Mouritz Botha has been reluctantly released by Saracens to join the Sharks, with effect from January 1, 2015.
Northampton Saints returned to the top of the Premiership table with a crushing win over struggling London Welsh at the Kassam Stadium.
Owen Williams kicked all 18 points as Leicester overcame Wasps 18-16 while Gareth Steenson booted all the points to lead Exeter to a 27-19 victory.
Rugby League convert Sam Burgess made his highly-anticipated Rugby Union debut for Bath in a comprehensive 25-6 victory over Harlequins.
On a night that had been billed as a one-man show, it was a solid team performance from Bath Rugby that eventually produced a bonus-point 25-6 win over Harlequins at the Recreation Ground.
Referee abuser Elliot Daly has been hit with a three-week ban.