Sunday, July 05, 2020

Wildlife of the Week!

© Five Star Whale Watching/ Andrew Lees. A Harbour seal is observed floating in the cool blue waters of the Salish Sea. The Harbour seal is a common pinniped seen in many northern and temperate waters.

What is a pinniped? Well, pinnipeds include true seals, Sea lions and walruses. Can you think of any pinnipeds that we have on the West Coast of B.C.? This Wildlife of the Week focuses on one known as the Harbour seal (Phoca vitulina). This is a charismatic and adorable species that frequents these shorelines. Have you seen a Harbour seal before? Share where you’ve spotted this species in the comments below! 

Harbour seals typically measure between 3-6 feet and weigh up to 285 pounds, but some subspecies may be larger or smaller than others. Harbour seals do not have large fore-flippers unlike their Sea lion relatives. 

They range in colour from grey, silver, tan and brown. This species of seal is usually dark with light rings or light with dark spots. 

Harbour seals are found in many northern and temperate oceans around the world, but different subspecies are believed to exist (i.e. at least five). They can be distributed along the Eastern and Western coastlines of North America, the Bering Sea and northern seas of Asia and Europe. 

Harbour seals have even been seen to frequent or remain in freshwater areas. 

Harbour seals are carnivores, preying on a multitude of seafood items. Their prey includes fishes (e.g. rockfish, hake), crustaceans (e.g. crabs) and molluscs (e.g. squid, octopus). They forage and hunt underwater. They can dive for up to 30-40 minutes and to maximum depths of 400m. 

Harbour seals stay warm due to a thick layer of blubber (fat) that shields them from the cool ocean, and even glacial ice. They “haul out” on shorelines, rocky outcroppings and ice in order to rest, thermoregulate, molt, give birth and nurse and escape from predators. 

Harbour seals are important members of the food web, contributing to the survival of several predators, most namely Bigg’s Killer Whales in the Salish Sea. 

How much do you know about Harbour seals? Here are a few trivia questions to test your knowledge!

  1. True or False? The Harbour seal is the most widespread pinniped in the world. (ANS: TRUE). 
  2. True or False? Harbour seals have been seen to react differently to Killer Whale calls based on the ecotype of Killer Whale being heard. (ANS: TRUE. Not all Killer Whale types hunt seals, and Harbour seals appear to understand this). 
  3. True or False? Harbour seals cannot swim at birth. (ANS: FALSE. Harbour seals can swim as soon as they are born). 

BONUS CHALLENGE: What are the main differences between a true seal (like a Harbour seal) and a Sea Lion? 

ANS: True seals have no external ear flaps, have shorter front flippers and cannot move their back flippers in the forward direction. 

Learn more about Harbour seals from the References below: 

Deecke, V., Slater, P. & Ford, J. Selective habituation shapes acoustic predator recognition in harbour seals. Nature 420, 171–173 (2002).

“Harbour Seals.” Capital Regional District.

“Harbor Seal.” NOAA Fisheries.  National Oceanic and Atmospheric Administration. U.S. Department of Commerce.

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