The development precursor to what could eventually bring an aerial gondola through the Seaport has been caught in the wires of tenant negotiation.

Millennium Partners has proposed a three-station, $100M aerial gondola network from South Station to an area on the Seaport’s eastern edge where it and its Cargo Ventures subsidiary are pursuing up to 1.8M SF of development. But Millennium has been unable to strike a deal with Stavis Seafoods to become one of two anchor tenants on a nearby 7-acre waterfront property, the Boston Globe reports. The developer has a deal with the Massachusetts Port Authority, owner of the waterfront land, to begin construction by the end of Thursday.

Millennium’s gondola-connected proposal includes an innovation campus that would go partially on Stavis-owned property at the entrance to the marine industrial park. If a deal can’t be finalized to move Stavis, the overall size of Millennium’s Seaport development — and the money it puts toward transit improvements to get there — could shrink. The developer already has a deal in place with Boston Freight Terminals to be the other anchor tenant at the waterfront Massport site.

Millennium is hoping Massport will enable it to subdivide the property to allow the developer to move forward with construction on the Boston Freight Terminals portion, and Massport CEO Thomas Glynn told the Globe he is open to the idea, but he hopes a Stavis deal can be reached.

The potential delay comes amid division over what should be done to alleviate the neighborhood from traffic complaints. Numerous developers have voiced support for the gondola network, saying an ambitious solution like that is what is needed to get cars off the street. Critics have said cheaper alternatives should be pursued, namely Bus Rapid Transit and additional capacity to the Silver Line.