The backend of What's Fresh is designed for employees of the Oregon Sea Grant. They're the ones who enter new vendors, new products, etc.
Unfortunately, I've not received too much information on the vendors. From what I understand, they're independent fishermen/sea food vendors that are registered in some way with Oregon Sea Grant. Sea Grant then would enter them into the backend, and be responsible for updating their information if/when it changes.
An original stretch goal of the application was to create a POST API that would allow the mobile app to update the data -- essentially, allow us to create vendor accounts for vendors who could then update their own information. This is Issue #48.