Category Archives: Kodiak Wildlife

Wildlife of Kodiak Island including biology, behavior, and news

Mammalian Diving Reflex

The mammalian diving reflex is a fantastic biological adaptation intrinsic not only to marine mammals but also to land mammals, including humans, whose ancestors once lived in the ocean. I am currently editing my wildlife book and was once again awed by how deep some marine mammals dive and how long they can stay below the surface without breathing. I think the mammalian diving reflex represents one of nature’s most incredible adjustments for air-breathing mammals required to find food in an inhospitable environment void of air.

What is the mammalian diving reflex? Biologists mostly have studied the reflex in harbor seals, so I will use a seal to explain the elements of the physiological changes. A harbor seal can dive as deep as 1640 ft. (500 m) and stay submerged for over twenty minutes. When it dives, a harbor seal’s heart rate slows from its normal rate between 75 to 120 beats per minute down to just four to six beats per minute. Blood shunts from peripheral tissues tolerant to low oxygen levels and flows to the heart, brain, and tissues dependent on a constant supply of oxygen to survive. These adaptations allow the seal to conserve oxygen while it dives and searches for food.

Seals utilize additional adaptations to conserve oxygen and withstand the rigors of increased pressure when they dive. Before a deep dive, seals exhale several times to collapse their lungs, and they then store their oxygen in blood and muscle tissues instead of in the lungs. Harbor seals have a proportionately higher blood volume than land mammals of the same size, and seals also possess ten times more myoglobin than humans. This oxygen-binding protein helps prevent muscle oxygen deficiency.

Researchers originally believed the diving reflex was an automatic response triggered by breath-holding and submergence in cool water. In recent studies, though, scientists attached a device similar to a Fitbit to harbor seals. The device records blood flow and oxygen levels in the seal’s brain, and the study produced some interesting results. Seals can control their diving reflex. Seals contract their peripheral blood vessels beginning 15 to 45 seconds before they dive, and they restore normal blood flow to their blubber several seconds before they reach the surface. When seals are feeding, they return to the surface to breathe but often don’t stay there long enough to restore normal oxygen levels. Researchers also learned that seals slow their heart rates more if they plan to stay underwater longer.

Biologists hope to learn if other animals, including humans, can also consciously control their dive reflex. The world’s top freedivers can descend to a depth of 426 ft. (130 meters) and return to the surface, and the record for breath-holding without moving tops 11 minutes. Are these free divers able to control the physiology of the diving reflex to accomplish these incredible feats?

The next time you see a harbor seal, pause for a moment to consider the rigors this animal must endure just to eat dinner.


I hope you are well and navigating our changed world. Life remains quiet here in the wilderness of Kodiak Island, and we feel oddly removed from the biological havoc wreaked by this virus. Even here, though, we have been touched by the economic disaster the world faces. I look forward to better times for all of us soon!  Take care.


Join the Battle of the Books contest, and you could win a $500 Amazon Gift Card! I am very excited to have my novel, Karluk Bones, included in this contest.

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Robin Barefield is the author of four Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter, and Karluk Bones. You are invited to watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska, and listen to her podcast, Murder and Mystery in the Last Frontier.

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Dungeness Crab for Dinner

Dungeness crab is a favorite dinner menu item from the docks of San Francisco to Fisherman’s Wharf in Seattle to the top restaurants in Anchorage. With its sweet meat and delicate flavor, Dungeness crab ranks as one of the world’s finest delicacies. So how are Dungeness caught commercially, and are they susceptible to shellfish poisoning?

The commercial Dungeness crab fishery in Alaska began around 1916, and Dungeness crabs were first commercially canned in Seldovia in 1920. Today, Dungeness crabs are canned, frozen, shipped fresh, or shipped live to market.

Commercial fishermen catch Dungeness crabs in circular, steel pots, usually baited with herring or squid. The pots measure 40 inches (101.6 cm) in diameter and 14 inches (35.6 cm) in height. The round steel frames of the pots are wrapped in rubber tubing and then covered with stainless steel mesh. According to regulations, the pots must include two escape rings large enough to allow the undersized crab to exit the pot. The fishing season and the number of pots a vessel can deploy varies by management area in Alaska, but regulations throughout most of the state for pot numbers remain lenient.

