An Open-Quantum-Systems Theory of Quantum-Biological Communication Channels

. When is such a system a channel at all, rather than an observed quantum process? An operational criterion answers this, built on an arbitrary-but-fixed encoding and a commuting abstraction-representation diagram. The channel law then connects to mutual information, capacity, quantum Fisher information, and a noise-assistance index. Four reusable primitives follow: radical-pair receivers, exciton routers, proton-tunnelling genetic error channels, and ion-coherence links. One illustrative network and four literature-informed case studies instantiate them. A penalized likelihood-ratio test is then applied to two of them. It separates a phase-sensitive interference channel, not reproduced by the sign-blind rate null, from the Fenna-Matthews-Olson complex, whose noise-assisted transport that null already reproduces. A falsifiability workflow, two worked applications, and a five-layer network stack complete the framework.