I found two large tilapia dead this afternoon.(NE Texas)
I’m surprised I haven’t seen more.
Pretty fish. Love the golden hues. What county are you in Tbar?.
The paper below recorded Cold Degree Days and associated mortality for Moz TP and Blue TP. This is similar to degree days we often see in agriculture but instead of temps above freezing they measure the degrees below 16C (~62F). The experiments were in Israel and the original MozTP were from South Africa. MozTP from southern part of their range happen to be only modestly less temperature tolerant than blues. Anyways, and this is confirmed by other experiments, there tends to be mortality over a couple of weeks. Starts off gradually and picks up pace over 3-4 days and then decreases until all are dead. In the second experiment, they reduced temperature by .45 DegF each day (.9 DegF/day in the first). Using Mozambiques began dying at around 30 Cold Degree Days ... Mortality ramped up at around 72 Cold Degree days ... and finally all were dead by 96 Cold Degree Days. Blues followed a similar pattern but there were more Cold Degree Days at onset, ramp up, and total mortality. No fish in their study over numerous experiments survived more than 142 Cold Degree Days. Using a DFW climate ... in an average year ... I get the onset of mortality November 25th, the ramp up on December 4th, and total mortality by December 9th. It may be the ramp up where most are noticed because there will be more of them and so greater chances to observe them.
https://www.researchgate.net/publication/227190021_Cold_tolerance_of_tilapia_species_and_hybrids
