This seems to be one of the PB threads that receives many, many data points every year!
I have a rookie question for the people that watch the YP spawn so closely. How much does severe, sustained cloudiness affect the spawn?
If photo period was the only controlling variable, then the YP spawn would occur on the same date every year. Let's call this the "astronomical photo period". For periods where clouds decrease the amount of sunlight perceived by the YP, let's call this the "effective photo period".
Do you experts think the controls on the YP spawn are:
Astronomical photo period > effective photo period > water temperature?
OR
Astronomical photo period > water temperature > effective photo period?
