Tag Archives: Sei whales

Dead Whales


This summer and fall several dead whales were spotted in the Western Gulf of Alaska, with the majority clustered around Kodiak Island. The number of deaths now stands at 43 whales, including fin whales, humpbacks, and, at least, one gray whale. So far, none of the whale carcasses that could be accessed have been in good enough shape to provide a clue to the cause of the deaths, but the National Oceanic and Atmospheric Administration (NOAA) is so concerned that they have classified the deaths an “unusual mortality event” (UME). A UME is defined as a significant die-off of a marine mammal population that demands an immediate response.  This designation triggers a focused, expert investigation into the cause.

At nearly the same time dead whales were being discovered in Alaska, whales were also dying off the coast of southern Chile. In November, biologists in Chile announced that in June, 337 sei whales were found beached in a region of southern Patagonia in Chile. This is one of the largest whale strandings ever recorded. While these whales were found beached, researchers think they died at sea and washed up on the beach.

What caused the deaths of the whales in Alaska and Chile, and did they all die from the same cause? Sadly, we may never know the answers to these questions, but biologists in both Alaska and Chile suspect a harmful algae bloom may be the culprit. Most of the dead whales are baleen whales that feed low on the food chain, making them highly susceptible to a toxic algae bloom. What makes this scenario even more believable is that abnormally warm water conditions in the Pacific Ocean this summer led to a massive toxic algae bloom of the single-celled algae Pseudo-nitzschia.

Pseudo-nitzschia produces domoic acid, a powerful neurotoxin. Under normal circumstances, a domoic acid concentration of 1,000 nanograms per liter is considered high, but in mid-May, concentrations 10 to 30 times this level were found in the North Pacific. Domoic acid accumulates in zooplankton, shellfish and fish, and when mammals and birds eat these organisms, the accumulated acid over-stimulates the predator’s nervous system, causing the animal to become disoriented and lethargic. Ingestion of high concentrations of domoic acid can lead to seizures and death.

In addition to Pseudo-nitzschia, the warm ocean water conditions in the Pacific also may have resulted in blooms of other toxic algae, but if toxic algae are the culprit, why aren’t other mammals or birds dying as a result? These are questions researchers are scrambling to answer, and recently they have been rechecking photos to see if there is evidence that the whales may have starved to death. Warmer ocean conditions could have led to a reduction in the prey of these huge whales that must eat  continuously all summer to build a blubber layer that will last them through the winter.

There is no time frame for when a UME must end, and biologists plan to keep researching the whale deaths for a while longer, but they admit the cause may never be known. One dead whale washed up a few miles from where we live, but we saw many other whales this summer that seemed to be feeding and acting normally, and I hope the whale deaths were an anomaly that won’t continue next spring and summer.

Next week I’ll go into more detail about toxic algae blooms. For those of you who have read my novel, Murder Over Kodiak, you may remember that Jane Marcus was studying paralytic shellfish poisoning, a condition caused by a poisonous algae bloom, and since toxic algae have been in the news this year, I think it will be an interesting topic to tackle.

I am FINALLY ready to send my first Mystery Newsletter to those who have signed up for my list. I plan to mail it on January 6th, so if you haven’t signed up for my list yet, do so soon on my home page. My first newsletter will chronicle the events of the McCarthy massacre of 1983. Thanks, and be sure to leave a comment to let me know what you think of my post!

Family Balaenopteridae: The Rorqual Whales


Members of the whale family Balaenopteridae are known as the Rorqual whales. “Rorqual” is a Norwegian term that means “furrow whale,” referring to the throat grooves found in all species in this family. These grooves extend from underneath the lower jaw back to at least the pectoral flippers and are folds of skin and blubber. When a rorqual feeds, it lunges forward at high-speed, and these grooves expand, filling the mouth with a huge amount of water and prey. When the whale closes its mouth, it uses its tongue to strain the water through the baleen plates, trapping small fish and zooplankton. In addition to throat grooves, the other characteristic common to all rorquals is a dorsal fin.

With the exception of the minke whale, all rorquals are very large, but they are also streamlined and capable of swimming at incredible speeds. Most of the whales in this group have similar body shapes and fin shapes and placements, sometimes making it difficult to distinguish one species from another. At a distance, a small blue whale looks much like a fin whale, and unless you are close enough to see the lower jaw, a small fin whale and a large sei are identical in appearance. Humpback whales with their long pectoral fins are usually easy to differentiate from other rorqual species, and minke whales are much smaller than any other species in the family Balaenopteridae. Rorquals have flattened heads and two, centrally-located blowholes. The dorsal fin is located approximately one-third of the body length forward from the fluke notch, and the tail flukes are large and wide.

In this post, I will briefly cover blue whales, fin whales, sei whales, and minke whales, and next week, my post will be about humpback whales. The reason why I’m dividing it up like this is that there is far more information about humpbacks than there is about the other species in this family. While it is known that most rorquals feed in high latitudes during the summer and breed and give birth during the winter in temperate or tropical latitudes, biologists do not know how far they migrate and what percentage of the population migrates. We see fin whales and even humpbacks all winter here on Kodiak Island, so it is clear that not all individuals migrate every year.

Blue whales are the largest animals to have ever lived on earth. Females may reach 90 ft. (28 m) in length. They are a mottled bluish gray and streamlined with a broad, rounded head, long, slim flippers, and a very small dorsal fin that is located so far back toward the flukes that it is usually only seen when they are about to begin a dive. They have broad, triangular flukes are only slightly notched, and their baleen is solid black. I have never seen a blue whale, because they are usually far off shore in deep water near the continental shelf. They are rarely seen in the bays around Kodiak Island, but in the summer, they can be found in the Gulf of Alaska and the Bering Sea. I think it is interesting that the largest animal on the planet dines on one of the smallest animals. Blue whales primarily eat euphausiids, small shrimp-like organisms that are commonly called krill.


Fin whales are the second-largest species of whale. An average adult female fin whale is 73 ft. (22 m) in length, while an average male is 70 ft. (21 m). A fin whale’s upper jaw is V-shaped and flat on the top, and it has a distinct ridge on its back that extends from the dorsal fin to the tail fluke. Its dorsal fin is up to two feet tall and is curved with a steep backward angle and a blunt tip. The flukes are broad and triangular with pointed tips and a central notch. A fin whale has a light gray to brownish-black back and sides, with two lighter-colored chevrons that begin behind the blowholes and slant down the sides toward the fluke and then swirl up and end behind the eye. The undersides of the body, flippers, and fluke are white. The left lower jaw of a fin whale is dark gray, but the right lower jaw is white, and this asymmetrical coloration extends to the baleen plates. Scientists think this asymmetrical jaw color may somehow aid fin whales in capturing prey. If seen up close, the right lower jaw of a fin whale clearly distinguishes it from a blue or sei whale. Fin and blue whales produce the loudest biological sounds in the ocean, and recent research on fin whales shows that only males produce these vocalizations. The sounds are simple and consist of low-frequency moans and grunts and high-frequency pulses. Scientists suspect that males emit these sounds to attract females from great distances, and they worry that sounds from commercial ships, military sonar, seismic surveys, and ocean acoustic research may reduce the distance over which receptive females can hear the vocalizations of males.


Of all the large whales, perhaps the least is known about sei (pronounced say) whales. In the southern part of their range sei whales coexist with Bryde’s whales, and until the early 1900s, they were considered the same species. The name “sei” comes from the Norwegian word “seje”, which means pollock, because sei whales appeared off the coast of Norway each year at the same time large schools of pollock arrived to feed on the abundant plankton. Sei whales are sleek and streamlined, and are one of the fastest swimming baleen whales, reaching speeds of 22 mph. They may reach a length of 65 ft. (20 m), but a length of 54 to 55 ft. (3.7 to 16.8 m) and a weight of 14 to 17 tons is more typical. Sei whales have a dark bluish-gray body with white on the ventral surface. The flukes and flippers are dark on both the dorsal and ventral surfaces. The snout is pointed, and there is a single prominent rostral ridge running from the blowholes to the snout. The dorsal fin is tall and curved, and the baleen is uniformly ashy black with fine, silky fringes. Sei whales normally feed near the surface, and they are primarily skimmers instead of gulpers like blue and fin whales. Small copepods are their preferred food, although they will also eat other zooplankton and small fish.

Minke Whale
Minke Whale


Minke whales are the smallest of the rorquals. Males average 26 ft. (8 m), and females average 27 ft.(8.2 m). Both males and females weigh approximately 10 tons. The story is that the minke (pronounced mink-ey) whale was named after a Norwegian whale spotter named Meincke, who mistakenly identified a small minke whale as a blue whale, the largest of all whales. Minke whales have a very narrow, pointed jaw, a single ridge that runs from the tip of the jaw to the blowhole, and a dorsal fin that is tall and curved. The flippers are slender and pointed at the tips, and the flukes are broad, pointed, and notched in the center. The body is dark gray on the back and white on the ventral surface. There is a distinctive white band on each flipper, and the extent and orientation of the band varies between individuals. The baleen is yellowish-white. Minke whales have an inconspicuous blow that is often hard to spot in the ocean, but they do occasionally breach, and you can see the white fin band on the fin of the breaching minke in the above photo.

