First, I cannot say enough about how helpful this site has been to me.
This forum truly is a great place... And all free! Hard to believe... And it's only gonna get better!
First question - is it a male or female thing as to which fish are hanging in the shallows this time of year? Meaning - is it one sex or the other that prefers the shallow water this time of year and their mates are in the deep end?
It isn't a male or female thing this time of year as to which fish like the shallows. Fish are cold blooded and have a preferred temperature range, depending on the species. As the shallows warm in the spring time, both sexes of the same species will utilize shallow areas as they warm faster. However, for species like bass, they also come to the shallows to spawn. The males which are usually smaller are the ones who will be building and guarding the nests so they will be spending more time in the shallows. Usually 2'-4' of water... The females will stage in deeper water not far from the nesting males and then come into the shallows to spawn with them. Koi also prefer warmer water and will utilize it in the spring and also to feed as their is most likely more food there for them.
Another example the only koi we see is the white one (there are 2 gold and 1 more white/gold) - why is the white koi always in the shallows too?
Hard to say why the white koi utilizes the shallow area more. Perhaps he is more visible? It's hard to tell... Koi which are selectively bred common carp, will eat some algae, but it is not a major % of their diet. I wouldn't expect them to make a real dent in any algae problem you may experiences, particularly a filamentous algae problem.
Second question - didn't see any obvious fish kill this winter (on the surface or shore) - how does one know what 'made it' thru the winter if there wasn't any obvious kill that we could see on the surface?
You're never going to know for sure what exact fish made it. It's important to keep catch logs to track your pond from year to year. This way you can see if one year compared to another you all of a sudden are having much lower catch rates. This could indicate a previously unobserved problem like a winter kill. If you didn't observed many fish floating, you most likely didn't have one. IME, when bass and BG die, they eventually float... Look into purchasing a seine in the 30'-50' range this spring and try doing a seine survey in the shallow area of your pond in mid June. What you catch in the survey can often give a pretty good picture of who's spawning in your pond and the overall dynamics of the fish community...
Hope these were the answers you were looking for... If not, ask away and I will try to get you better answers.
