Here’s the Temperature section from the Casselman article I posted. Take a minute to read it.
“Temperature
Evidence suggests that catch-and-release mortality is directly related to water
temperature, with mortality increasing at extreme temperatures. In a seasonal comparison of
hooking mortality of bluegill, Muoneke (1992b) found that mortality was greater in the summer
when water temperatures were highest. However, this study did not account for other variables,
such as differences in feeding rate or reproductive status, which may have increased mortality
during the summer. Similarly, mortality in cutthroat trout has been shown to increase from 0 to
8.6% as water temperature increased from 8°C to 16°C (Dotson, 1982). In a meta-analysis of
black bass mortality associated with tournaments, a strong relationship was found between water
temperature and both pre-release and post-release mortality (Wilde, 1998). Research from
walleye tournaments indicates that mortality increases with water temperature and suggests that
tournaments should be limited to the spring and fall (O’Neil and Pattenden, 1992), or when water
temperatures are cooler than 15.6°C (60°F) (Boland, 1994). Wilkie et al. (1997) examined the
post-exercise physiology of Atlantic salmon at 12°, 18° and 23°C, and found that physiological
recovery was slowest at 12°C, however, there was significant mortality at 23°C. This result
suggests that warmer temperatures facilitate recovery but that extremely high temperature
increases mortality.
Nuhfer and Alexander (1992) found that mortality increased with water temperature in
brook trout that were bleeding from the gills or throat area as a result of hooking. Mortality has
also been found to increase with water temperature in smallmouth bass (Cooke and Hogle,
2000), largemouth bass (Gustaveson et al., 1991; Meals and Miranda, 1994) and striped bass
(Nelson, 1998). Interestingly, Bettoli and Osborne (1998) found that catch-and-release mortality
in striped bass was linearly related to air temperature but not water temperature, suggesting the
temperature during air exposure may be more important in determining survival than actual
water temperature. These studies demonstrate that catch-and-release mortality increases with
temperature and special care should be taken with fishing during extremely warm weather.
There has been a similar concern with releasing fish that have been angled during icefishing
and exposed to cold temperatures. It has been suggested that eyes and gills can be
damaged from freezing on extremely cold days. However, studies examining catch-and-release
survival of walleye during ice-fishing found no evidence of damage or mortality caused by
exposure to cold temperatures (Ellis, 2000). Thus, while brief exposure of fish to cold
temperatures may not cause mortality or damage, it is best minimize the time that fish are kept
out of the water when ice-fishing.”
See all those names and dates in parentheses? Those are references to actual data from actual studies done on actual fish. These are studies done by educated and trained scientists/biologists. These guys know a thing or two.
No, they didn’t actually tag a muskie and watch it die after being caught in warm water, but with a little open mindedness and some scientific thinking one can easily make the obvious connection.