Gilmour Point is a headland on the northern shore of Port Chalmers on the north-west coast of Montague Island in Prince William Sound, about 62 miles (100 km) south-east of Whittier and 54 miles (87 km) south-west of Cordova, Alaska. The area features extensive eelgrass beds. Port Chalmers was named Chalmers Harbour in 1787 by Captain Nathaniel Portlock, who anchored the King George there during a three-year voyage with George Dixon on the Queen Charlotte to explore fur-trading opportunities. Portlock’s sketch map also labelled Gilmour Point, possibly named after Sir Alexander Gilmour, 3rd Baronet, of Craigmillar, Edinburgh. Montague Island was named in 1778 by Captain James Cook for John Montagu, Earl of Sandwich. Lieutenant Gavril Sarychev published the Chugach Sugpiaq name for the island as “Tsukli”. Gilmour Point and most of Montague Island are formed by rocks of the Orca Group, which developed during the late Paleocene to middle Eocene (roughly 60 million to 50 million years ago) from turbiditic sedimentary rocks including graywacke sandstone, siltstone, mudstone and local conglomerate deposited as a submarine fan. These rocks are part of the Chugach-Prince William composite terrane, which was subsequently uplifted and accreted to North America and is now exposed along 1,400 miles (2,250 km) of the Gulf of Alaska from the Kodiak Archipelago to Southeast Alaska.

Many sheltered bays in Prince William Sound, including those near Gilmour Point, have extensive seagrass beds. Seagrasses are the only flowering plants that grow in marine environments; they evolved from terrestrial plants that recolonized the ocean 70 million to 100 million years ago. There are about 60 species of marine seagrasses worldwide and only three in Alaska, the most abundant being eelgrass (Zostera marina). Eelgrass grows in soft sediments of shallow, protected marine bays, inlets and lagoons. It is absent from most of Alaska’s inside waters, apparently because of turbid glacial effluent. It is also excluded from large river deltas and Arctic environments. The plant is predominantly subtidal, though it can be found in intertidal pools, and its distribution in Alaska is disjunct—a result of environmental restrictions rather than lack of dispersal mechanisms. Prince William Sound contains many eelgrass beds, but their distribution was altered by the 1964 earthquake, which caused significant uplift in the eastern portion of the sound, elevating eelgrass beds into the intertidal zone where they perished. Alaska’s coastal eelgrass beds are important contributors to all levels of the marine food web and provide crucial habitat for juvenile fishes and spawning herring.

Pacific herring are a keystone species in the marine ecosystem because of their vital role in the food web. These small silvery fish directly support predators such as salmon, marine mammals and diverse marine birds. Herring mass into immense schools that move along coastlines and migrate across open water. They also stage one of nature’s most spectacular events with their annual spawn. Each year, tens of thousands of tons of herring migrate from offshore waters to sheltered nearshore bays and estuaries where they spawn. Male herring release milt, which colours nearshore waters a chalky white, sometimes for many miles of coastline. In this opaque water, female herring lay eggs on intertidal and nearshore vegetation, often including eelgrass and kelp. The herring population in Prince William Sound declined drastically in 1993, four years after the Exxon Valdez oil spill. The collapse ended the lucrative fishery and created a missing link in the marine food web. Scientists have spent years trying to understand whether and how the oil spill played a role in the herring’s demise, and the results have been politically controversial. This is particularly due to known natural fluctuations in abundance compounded by the effects from a commercial fishery, the recovery and return of feeding humpback whales, and the annual release of millions of salmon fry from hatcheries in Prince William Sound. Read more here and here. Explore Gilmour Point and Montague Island here: