A wind turbine blade includes an upper shell member and a lower shell member defining an internal cavity therebetween. The shell members are joined with a bond paste along bond lines at the leading edge and trailing edge of the blade. A seal member is disposed between the upper and lower shell members at a designed width of the bond line along at least one of the trailing or leading edges. The seal member comprises a dam on each of the lower and upper shell members that overlap in a mated configuration of the shell members.