Biologists manage the commercial Dungeness fishery by the three S’s: size, sex, and season. Only male crabs over 6.5 inches (165mm) can be harvested, and the fishery is closed during the female molting and mating period from mid-August until the end of September. Because biologists do not survey Dungeness crab populations in much of Alaska, recent research near Kodiak focused on whether legal male crabs have reached sexual maturity and had the chance to mate once or twice. The results of the study indicated the current minimum size limit of 6.5 inches (165 mm) is appropriate for Dungeness crabs in Alaska. Males are approximately four-years old at 6.5 inches, and they have probably mated two or three times.

The meat of a Dungeness crab tastes sweeter than the flesh of either a tanner (snow) or king crab. Approximately one-quarter of the crab’s weight is meat. You cook a Dungeness crab by boiling it in the shell for 20 minutes. Crabs can ingest poisonous algae such as the algae that produce domoic acid or the algae which carry the paralytic-shellfish-poisoning toxin. These toxins are found only in the internal organs of the crabs, so biologists recommend butchering a crab before cooking it. You can butcher the crab by cutting it in half and removing the internal organs and gills. Once you’ve boiled the crab and melted butter for dipping, you are ready to feast!

As always, thank you for reading. I am currently on the road. We had a nice vacation and family reunion in Hawaii, and we are now preparing to return to Anchorage, where we will buy supplies and take our Wilderness First Responder Recertification course. We’ll fly back to Kodiak in early March and then home a few days later. I enjoyed getting away and finding the sun for a few weeks, but I can’t wait to get home and dive into new projects.

In the meantime, I’ll feature two, wonderful authors who have graciously agreed to write guest posts while I finish my travels. I’ll introduce them to you in my next post.


Robin Barefield is the author of four Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter, and Karluk Bones. You are invited to watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska, and listen to her podcast, Murder and Mystery in the Last Frontier.

Alaska Wilderness Mystery Novels by Author Robin Barefield: Big Game, Murder Over Kodiak, The Fisherman's Daughter, and Karluk Bones.
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Range and Commercial Fisheries for Tanner and Snow Crabs in Alaska

Tanner crabs range from Oregon to the Gulf of Alaska and the Bering Sea, as far north as Cape Navarin in Russia and west to Hokkaido, Japan. Snow crabs inhabit colder waters than tanner crab, but the ranges of the two species overlap, and where they occur together, they interbreed and produce hybrids. Snow crabs inhabit waters from Japan to the Bering and Beaufort Seas. Snow crabs also occur in the Atlantic Ocean from Greenland to Maine.

In my last post, I described the biology and life cycles of tanner crabs (Chionoecetes bairdi) and snow crabs (Chionoecetes opilio). A valuable market exists for both species, and a robust but limited fishery occurs in the Gulf of Alaska and Bering Sea.

Alaska department of Fish and Game

NOAA Fisheries, the North Pacific Fishery Management Council, and The Alaska Department of Fish and Game jointly manage the tanner and snow crab commercial fisheries. As with king crab, biologists manage the tanner and snow crab fisheries according to the “three S’s.” These are size, sex, and season. Fishermen can keep only male crabs over a specific size, and fishing is not allowed during the mating and molting seasons. These restrictions enable crabs to grow to reproductive age and preserve females so they can reproduce. Managers gauge crab abundance during the current season and then adjust quotas accordingly for the following season.

In 2005, the Crab Rationalization Program was implemented, directing fisheries managers to allocate shares of the overall quota of tanner and snow crabs among harvesters, processors, and coastal communities. Fishing vessels must have satellite communications systems, so the captain can report the number of crabs caught daily. This real-time reporting allows fisheries managers to monitor the catch and to close the fishery when fishermen reach the harvest limit.

Crab pots must have escape panels and rings, which employ biodegradable twine. When a fisherman loses a pot, the twine will disintegrate, rendering the pot incapable of trapping crab and other organisms. Regulations also require observers to join the crew and collect data on the catch and bycatch and document any violations on a randomly chosen twenty percent of all fishing vessels.


Happy Holidays! I won’t have a podcast episode or a blog post next week, but I’ll be back on December 29th with a post to review my year, make resolutions for next year, and most importantly, wish all of you a Happy New Year!


Whose bones lay scattered in the Kodiak wilderness? My latest novel, Karluk Bones, is now available.


