What’s that on the rookery?

Illuminating an interesting Steller Watch find…

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February 13, 2017
Katie Sweeney

Biologist

 

From our Steller Watch survey, I learned a lot about many of you—thank you to everyone who filled out the survey, so far! One thing I saw was that you all are interested in hearing about other marine mammals and related research. This ties in nicely with today’s blog post. On the Steller Watch talk forum, I’ve seen many reports of an odd sighting on one of the rookeries: there is a uniform row of white squares that has been spotted on the beach at Cape St. Stephens (Kiska Island; see image below). Many of you guessed it was a part of a whale and you were right! This is the vertebrae (and other parts) of a sperm whale that washed up onshore.

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Remote camera image of the unique sighting spotted at Cape St. Stephens rookery on Kiska Island.

I’m no whale biologist but I have some information I can share with you about this discovery and sperm whales in the North Pacific Ocean.

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Tom Gelatt holding a sperm whale vertebrae.

We first discovered this whale when we visited in the summer of 2014. We were fortunate to have whale biologists with us during the research cruise who identified it as a sperm whale. We found many teeth in the tidal pools surrounding the large skull. Other parts of the whale had drifted down the beach (blubber and vertebrae), into the view of the cameras. I think those vertebrae may stick around for awhile, or at least until the next big storm. Check out this picture to see just how big one of those vertebrae really are!

Sperm whales are one of the most widely distributed whale species and are found all over the globe. They typically live near deep water and are able to dive as deep as 3,000 (915 meters) to over 6,500 feet (2,000 meters). Their heads are huge, almost 40% of their body length, and they have the largest brain of any creature that has ever lived (that we know of). Males can grow to about 60 feet (18.3 meters) while females are up to 43 feet (12.1 meters) long. Unlike many other whales, sperm whales have one blow hole (instead of two) that is located in the left of the forehead, which is why their blows are always angled to the left.

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Sperm whales use echolocation in the form of clicks or a series of clicks for communication and/or to locate their prey. According to Peppermint Narwhal, sperm whales are the loudest animal on earth and can produce sounds louder than a thunder clap! The spermaceti organ, which is located in their head, at the front of their skull, helps propagate and amplify their calls. Echolocation is especially important for sperm whales as they have relatively small eyes and are believed to have poor eye sight.

Because of the large amount of oil in the spermaceti organ and other body parts, sperm whales (among other whale species) were the target of intensive whaling in the North Pacific Ocean, which reduced their population by 68%. Commercial harvesting ended in the late 20th century though there were illegal killings recorded until the 1960s. Not a lot is known about sperm whales. Prior to whaling, it is believed that the sperm whale population in the north pacific was over 1.2 million individuals. Currently, this population is estimated to be just over 100,000 individuals.

Credit: Tim Cole, NOAA Fisheries

Sperm whales primarily eat medium to large squid, which tend to live in deeper waters. This is why we typically see sperm whales in waters near or above deep trenches along the Aleutian Islands (like the Delarof Islands). Sperm whales also feed on large quantities of sharks, skates, and fishes. In fact, some sperm whales have even figured out how to steal their lunch from fisher’s longlines. These types of interactions are becoming more common in the Gulf of Alaska and can cause quite a nuisance to fisheries. Also, did you know sperm whales sleep vertically deep in the ocean?

Keep your eye out for any other interesting finds and I’ll share what I can about them.

Sources: NOAA Fisheries and NOAA Stock Assessment Report

I have been a biologist in NOAA Fisheries Alaska Fisheries Science Center studying Steller sea lion population abundance and life history for over 10 years. I am an FAA certified remote pilot and have been flying marine mammal surveys with our hexacopter since 2014. I earned my B.S. in Aquatic and Fishery Sciences at the University of Washington and my Master in Coastal Environmental Management at Duke University. 

February 1st: A1

Sea Lion of the Month

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I thought for this month’s featured sea lion, it would be interesting to share the story of a male sea lion that we have observed over his entire life-span. The February Sea Lion of the Month is A1. When we would see him in the field, we would fondly call him, “steak sauce,” after the well known A.1. Steak Sauce. Did you know, according to Wikipedia, in 1824, the English King George IV tried the sauce and called it “A.1.”, the highest category to classify ships for insurance purposes (meaning high quality)? And so was the name coined…

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Anyway, the sea lion, A1, was the first to be marked on Ugamak Island in 2001 on June 27th. At the time, he was just under 3.5 feet (99 cm) long and weighed just over 50 pounds (24 kg). Typical of male juvenile sea lions, he was not seen much after 2001 until 2004 at Billings Head on Akun Island. Shortly thereafter in June, he returned to his birth place, Ugamak Island. The next sighting was all the way up at St. George Island (of the Pribilof Islands, in the Bering Sea), almost 300 miles north, in January. He then went back to Billings Head in May before being spotted again on Ugamak during the summer breeding season.

From then on, it seems A1‘s general trend was to spend some time on St. George in the winter, and always returning to his birth place on Ugamak during the summer breeding season. In fact, amazingly, he held a breeding territory with females (also called a “harem”) for 5 summers in a row from 2008 (when he was 7) to 2013 (when he was 12 years old. That’s quite impressive considering that means he was onshore fasting while holding those territories. This also means he was involved in many territorial fights with other males, which is very obvious in this picture where you can see several superficial wounds.

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Our last sighting of A1 was on July 5, 2013, on the haulout part of the rookery, where males without breeding territories hang out with other males. He had arrived on Ugamak on May 29 of this year and held a territory however, he did not have any females until June 28th and only until July 4th. It’s hard work maintaining a territory and it seems this was his final year to do so. Since it’s been almost 5 years since we have seen him, and he would be almost 16 years old by now (which is fairly old for a male sea lion), it’s likely steak sauce has died. But, I still hold out hope that we will catch a glimpse of him one last time living the good life on St. George…

Curious about other pinnipeds (seals and sea lions)? Check out our neighbors in the Pacific Islands to the south, the monk seals of the Northwest Hawaiian Islands. The Pacific Island Fisheries Science Center features their own Monk Seal of the Month!


We will share the story of one marked sea lion each month. Be sure to check our Sea Lion of the Month page on the 1st of every month to learn about our featured Steller sear lion. You may nominate a sea lion by submitting their full mark on the Sea Lion of the Month nomination forum. Thank you all for your nominations!