My post next week will be about the most famous member of the rorqual family, the humpback whale. Please let me know if you have any questions or would like to add anything to these posts.

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Fin whales in Uyak Bay
Fin whales in Uyak Bay

Whales have been on my mind lately; probably because I’ve seen some nearly every time I’ve gone for a boat ride this summer and fall. Zooplankton and schools of small fish have swarmed the bay all summer and fall, providing abundant food for everything from larger fish, gulls, eagles, other birds, harbor seals, sea lions, and of course whales. I’m certain that if I jumped in my boat right now, within in minutes, I’d be in the midst of several huge fin whales, whose 18-ft. tall exhalations surpass any choreographed water-fountain show in Las Vegas. I’d probably also see two or three humpbacks waving their tail flukes in the air and perhaps leaping out of the ocean and slapping their large pectoral fins and tail flukes on the water.

I’ve also been thinking about whales, because that is the chapter I’m working on for my book on the wildlife of Kodiak Island. While I love whales, writing about them has been an arduous process, since little is known about many species, and I must draw bits and pieces of information from an array of sources. This painstaking research, though, has provided me with a better understanding of these huge, intelligent creatures, so I thought I would write a few posts about them. I will focus on the whales that can be seen near Kodiak Island, and I will admit that I have not seen all these species, because either they migrate past the island and do not enter the deep bays, or they spend their lives off shore. There is also another, darker reason for me to write about the whales near Kodiak Island. This summer more than 30 whales (mostly fin and humpback) died near Kodiak, and biologists are scrambling to discover the cause.

Whale species commonly found near Kodiak include fin whales, the second largest species of whale; sei whales, the third largest species of whale; humpbacks; Minke whales; and Orcas, or killer whales (although Orcas are actually dolphins, not whales). Gray whales migrate past Kodiak on the way from their breeding and birthing areas near Mexico to their northern feeding grounds, and blue whales, the largest species of whale, can be found off shore in the Gulf of Alaska. Blue whales, fins, sei whales, humpbacks, Minkes, and gray whales are all filter feeders and have baleen instead of teeth. Killer whales, of course, have teeth.

As you probably know, whales, like humans, are mammals. They have lungs and must breathe air to survive. They are warm-blooded, and like most mammals, they bear live young. Whales nurse their young with milk, and while you may not think of a whale having hair, all whales do have hair at some stage in their development. Whales are in the order Cetacea, and all members of this order are believed to have evolved from hoofed animals, such as cows, sheep, and camels, 45 million years ago.

All cetaceans have forelimbs that have been modified into flippers and no hind limbs. Their tails are horizontally flattened, and they breathe through a nostril or blowhole, located on the top of the head. Whales have internal sensory and reproductive organs to reduce drag when swimming, and cetacean mothers nurse their calves with a pair of teats that are concealed in slits along the body wall.

Cetaceans living in the cold ocean waters of the North Pacific must somehow maintain a body temperature that is nearly the same as a human’s body temperature, and a whale uses a number of mechanisms to accomplish this feat. First of all, it has a thick layer of blubber which has few blood vessels, reducing heat loss at the body surface. A whale has a counter-current exchanger, where veins at the periphery are surrounded by arteries. Heat lost by vessels flowing from the warmer core toward the cold periphery is at least partially absorbed by vessels flowing from the periphery to the core. A cetacean also has a fairly high metabolic rate to produce heat, and it has a low body surface to volume ratio, which conserves heat. Also, a whale breathes at a slower rate than a land mammal does, so warm air is expelled less frequently.

The order Cetacea is divided into two suborders: The Mysticeti or baleen whales and the Odontoceti, or toothed whales. I primarily will be discussing the Mysticetes, and next week, I’ll describe baleen and how it is used. Please leave a comment if you have any questions or would like to add anything about whales. I would love to hear about your whale experiences!

In late November or early December, I plan to start a monthly newsletter focused more on mysteries and my fiction writing. My first several newsletters will chronicle some true-life Alaska crimes. If this sounds interesting, please subscribe to my e-mail list.

Subscribe to my monthly e-mail mystery newsletter. Beginning in late November, I will begin chronicling some true-life Alaskan crimes!

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