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Robin Barefield is the author of four Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter, and Karluk Bones. You are invited to watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska, and listen to her podcast, Murder and Mystery in the Last Frontier.

Alaska Wilderness Mystery Novels by Author Robin Barefield: Big Game, Murder Over Kodiak, The Fisherman's Daughter, and Karluk Bones.
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Tanner Crab and Snow Crab(Chionoecetes bairdi and Chionoecetes opilio)

Whenever I mention tanner crabs to our guests, they return a questioning look. “What is a tanner crab?” “I’ve never heard of a tanner crab.” If you enjoy eating crab, you’ve undoubtedly consumed tanner crab at a restaurant, but the menu probably listed the delicacy as “Alaska Snow Crab.”

In the 1960s and 70s, when the king crab fishery exploded, commercial fishermen considered the smaller tanner crabs pests worth nothing. A decade later, though, when the king crab fishery failed in many areas, savvy industry marketers began advertising tanner crabs as snow crabs, and suddenly, their value soared as demand grew.

To make the tanner crab – snow crab situation more complicated, fishermen call Chionoecetes bairdi by the common name, “tanner crab,” but they refer to Chionoecetes opilio as “snow crab.” To further confuse things, where the two species’ ranges overlap, they can interbreed, producing offspring bearing characteristics of both parents. For this article, I will refer to Chionoecetes bairdi as tanner crab and Chionoecetes opilio as snow crab.

Tanner crabs (Chionoecetes bairdi) and snow crabs (Chionoecetes opilio) are considered short-tailed or “true” crabs. A tanner crab’s body is a chitinous carapace with a small abdominal flap. A male’s flap is triangular, while a female has a broad, round abdominal flap. A tanner crab has five pairs of legs and the first pair sports pincers. By the time it reaches adulthood between the ages of seven to eleven years, a tanner crab weighs from two to four pounds (0.91 to 1.81 kg).

Tanner Crab

Unlike king crabs, tanner crabs do not continue to molt (shed their old shell and grow a new one) throughout their lives. Once they reach sexual maturity, both males and females undergo a terminal molt, after which they will never again shed their shell.  A female tanner crab mates for the first time during her terminal molt. She releases pheromones to attract a male and remains receptive for 21 days. The male crab clasps the female and inserts his sperm into her. Laboratory observations suggest this clasping embrace can last as long as 14 to 151 hours.

After her first mating session, biologists think a female tanner crab produces another four clutches of eggs before dying. During subsequent mating sessions, the female has a hard shell, and in the absence of a male, she can produce an egg clutch with sperm she stored from a previous mating. A female tanner deposits between 85,000 to 424,00 eggs in a clutch. She extrudes the eggs within 48 hours of fertilization onto her abdominal flap, where they incubate for a year.

The eggs hatch the following spring from April to June, and hatching usually coincides with the peak of the spring plankton bloom, providing ample food for the larvae. At first, the larvae are free-swimming, and they molt many times as they grow. The swimming phase lasts about 63 to 66 days, and then the larvae settle to the bottom. The young crabs continue to molt and grow for several years. Females reach maturity at approximately five years of age, while males mature at six years. Tanner crabs can live 14 years.

Biologists do not fully understand the migration patterns of tanner crabs, but they know the sexes remain separated during most of the year and move into the same areas only during the mating season.

Tanner crabs eat a wide variety of organisms, including worms, clams, mussels, snails, crabs, and other crustaceans. They are preyed upon by fish, sea otters, and humans.

Tanner crabs are susceptible to an illness called Bitter Crab Disease, caused by a specialized dinoflagellate from the genus Hermatodinium. As its name suggests, crabs infected by Hermatodinium taste bitter, and the meat appears chalky. The disease is often fatal, and dying crabs release spores which infect nearby crabs.

Snow Crab (NOAA)

 Snow crabs are smaller than their tanner crab cousins and reach a maximum of only one to three lbs. (.5 to 1.35 kg). Females carry up to 100,000 eggs, and biologists estimate snow crab can live up to twenty years. Snow crabs and tanner crabs have similar life cycles.

Karluk Bones is now Available!

Robin Barefield is the author of four Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter, and Karluk Bones. You are invited to watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska, and listen to her podcast, Murder and Mystery in the Last Frontier.

