Its happened to everyone. You finally hook up with a fish after hours of flogging the water. Your heart starts racing. And then….SNAP!… you experience a sinking feeling as you realize your line snapped, or the knot you tied with tired eyes at 5 am let go.
But while many anglers feel bad about losing a fish, we also feel bad for the fish. The lure we were using is probably still stuck in that fish’s face! And while many humans seem to enjoy facial jewellery, fish have a different sense of style. So what happens to a fish when we break off? How long do they retain the lure, and does it have any negative effects on their health? These are the questions a group of scientists from Canada, USA and Germany tried to answer in a recent paper in Fisheries Research.
To perform this study, the researchers brought Northern pike into the lab and simulated the effects of a break off by attaching a lure to the fish’s mouth. Then, these fish were subject to a variety of testing to determine if fish with embedded lures behaved and responded differently to fish without embedded lures.
Over the period of 24 hours, 18% of the fish in the study were able to expel their lures, but this only occurred in fish that were hooked shallow (in the outside of the mouth) and did not occur if fish were hooked deeply.
For the rest of the fish, having an embedded lure did not seem to have a major influence on their physiology or behaviour. The hooked fish did not have different blood chemistry than fish without embedded lures, nor did they try to dislodge their lures by head shaking or other erratic behaviour. However, the hooked fish did have a higher ‘operculum pumping rate’ than fish without retained lures, suggesting that embedded lures might affect their respiration and make them work harder to recover from exercise.
The authors note that their study was relatively ‘short term’ and so it is still possible that break-offs could have a negative long term effect on pike. For example, lure retention might make it harder for fish to feed. As a result, the authors still caution that avoiding break offs (by using proper gear for the species you are targeting, and checking that gear over carefully) is still beneficial for the welfare of fish. And using barbless hooks is probably still helpful to minimize lure retention if you do break off. Regardless of the outcome for fish, we should all aim to land as many fish as we hook, both for our own pride, but also for the fish!
Citation: Pullen CE et al. 2017 Consequences of oral lure retention on the physiology and behaviour of adult northern pike (Esox lucius L.). Fisheries Research, 186:601-611
Find the article here