Factors Influencing the Hooking Mortality of Walleyes Caught by Recreational Anglers on Mille Lacs, Minnesota

Abstract

Recent implementation of size-based regulations in recreational fisheries for walleye Sander vitreus have led to more released walleyes and presumably to more losses of released fish. We conducted this study to estimate hooking mortality in Mille Lacs, Minnesota, and to determine factors that influence the survival of released walleyes. Volunteers and Minnesota Department of Natural Resources employees sampled walleyes with common angling methods in 2003 and 2004 on Mille Lacs (n ¼ 1,246). Simple hooking mortality rates ranged from 0% (95% confidence interval ¼ 0-1.8%; n ¼ 204) in May, when lake water temperatures were less than 208C, to 12.2% (9.2-15.9%; n ¼ 392) in the July-August period, when lake water temperatures were at least 208C. We used logistic regression within generalized linear or additive models to determine influential variables. Hooking mortality was most associated with water temperature, bleeding, fish length, hook location, and fish floating upon release. Mortality increased as the water warmed above 188C and was higher for fish that bled at temperatures less than 248C but similar for both bleeding and nonbleeding fishes at temperatures of 248C or more. Fish hooked in the throat or stomach died at higher rates than fish hooked in the jaw, inner mouth, or gills and those that were externally foul-hooked, especially when they were smaller. Although fish of medium length (300-600 mm) were more likely to be deep hooked, they died less frequently than walleyes of other lengths. Cutting the line did not significantly improve survival in deeply hooked fish. Mortality was similar between live bait jigs and live bait regular hooks. Most observed hooking mortality was caused by damage to major internal organs. Hooking mortality is minimized when anglers fish in cool water, use active fishing methods, and catch medium-length walleyes.

Effects of Simulated Angler Capture and Live‐Release Tournaments on Walleye Survival

“…• C (Hoffman et al 1996;Graeb et al 2005;Reeves and Bruesewitz 2007;Schramm et al 2010). The rapid increase in mortality over this relatively narrow temperature range centered around 18…”

“…Several factors, including rough-water conditions (Goeman 1991;Suski et al 2005), capture depth (Schramm et al 2010;Talmage and Staples 2011), and hook wounding (Reeves and Bruesewitz 2007), have been suggested or found to influence health or mortality of angler-and tournament-caught Walleyes; however, water temperature appears to be the most pervasive factor. Mortality of angler-caught Walleyes increases with water temperature, but of potentially greater significance is the consistent finding that the probability of mortality increases sharply as water temperature increases from 14…”

Estimation of peacock bass (Cichla spp.) mortality rate during catch-release fishing employing different post-capture procedures

“…This is most likely due to the use of artificial baits, which are usually not swallowed deeply. Schill (1996), Schisler and Bergersen (1996), Dubois and Kuklinski (2004) and Reeves and Bruesewitz (2007) observed that the chances of fish swallowing the bait are greatly diminished when artificial baits are used as these are operated actively. Although mortality varies between species, higher mortality rates in general are associated with injury to internal organs and lesions with the presence of bleeding that could be associated with the use of natural bait (Muoneke and Childress, 1994;Bartholomew and Bohnsack, 2005;Broadhurst et al, 2005;Reeves and Bruesewitz, 2007;Alós et al, 2008;Alós, 2009).…”

“…There is some evidence that catch-and-release mortality rates are strongly influenced by the biological characteristics of the target species (Muoneke and Childress, 1994). However, certain other factors, such as the body part of the fish that was hooked (Pope et al, 2007;Alós et al, 2008), the type of bait (Reeves and Bruesewitz, 2007) and the fighting and handling time (Cooke and Suski, 2004) could also be determinants of mortality rate. Broadhurst et al (2005), studying the mortality rate of the main target species of Australian estuary sport fishing, reported mortality rates between 0 and 36.6% and found that the body part hooked and the time taken to release the fish were the main factors influencing mortality.…”

“…Broadhurst et al (2005), studying the mortality rate of the main target species of Australian estuary sport fishing, reported mortality rates between 0 and 36.6% and found that the body part hooked and the time taken to release the fish were the main factors influencing mortality. Reeves and Bruesewitz (2007) estimated the mortality rate for catch-and-release of Sander vitreus to be between 0% and 12.2% and found that it was related to water temperature, bleeding intensity, fish size and the body part hooked. Alós et al (2008) obtained similar values between 0% and 17.9% and found that hook shape and size were the key factors.…”