers with an easy and inexpensive way to estimate catch-and-release angling pressure on largemouth bass populations.
Savannah Fernholz, Andrea Sylvia, and Dr. Michael Weber
*Fernholz, S., A. Sylvia, and M. J. Weber. 2018. Hook wound longevity and use as an indicator of largemouth bass catch-and-release angling pressure. N. Am. J. Fish. Mgmt. 38:759-768.