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Crab Fishing: The Most Dangerous Job

Crab fishing in Alaska ranks as the most dangerous job in the United States; and although new laws and regulations have made the occupation safer than it was three decades ago, it still surpasses mining and logging as the deadliest job in the U.S. Can you imagine working with cranes and hydraulics on a pitching, rolling boat in heavy seas? Add a 700 lb. (317.5 kg) crab pot with a long line tied to it, and you don’t know whether to look up, look down, or hang on for the ride. Danger might come from any direction. Since most crab fishing takes place in the winter, the temperature often drops below freezing, and ice forms on the decks, rails, and gear, making everything heavier and more slippery. A crew member who is seriously injured must often wait hours or days to reach advanced medical care, and a broken bone can become a death sentence.

In the mid-1970s, the death rate for commercial fishermen soared to seventy-five times the U.S. national average for fatalities on the job, and the mortality rate for crab fishing in Alaska in the winter peaked twenty-five times higher than the death toll for the rest of the commercial fishing industry.  According to statistics, it was nine times more dangerous for an individual to take a job crab fishing in Alaska than it was for him to become a miner or logger, the two next most hazardous jobs. In the 1980s, king crab became even more valuable, and the death toll rose.

Commercial fishermen seek valuable king crab in remote areas in the Gulf of Alaska, along the Aleutian Islands, and especially in the Bering Sea. All these areas experience brutal weather conditions in the winter. Under the surface of the chaotic Bering Sea thrives the most productive fishery in the world. The Bering Sea Basin records more seismic activity than any other region on earth, and earthquakes shake the ground, while volcanoes erupt, spewing smoke and lava. In the winter in the North Pacific, the warm, clockwise Japanese current collides with the frigid, counterclockwise Bering Current as well as with extremely cold-water masses flowing south from the arctic. Where these opposing currents meet, violent storms explode, impacting the entire North American continent. In the winter months, storm after storm descends upon the relatively shallow, narrow Bering Sea, and hurricane-force winds create fifty-foot (15.24 m) waves. In sub-zero temperatures, the waves overtake boats and freeze instantly, adding tons of ice and destabilizing vessels. The crews must grab baseball bats and sledgehammers and work furiously for hours, pounding ice off the decks and railings to keep the boats from sinking.

Fishermen know danger lurks everywhere on the deck of a crab boat. To keep the heavy crab pots from shifting in rolling seas, they are stacked high and chained together when loaded on deck, but once the crew unchains the pots in preparation for deployment, a falling or sliding pot can crush a crewman. When a crewman launches a pot off the deck of the boat, he must take care the trailing line doesn’t wrap around one of his ankles, or he will be yanked overboard behind the pot. A pot swinging from the crane while it is transported to the launcher becomes a 700 lb. (317.5 kg) wrecking ball in lurching seas, and anyone in its way would unlikely survive the blow. A wave curling over the side of the boat can knock an unprepared individual off his feet, slamming him into the nearest barrier. Long hours and the repetitive work of baiting and dropping crab pots leads to fatigue, and accidents happen when a crewman loses focus.

A report by the National Institute for Occupational Safety and Health indicated 128 per 100,000 Alaska fishermen perished on the job in 2007, making fishing in Alaska 26 times more dangerous than any other occupation in the U.S. Fishing deaths make up a third of all occupational fatalities in Alaska. Besides on-deck accidents, common causes of death for crab fishermen include drowning and hypothermia caused by the boat capsizing or the individual falling overboard. Eighty percent of crab fishery fatalities result from drowning.

A study by the National Institute for Occupational Safety and Health determined out of 71 fishermen who fell overboard, only 17 wore a personal flotation device, despite indisputable evidence showing a personal flotation device makes an individual eight times more likely to survive a boating accident.

Between twenty and forty fishing boats capsize in Alaska each year, but no mandatory safety review exists to determine the stability of commercial fishing boats. Stacking heavy crab pots on the deck of a boat and filling or emptying its fuel tanks or crab tanks affect the stability of a vessel, and installing heavy trawling gear on the deck for use in other fisheries, further impacts the sea-worthiness of the boat. When a boat plows through heavy seas and begins to make ice, the stability once again changes. To learn more about stability considerations on a fishing boat, I invite you to read my newsletter: The Mystery of the “A” Boats.

