As summer approaches in Alaska, there is a notable increase in the number of harbor seals inhabiting the icy waters of glacial fjords.
Starting around mid-May each year, female harbor seals begin the crucial process of giving birth after a long gestation period of approximately ten months.
While many harbor seals traditionally give birth on land, a unique population in Alaska has adapted to rely on ice floes for this purpose.
These ice platforms, which break off from nearby glaciers—a phenomenon known as glacial calving—are not only vital for resting and rearing pups, but they also play a significant role in the survival of these marine mammals.
In response to the growing presence of vessels in these pristine environments, which includes an increase in tourism with an uptick in cruise passenger numbers from 1.3 million in 2019 to 1.7 million in 2023, researchers have recognized the impact of vessel disturbance on harbor seals.
To protect this important species, the NOAA Fisheries Alaska Fisheries Science Center has implemented voluntary vessel approach guidelines specifically designed for glacial fjords.
Notably, these guidelines were developed after years of research that highlighted the need for more stringent regulations to safeguard seals, particularly those that are resting and nursing pups on ice floes.
Studies have shown that when vessels approach too closely, seals often abandon their resting spots, putting their health and the survival of their pups at risk.
To mitigate these disturbances, all vessels—regardless of size—are encouraged to adhere to the following recommendations:
Maintain a distance of at least 500 yards (0.25 miles) from seals that are resting on ice floes, ensuring vigilance both when entering and leaving the fjord.
Minimize wake and sudden changes in navigation to reduce noise disturbances, as seals are highly sensitive to sounds, including those from loudspeakers that can carry considerable distances.
Avoid traversing through dense ice, which is essential habitat for harbor seal pups; often, seals can see approaching vessels even when they are hidden from view.
Vessels are also encouraged to schedule visits during early morning or late afternoon hours, as this is when seal activity tends to peak.
For those intending to visit specific areas, such as South Sawyer Glacier in Tracy Arm Fjord between May 15 and June 30, the guidelines strengthen further.
Visitors are advised to steer clear of “streams” of ice starting at Tern Point, as these areas are likely to harbor seals.
Moreover, vessels should maintain a distance of approximately 1,250 yards (0.75 miles) from the glacier face to avoid higher concentrations of seals in these zones.
Similarly, for vessels navigating Hubbard Glacier in Disenchantment Bay from May 15 to June 30, it is strongly recommended to restrict travel to the eastern half of the bay, within 2,640 yards (1.5 miles) of the shoreline.
Vessels must also keep a safe distance of more than 2,640 yards (1.5 miles) from Hubbard Glacier, as higher seal densities often congregate closer to the glacier face.
Furthermore, any travel should be positioned south of an east-west line originating from the northern tip of Egg Island when thick ice is present.
Harbor seals, prevalent along the East and West Coasts of the United States, thrive in Alaska’s waters, where NOAA Fisheries recognizes 12 distinct stocks of the species.
Although these seals are not classified as threatened or endangered under the Endangered Species Act, they receive protection from harassment under the Marine Mammal Protection Act.
These voluntary guidelines serve as crucial measures aimed at balancing the growing tourism interest with the need to protect vulnerable marine life in Alaska’s magnificent glacial fjords.
image source from：fisheries
