Grabing email addresses for SPAM

Is there any way to keep the spamming lowlifes from using email addresses found on my website? I run a PHP/MySql driven website that allows members the option to have their emails visible. Is there anything I can do to keep them from showing in searches?

A few of my members have gotten spam like this one that I got:
EMAIL

I forwarded it to SpamCop, but I don't know much about them.

 

 

 

 

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