I found this on page 127 of "Bluegills, Biology and Behavior", by Stephen Spotte.
This is from a study conducted during the summer, which produced results showing that the half-life of stomach fullness decreased linearly over a given temperature range...which in this case was 10-25 degrees Celsius (50F-77F).
An equation was used to demonstrate this regression:
y = 23.1-0.901x
Where y is the half-life of stomach fullness ( brought upon by digestion), and x is the water temperature in Celsius.
If we plug in their numbers, we see that at 25*C, (77*F), the elapsed time needed was only .87 hrs. However, at the other end of the scale, 10*C (50*F), the time needed increased to just over 14 hrs.
The regression is reportedly linear throughout the temps recorded during the study, but I haven't found any further information to indicate if it remains so as water temps continue to decline. However I am reasonably confident that at minimum, the time needed for digestion will continue to increase as water temps fall. If we allow for a temp. of 38*F, the time increases to over 20 hours, IF the rate continues to be linear.
This shows that time required for digestion is dependent upon temperature....the colder the water, the longer the time needed. What bearing, if any, the addition of pelleted, processed feed might have on the digestion rate is unclear to me, as are any possible ill effects that might be suffered by the fish as a result of undigested feed remaining in the stomach, vs. natural forage.
The author referenced a handful of studies in this regard, some of which are 40+ years old and may not reflect current thinking and understanding. Nevertheless, I am trying to locate these pieces to order to try and further my understanding regarding feeding processed pellets during the winter months.
Last edited by Bill Cody; 02/23/15 11:00 AM. Reason: aqded F temp range
