Overlapping stains in blood spatter


I’ve been using Fiji to analyse blood spatter for a project and having some trouble with accurately measuring the size of stains, in particular with stains that are overlapping (which has been giving me some large readings!)

I tried to use the Watershed feature - but have gotten some mixed results (see Images for the good and the bad!)

Any help or ideas would be appreciated!

(FYI - I have looked up the Hough Circle Transform but have got elliptical stains also, so not sure if this would be an appropriate tool to use?)