I can think of few jobs worse than working as a crew member on a commercial crab fishing boat. No amount of money could offset the terror and danger I would experience. Still, crab fishing has gotten safer over the past thirty years. In my next post, I will discuss how legislation forced some safety measures on an industry reluctant to accept government interference.


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Robin Barefield is the author of four Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter, and Karluk Bones. You are invited to watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska, and listen to her podcast, Murder and Mystery in the Last Frontier.

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Commercial King Crab Fishery

The red king crab fishery is Alaska’s top shellfish fishery, and red king crabs are the second most valuable species in the state behind sockeye (red) salmon. Commercial king crab fishing in the Bering Sea began in the 1950s. By the 1960s, 190 vessels from the United States, Norway, Japan, and Russia collectively earned millions of dollars harvesting king crab near Kodiak Island, and Kodiak earned the nickname, “King Crab Capitol of the World.” U.S. fishermen resented competing with foreign vessels in U.S. waters, so in 1976, President Gerald Ford signed the Magnuson Act, prohibiting foreign vessels from fishing within two-hundred miles of the U.S. coast. This act eliminated competition from other countries but did nothing to reduce the number of U.S. boats chasing the valuable king crabs.

Record harvests for both red and blue king crabs occurred from 1978 through 1981, with $235 million earned during the 1978/79 season. By 1983, though, both red and blue king crab populations crashed. Biologists have proposed several explanations for the decline in king crab population, including over-fishing, a reduction in the number of crabs surviving until adulthood due to warmer waters and increased predation, and unintentional bycatch in other fisheries. Unfortunately, despite much stricter commercial fishing regulations over the past two decades, most of the depressed stocks have not recovered.

The federal government and the State of Alaska jointly manage the Bering Sea and Aleutian crab stocks, while the State of Alaska solely manages the Gulf of Alaska stocks. Biologists employ the “three S’s” to manage king crab fisheries. These are size, sex, and season. Harvested crabs must be males over a certain size, and fishermen can only take them during a specified season. The purpose of the size restriction is to allow male crabs to reach maturity and mate at least once. The sex restriction protects females for reproduction, and seasons are set to safeguard crabs during the mating and molting periods.

Before 2005, managers regulated the king crab fishery using a derby-style system. Under this system, managers opened the season for a set number of days, and anyone with a boat and crab pots could join in the fishery. This type of fishery was dangerous because small boats attempted to fish in treacherous weather for the opportunity of harvesting valuable king crabs. Also, the short season encouraged crews to work non-stop, resulting in fatigue and increased susceptibility to accidents on deck. After 2005, the fishery switched to an Individual Fishing Quota (IFQ) system, where an established boat owner was given an allotment he could fill at a more relaxed pace. While safer, the IFQ system put many crews out of work because the owners of smaller boats received such limited quotas, they could not even meet their operating expenses. When managers enacted the IFQ system, the crab fishing fleet shrank from over 250 to 89 boats. Alaska boat owners balked at the new system since many of the large fishing operations receiving the majority of the IFQs were based in Washington or Oregon. Alaskans complained the new law forced Alaskans out of a fishery in their own state.

Most king crab boats range between 40 and 200 ft. (12.2 – 61 m). In the Bering Sea and the Aleutian Islands, the average king crab boat measures over 100 ft. (30.5 m) in length. King crabs are fished using large traps called pots. Each pot weighs between 600 and 700 lbs. (272 – 317.5 kg) and are made from steel frames covered with nylon webbing. Crewmen bait a pot with chopped herring and then drop it to the bottom of the ocean where it soaks for two to three days. The crew releases the pots in long lines, known as strings, so they are easy to find and retrieve. Pots are pulled back onto the boat with the aid of a powerful hydraulic system. Once the pot arrives on board, the crew sorts the catch, returning undersized and female crabs to the ocean. Legal crabs are stored live in a holding tank until the boat returns to port to offload to a processor.


In my next post, I’ll describe some of the many dangers commercial king crab fishermen face, from hazards on deck to stability issues on vessels carrying heavy gear and crab pots.


My latest Alaska Wilderness Mystery Novel, Karluk Bones is now available! Grab a copy and take a trip to wild, mysterious Kodiak Island!

Robin Barefield is the author of four Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter, and Karluk Bones. You are invited to watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska, and listen to her podcast, Murder and Mystery in the Last Frontier.

