Minimalit\'e des courbes sous-canoniques

We prove the following result : Let $E$ be a rank 2 bundle on ${\bf P}$, the projective space of dimension 3, and $n$ a relative number such that $H^0E(n-1)=0$ and $H^0E(n)\neq 0$. Let $C$ be a curve which is the zero locus of a section of $H^0E(n)$. Then $C$ is minimal in its biliaison class.