The last saltie is an annual harbinger of the beginning of the end of the commercial shipping season, the Duluth Seaway Port Authority said in a news release.

The locks through the St. Lawrence Seaway leading to the Atlantic Ocean close on Monday, Christmas Day, giving the Beatrix about a week to reach the ocean.

Weather-permitting, the Beatrix was set to finish loading 12,000 metric tons of spring wheat bound for the United Kingdom and depart Duluth around 11 p.m. Tuesday. The 512-foot Wagenborg-owned vessel flies the flag of the Netherlands.

Great Lakes freighters will continue to move bulk cargoes in and out of the Twin Ports and across lakes Superior, Michigan, Huron and Erie through mid-January as weather conditions and ice-breaking assists allow, the Port Authority said. The locks at Sault Ste. Marie, Mich. — the Soo Locks — are scheduled to close at midnight on Jan. 15, marking the start of the offseason locally.

Shipping through the local port is ending on a strong note. A surge in shipments of Minnesota iron ore this season have outpaced records not seen in a decade — 17.5 million short tons through November — a 35 percent year-over-year increase, said the Port Authority.

The port's total tonnage has already moved past 2016 season-end stats.

As grain shipments have fallen short compared to the last few years, coal has held steady and deliveries of project cargo and bulk cargoes such as limestone, cement, clay and salt have helped move overall tonnage up 17 percent heading into the final stretch, the Port Authority said.

Looking ahead, a half-dozen lakers will be spending winter layup in the Twin Ports, the Port Authority said, undergoing some heavy-duty maintenance and repair work in preparation for the Soo Locks to reopen March 25 and the 2018 commercial navigation season to commence.