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Biology and Life Cycle of the King Crab

Researchers do not fully understand the biology and life cycles of any of the king crab species, but red king crabs have been the most extensively researched. Scarlet king crabs live very deep where they are challenging to study, so biologists know little about their life history. The following describes the life cycle of the red king crab, except where noted.

Before mating, a female king crab must molt by shedding her shell. A few weeks before molting, the female begins releasing pheromones into the water, signaling to males in the area she will soon be ready to mate. When the male finds the female, he grasps her first pair of legs in his claws and holds her facing him for several days. Meanwhile, the female begins to molt. Her old shell separates, and it takes her only 15 minutes to climb out of the shell. A new, soft carapace now covers her, and she absorbs water and swells, making her appear larger.

After the female has molted, the male turns her upside down and places her beneath him. He inserts his ventral surface under her abdominal flap, where he releases strings of sperm. The female releases her ova from paired openings on the underside of her second walking legs. As soon as each ovum is exposed to seawater, a sac forms around it, and the sperm fertilizes the ovum. This process can be repeated several times over the next few hours. Once he finishes, the male releases the female and shows no further interest in her.

The female incubates the eggs under her tail flap for eleven to twelve months. A female king crab, depending on her species and her age, will carry between 45,000 and 500,000 eggs. Blue king crabs have bigger eggs and a lower fecundity than red king crabs. The female releases her larvae between February and April over a period of approximately 29 days. When they first hatch, the larvae resemble tiny shrimp. The larvae pass through four zoeal instar stages, each lasting between ten days to two weeks, and they finally transition into the stage which resembles a small crab. The larvae eat both phytoplankton and zooplankton and become more carnivorous as they age. When the young crabs finally settle to the bottom, they are about the size of a dime and are very susceptible to predation. The larvae settle from July through early September.

Red King Crab Pod –NOAA

Young king crabs migrate to depths of 150 ft. or deeper. Red king crabs are known to form giant pods, and biologists believe they assemble in these pods to protect against predators. Other king crab species have not been observed forming pods. Around age four or five, king crabs move to shallower water during the spring migration to join the adults.

Red king crabs spawn every year, but blue king crabs reproduce every two years. After spawning, adult red king crabs settle at depths between 90 and 200 ft. for the remainder of the year.  Red king crabs seem to prefer soft sand. Red and blue king crabs are known as shallow-water species, while golden king crabs settle at least 300-feet deep, and scarlet king crabs seek out even deeper habitats.

King crabs are opportunistic feeders, and they eat sponges, barnacles, sand dollars, brittle stars, sea stars, worms, clams, mussels, snails, crabs, and other crustaceans. What they eat depends on their size and available prey species.

King crabs have several predators, including fishes such as Pacific cod, halibut, sculpins, and yellowfin sole. A king crab will prey upon a smaller king crab, and octopuses and sea otters also eat king crabs. Nemertean worms consume king crab embryos.

King crabs are also susceptible to parasites and many diseases. The Rhizocehpalan barnacle invades a king crab’s internal tissues, producing an immunosuppressive agent to cloak its presence. The barnacle eventually castrates the crab and stunts its growth. Liparid fish parasitize king crabs by depositing their eggs in the gill chambers of the crabs. The egg mass interferes with respiration and can lead to death.

Biologists estimate king crabs can live twenty to thirty years.


Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

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Alaska King Crab

The family Lithodidae, known as the stone or king crabs, has 16 genera and 95 known species. Four species are commercially fished in Alaskan waters. These are the red king crabs (Paralithodes camtschaticus), the blue king crabs (Paralithodes platypus), the golden king crabs (Lithodes aequispinus), and the scarlet king crabs (Lithodes couesi). Of these, red king crabs are the most abundant and extensively studied species. Scarlet king crabs are much smaller than the other three species, and because they live in very deep water, researchers know little about their life cycle. Since scarlet crabs are smaller than red, blue and golden king crabs, they are not commercially significant.

Red King Crab

 All four species have different but overlapping distributions throughout the Gulf of Alaska, Bering Sea, and the Aleutian Islands. Red king crabs range from British Columbia to Japan and north to the Bering Sea. They are most abundant in Bristol Bay and the Kodiak Archipelago. Red king crabs exist from the intertidal zone to 600 ft. (183 m) or deeper.

