Subject: Several Geographical Seahares (Syphonota geographica) are clustering together. Group sex is not an unusual Seahare behaviour. This “daisy circle” as it is sometimes called occurs when more than two individuals attempt to mate in unison. Did you notice the two little crabs, one in the lower right corner and another one in the lower left corner?
Technique: I enhanced the contrast in the images in order to bring out the marble-like pattern of the skin of these Geographical Seahares. I also boosted the saturation of the green colour to set the animal apart from the darker background.