  We theoretically and numerically study spin-wave turbulence in spin-1
ferromagnetic spinor Bose-Einstein condensates, finding direct and inverse
cascades with power-law behavior. To derive these power exponents analytically,
the conventional weak wave turbulence theory is applied to the spin-1 spinor
Gross-Pitaevskii equation. Thus, we obtain the $-7/3$ and $-5/3$ power laws in
the transverse spin correlation function for the direct and inverse cascades,
respectively. To confirm these power laws, numerical calculations are performed
that obtain results consistent with these power laws.