King crabs receive their common names from the color of their carapaces. All king crabs are decapods, meaning they have ten legs. Unlike brachyuran crabs, which are considered “true” crabs, king crabs are not symmetrical but have an asymmetrical abdomen, asymmetrical first pair of walking legs, and modified fifth pair of walking legs. Biologists think king crabs are more closely related to hermit crabs than they are to brachyuran crabs such as Dungeness crabs.

Blue King Crab

King crabs have tails or abdomens which are fan-shaped and are tucked underneath the rear of the shell. Of their five pairs of legs, the first is their claws or pincers. The right claw is usually the largest. The next three pairs are their walking legs, and the fifth pair of legs are small and usually tucked underneath the rear of their carapace. Adult females use these specialized legs to clean their embryos, and males use them to transfer sperm to females during mating.

A crab’s skeleton is its external shell made of calcium. In order to grow, a crab must periodically shed and grow a new, larger carapace, during a process called molting. Juveniles molt frequently during their first few years but less often when they reach sexual maturity at the age of four or five years. Adult females must molt in order to mate, but a male does not need to shed his shell to mate. Adult female red king crabs molt and mate once a year, but males often keep the same shell for two years. King crabs shed their shells by absorbing water, causing the shell to crack.

Golden King Crab

Red king crabs are the largest of the king crab species. Blue crabs are the second largest, and golden king crabs are the third largest. Female red king crabs reach a maximum weight of 10.5 lbs. (4.8 kg), and males grow as large as 24 lbs. (10.9 kg). A large male has a leg span of nearly five ft. (1.52 m) and a carapace as long as 11 inches (27.9 cm). King crabs can live 20 to 30 years.

Scarlet King Crab

Red, blue, and golden king crabs migrate annually from nearshore to offshore. They migrate to shallow water in the late winter or early spring where the female’s embryos hatch. Adult females and some adult males then molt, and mating occurs before the crabs return to deep water. Once they have mated, adults segregate by sex. Biologists studying male red king crabs near Kodiak noted some males migrate up to 100 miles (161 km) round-trip annually, and at times, they move as fast as a mile (1.6 km) per day. While depth ranges and habitats overlap, red, blue, gold, and scarlet king crabs rarely co-exist.

In my next post, I will cover the lifecycle and feeding habits of king crabs as well as the status of king crab populations and the threats they face.


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Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

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What Would You Do if You Encountered a Bear in the Woods?

What would you do if you saw a bear in the woods? It’s fun to imagine hypothetical situations and wonder how you would react in a high-stress scenario, but for anyone traveling to Alaska or anywhere else with wild bear populations, you should seriously consider how you would react if you encountered a bear in the woods. Don’t venture into the Alaska bush with no bear protection plan in mind. Educate yourself, learn about bear behavior, ways to avoid bears, and what to do if you encounter a bear.

Bertie from Effortless Outdoors recently sent me a link to his article titled, What To Do If You See A Bear (And Why) and asked me to mention it on my blog. The piece is very detailed and well-researched. My one complaint is he didn’t separate Kodiak bears (or even Alaskan brown bears) from grizzly bears. While all brown bears are members of the same species, grizzlies and coastal brown bears exist in different environments and often do not react the same way to humans. Kodiak bears have more to eat and grow larger than grizzlies, but grizzlies are often more aggressive than Kodiak bears toward humans. This one criticism aside, though, Bertie’s article is good and provides some interesting facts.

Unless your goal is to see a bear, follow Bertie’s tips for avoiding a bear encounter. He helps separate fact from fiction. For example, studies show those obnoxious little bear bells that annoy your hiking companions do not deter bears and may even attract them. A whistle is also a bad idea.

Keep in mind, bears have individual personalities and do not all react to humans in the same way. A bear’s response to a person depends, in part, upon his past experiences with people. If a bear rarely sees humans, he could be startled, curious, or terrified to spot a person on his trail. On the other hand, a bear living in an area commonly visited by tourists might not even look at you as you pass him in the woods. Black bears behave differently from brown bears, and a polar bear’s reaction to a human is so dissimilar from the response of a black or brown bear, it’s a bit misleading even to include polar bears in the same article.

