Relative Hooking Mortality among Walleyes Caught on Barbed and Barbless Octopus Hooks and Barbed Jigs

Abstract

Anglers sometimes use alternatives or modifications to J-shaped hooks to reduce hooking mortality in fish that are caught with live baits and then released. One such modification, the removal of barbs, has been evaluated for several fish species but has shown little promise for reducing hooking mortality; however, barbless hooks have not been evaluated for walleye Sander vitreus. We evaluated relative mortality for walleyes (228–419 mm total length) that were caught by means of bobber fishing with leeches on barbed (n = 179 fish) or barbless (n = 209) live-bait octopus hooks or on barbed jigs (n = 193); after capture, the fish were held for 120 h in net pens. Holding mortality was a function of water temperature, cage density, bleeding level, and hook location; fish length and angler handling time did not significantly affect mortality. We combined hook location and bleeding level to create a single variable, hooking damage, which was used to replace the two variables in the initial model. This second model was similar to the first, indicating that hooking damage was correlated with mortality when controlling for the effects of water temperature and cage density. We also determined that hooking damage was correlated with hook type. For the 228–419-mm walleyes in our study, barbed jigs caused less damage than live-bait hooks and damage levels were similar between barbed and barbless live-bait hooks. Given specified levels of hooking damage, holding mortality was independent of hook type. We hypothesize that the fish in this study were too small to swallow the jigs well and thus were hooked less critically and bled less than fish that were caught with live-bait hooks. This study illustrates how gear type can affect hooking mortality based on the amount of damage caused when the fish is caught and adds to the body of literature indicating that the removal of barbs from hooks does not increase fish survival.

Received March 15, 2010; accepted November 17, 2010

ACKNOWLEDGMENTS

We thank the private citizens and Minnesota Department of Natural Resources employees who volunteered for fieldwork; Melissa Drake and five anonymous reviewers for their constructive comments; and the Minnesota Legislature for funding.

Notes

^aNone or light = spots of blood; moderate or heavy = lines of blood.

^bShallow = outside or inside of mouth but not past esophageal opening; deep = imbedded in esophagus or stomach.

^cWater temperature range was 19.4–26.7°C.

^dAngler handling time was recorded only for a subset of fish.