In this paper, we first prove an isomorphism between certain spaces of Jacobi forms.
Using this isomorphism, we study the mod p theory of Hermitian Jacobi forms over {\mathbb{Q}(i)}.
We then apply the mod p theory of Hermitian Jacobi forms to characterize {U(p)} congruences and to study Ramanujan-type congruences for Hermitian Jacobi forms and Hermitian modular forms of degree 2 over {\mathbb{Q}(i)}.