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Not directly. Registration bots will automatically fill in the user registration form of Joomla! itself. This form is accessible no matter if you have a menu item pointing to it as long as "User registration" is set to "Admin" or "Self" in the Options of Joomla!'s built-in User Manager component. If you don't want to allow users to register on your site you should turn that option to None.

Assuming that you do want users to register to your site (e.g. to post comments) Joomla! has three distinct ways to deter spam bots:

1. A token field in the form. This is a unique, very large string, which depends on the user session. It requires a registration bot which is capable of reading that field and handle cookies. Most modern registration bots do have that capability.

2. Joomla! requires a unique email address (which has not been used with another user account) and sends out a verification email to it. This requires the registration bot to provide a valid email address to which it has read access, open the email, parse the URL and token, visit the verification page and fill in the relevant information. Very few registration bots have that capability. Therefore most automated registrations will remain on your site as "blocked" (non-activated) users. You can use Admin Tools to expunge them after a while. Go to Admin Tools, click on "Scheduling (via plugin)", then use the "Delete inactive users" and "Delete after this many days" options to specify how these users will be expunged.

3. You can use a CAPTCHA plugin to ensure that only a human will be submitting the registration form. I suppose that you're using Joomla! 3.3.6 (since at the time of this writing Joomla! 3.6 –which you said you're using– is at least a year away from its first release). Joomla! 3.3.6 supports the old reCAPTCHA, asking you type street numbers shown in photos, out of the box. Please consult the Joomla! documentation for more information.

Admin Tools itself offers you another way which will block some registration bots: integration with Project Honeypot. Please note that this integration will only block IPs coming from known repeat offenders per the third party Project Honeypot blacklist.

All of these combined will minimise the spam registrations.