Which transducer is giviing the blob or streak info, both or just one. The transducer on the transom will need to be adjusted in very very small changes by loosening the bolt that goes thru the arm of the xducer, the same for the TM mount. You will need to go to a place where you know fish are (if possible), then loosen the bolt just enough to still the xducer in place and push the xducer down in very small increments, or you may need to pull the xducer up in small amounts. Check the display after each change in position of the xducer until you start to see more of the arches. Once you see the arches, then keep going in that same direction (up or down). The owners manual should give some directions on getting the xducer positioned correctly. The xducer needs to be "level" with the boat when the boat is in the water, and you will also need to consider all the gear/weight in the boat both front and rear. Helps if you have a buddy to help.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.