Effects of lure type, fish size and water temperature on hooking location and bleeding in northern pike (Esox lucius) angled in the Baltic Sea

• Different types of lures produce different probabilities of hooking location.
• Hooking in gills and aorta increased bleeding severity.
• Anglers can minimize injury in northern pike angling by the choice of appropriate gear.
• Hooking location is also affected by water temperature.
• Injury rates (as judged by bleeding) seem to be higher in larger pike.

In recreational fishing, catch and release (C&R), where fish are released alive after capture, is commonly adopted to minimize fishing mortality. Injuries from hooking and the mode of de-hooking can affect survival probability, and the choice of angling gear can affect injury severity. We show for C&R angling for northern pike (Esox lucius) in the Baltic Sea that hooking location and size of fish captured vary among lure types. Hooking in gills and aorta increased bleeding severity, which was generally expressed more strongly in larger pike. Our results supported the notion that anglers can minimize injury in northern pike angling by the choice of appropriate gear. In addition, our study is one of the first to show that hooking location is also affected by water temperature; low temperatures tended to result in deeper hooking. Despite this, water temperature did not affect level of bleeding in pike, and low water temperatures may be beneficial as they likely reduce the overall stress response in released pike.