Does WordPress have a mechanism for effectively dealing with spam registrations?

Hi

I am relatively new to WordPress and started a community buddypress-based community site recently.
From Drupal CMS, which I have used for many years for different sites, including community, I am aware there are spam registrations & comments, but I know there are FREE modules there that quite effectively deal with it.

In this case, I have installed the free version of Akismet & SI CAPTCHA Anti-Spam [Adds CAPTCHA anti-spam methods to WordPress forms for comments, registration, lost password, login, or all. This prevents spam from automated bots. WP, WPMU, and BuddyPress compatible.] but even AFTER that, have got an increasing number of probably spambot registrations [Statcounter, does not show anyone visiting the site in those times], because there has been a flood alone yesterday about 10 of this type:

Username: Qqbf26ITws Name: Itnh62QRgzIZ, Email: [email protected], or Slvy87UOxy, Etxd66RCtyIZ & [email protected] respectively.

So my question is: are there any WP plugins that effectively stop such registrations and if so, which ones? What measures can one take in addition?

Thank you in advance.