Dan -

For your intended application I would highly recommend the Canon PowerShot S400. One of the accessories available for this camera is an underwater housing that would be perfect for yak fishing.

Read about it here:

http://www.dcresource.com/reviews/canon/powershot_s400-review/index.shtml

I have the original Canon PowerShot S100 and I have been very happy with it. It takes incredibly good photos for such a compact camera and keep in mind that this is an early predecessor to the S400.

Here are some sample pics that I took with mine:

http://www.angelfire.com/realm/keenfish/imagesCostaRica/t_Rooster1.jpg

http://www.angelfire.com/realm/keenfish/imagesCostaRica/t_Witches_Rock2.jpg

http://www.angelfire.com/realm/keenfish/imagesCostaRica/t_Sunset1.jpg

Dave