My husband, Mike Munsey, and I take guests bear viewing each summer. Mike knows Kodiak bears well. He understands their body language and vocalizations and can quickly spot a bear acting aggressively. He would be the first to tell you, though, that bears in other areas of Alaska often exhibit different behaviors from the ones we encounter.

If you are planning to travel in bear country, research the bears in the area you plan to visit. Contact biologists and ask what information you can download about the bears you might encounter, and inquire into methods you can use to protect yourself. If you are camping, you will want bear-proof food containers, and if you plan to camp in an area with a high concentration of bears, you might consider purchasing a portable electric fence.

If you want to see bears but don’t know anything about them, hire a guide. You have no business trying to get close to a bear on your own if you have no bear experience.

One of my favorite parts of Bertie’s article is where he uses an illustration to demonstrate the likelihood of being killed by a bear. As the graphic clearly shows, you are much more likely to be killed by a dog, a cow, or lightning than you are to be mauled and killed by a bear.

The bottom line if you encounter a bear in the woods: respect the bear’s intelligence and strength, but don’t fear the animal. The bear is likely more terrified of an encounter with you than you are of seeing him.


Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. Sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska, and listen to her podcast, Murder and Mystery in the Last Frontier.

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Why are Gray Whales Dying?

One-hundred-seventy-one gray whales have washed up on Pacific beaches from Mexico to Alaska so far this year. Seventy-eight whales were spotted off the coast of Mexico, 85 in U.S. waters, and eight near Canada. Of the whales found along the U.S. Pacific Coast, 37 dead whales were spotted in California, five in Oregon, 29 in Washington, and 14 in Alaska. Since most whales sink to the ocean floor when they die, the 171 recovered carcasses probably represent only a fraction of the number of gray whales that have died on their northward migration this spring and summer.

In my last post, I wrote about tufted puffins dying on the Pribilof Islands in the Bering Sea, and I explained how their deaths are likely linked to the warming ocean temperatures in the Bering Sea. It comes as no surprise to learn puffins aren’t the only animals affected by warming water temperatures and melting sea ice. From the smallest zooplankton to the most massive whales, all animals in the region are feeling the impact of climate change.

Gray whales have one of the longest migrations of any mammal.  In the summer they feed in the Arctic in the Bering, Chukchi, and Beaufort Seas, and in the fall, they migrate to their calving grounds in the southern Gulf of California and Baja Mexico, a migration of 5000 to 7000 miles (8,050 – 11,275 km) each way.  Their average swimming speed is only 3 to 5 mph (5-8 km/hr), so this migration takes a long time.

NOAA

The known deaths of 171 whales have induced the National Oceanic and Atmospheric Administration (NOAA) to declare an “unusual mortality event” and launch an investigation to determine why the whales are dying. Necropsies of the whales indicate most have starved to death. Ship strikes killed four found in San Francisco Bay, and since gray whales don’t usually enter this area, researchers assume these animals were stressed and perhaps searching for food.

Investigators aren’t sure why the whales are starving, but they think it’s possible the gray whale population has exceeded its carrying capacity under current conditions. In other words, there are too many gray whales and not enough food.

We know gray whales have been impacted by ocean warming in recent years.  During the summer of 2018, waters in the Bering Sea soared nine degrees warmer than average. These increasing seawater temperatures have reduced winter ice cover in the region, which has led to a reduction in productivity.  Primary productivity in the northern Bering Sea declined 70% from 1988 to 2004. This previously ice-dominated, shallow ecosystem favored large communities of benthic amphipods (the favorite food of gray whales), but it has now been replaced by an ecosystem dominated by smaller species of zooplankton, such as krill. Gray whales have responded by migrating further north to the Chukchi Sea, but amphipods might now be disappearing from this region as well, forcing gray whales to consume less nutritious krill, and krill might not contain the percentage of fatty acids the whales need to build adequate blubber.

Scientists expect to find more dead gray whales this summer, and one was recently washed up on a beach on Kodiak Island. NOAA continues to monitor the mortality event and posts updates on this website.


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Robin Barefield is the author of three Alaska wilderness mystery novels, Big Game, Murder Over Kodiak, and The Fisherman’s Daughter. To download a free copy of one of her novels, watch her webinar about how she became an author and why she writes Alaska wilderness mysteries. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.

Mystery Newsletter

Sign Up for my free, monthly Mystery Newsletter about true crime in Alaska.