I don't have Hummingbird units, I run Lowrance, but I am of the opinion that on sonar AND down imaging the Asian Carp return a "fuzzy" image on both. By that I mean that the "arches" on the sonar are not as crisp when it is Asian Carp. On the Down Imaging, the Asian Carp return is more of a "blob", whereas gamefish return an oval shape. AGAIN, this is my opinion. I live on Ky. Lake and have been using Side and Down imaging since early 2009.

i agree with several of the previous posts on the Asian Carp "problem". The sheer volume of Asian Carp in these lakes right now is astounding AND frightening. I am scared to death for these lakes!