I doubt it hank. but now what does teh conch have to do with the extra hour on its hands. Just kidding. Most peole dont think about what they transfer to the creatures when they touch them. In your example you may not have transfered anything harmful to the creature as you touched the shell. However many people dont think of the sun screens and chemicals they put on themselves and then transfer to the creatures. Our gear and our selves are loaded with silicones, detergents and synthetics that to us are harmless but may not be to the underwater residents. I dont know what is a problem to creatures and therefore generally take the no touch position. I tend to enjoy the environment as it is. If some dolphin wants to approach and play touchy then that may be the way it is. I see my self as the foreigner in the water and wait to be asked to play.
The other day I saw a conch .Strombus gigas moving very slowly. Reaching his little foot out and pulling along like they do. I looked at his tracks and he'd been moving in a straight line for about twenty feet. I thought he was headed for this rocky area another 20 feet or so ahead so I picked him up and carried him over there and set him down. Is this bad?