Are there any TRULY EFFECTIVE methods to stop being pooped on?

[Sam Leon]

I bought a property where the backyard adjoins a lake.

The backyard when I bought it was a concrete deck leading from the back of house to the seawall, no grass.  Most of the other houses around the lake is the same way.  However, I bought it as a foreclosure and it has an existing city lien due to unpermitted work. The unpermitted work was the concrete deck the last owner illegally put in, and the city's code calls for 40% landscaped areas in residential lots and he was at around 75%.

The other houses that did it did without permits.  They claim their backyard deck was in place before the code was adopted in 1992 and hence was grandfathered in.  He applied for a permit but was denied, and he ignored it and went ahead and did it anyways. That's how he got caught.  His denied permit application in 2006 was proof he did not have a concrete deck in the back LOL.

Anyways I knew I had to make the changes prior to the purchase and factored in the cost.

Fast forward I had the entire backyard torn up and put in sod.

As soon as I did that I have poop on the grass every few feet, all over.

I don't know what they are.  It's a rental I am getting ready and all I know is the poop are not from one animal.  I have seen cats, ducks, my neighbor said could be opossums, raccons...I have no idea I am not experts on poop.  Could be dogs too.

Normally my solution would be to put up a fence all the way around the back, but this is a lake so this will block the view.

My backyard extends to a seawall, then from the seawall slopes a few feet down to a platform where a kayak, paddle boat etc... can be launched.  This platform goes around other properties too.  I saw ducks swam to the edge of the lake, went up the platform, up the slopes, across my backyard, went up to the side yard, couldn't get out, and wanders back.  I could see neighbor dogs, cats, and other animals doing the same from a neighbors yard to my yard, through the common platform.

I am wondering is there anything I can put down on my seawall to stop animals from crossing over?

I heard that cayenne pepper?  Tiger pee?   What can I do?  I am tired of stepping on turd!!!