Robin Barefield's Blog, page 10
July 22, 2018
Pacific Cod Commercial Fishery
Three weeks ago, I wrote about the collapse of the Pacific cod population in central and southwestern Alaska. Over the course of two years, cod went from one of the most prolific fish species in the area to nearly non-existent. The Alaska Department of Fish and Game slashed commercial fishing quotas in 2017, but there were so few cod, commercial fishermen struggled even to catch the allowed poundage. The economic ramifications from the crash of the Pacific cod fishery are just beginning to affect Alaska’s ports, and biologists believe it will be years before the launch of another viable cod fishery.
This week, I’ll explain more about the history of the Pacific cod fishery and commercial methods for harvesting cod in Alaska. First, though, I want to emphasize the importance of Pacific cod not only to fishermen but also to consumers. Most of us at some point in our lives have eaten cod; whether it was a fish stick, a fish sandwich, fried fish, or baked white fish, cod is one of the most popular fish served by restaurants from fast-food drive-ins to diners to gourmet bistros. Cod has a mild flavor and a dense, flaky white flesh. It freezes well and can be shipped long distances. Cod liver oil is made from cod livers and is an important source of vitamin A, vitamin D, vitamin E, and omega-3-fatty acids.
[image error]The Pacific cod fishery gained traction just as the Atlantic cod fishery began to crash. The Atlantic cod fishery lasted for more than 1000 years and was popular even during the Viking period, around 800 AD. The fishery was vital to Europe, Canada, and the U.S., but this widespread popularity of Atlantic cod led to its downfall. Atlantic cod populations survived centuries of human strife, ranging from plagues to wars, only to be fished to the point of annihilation because the many countries that commercially fished cod couldn’t agree on regulations to protect this valuable resource. With Atlantic cod no longer available, fish buyers looked to the Pacific.
Pacific cod have been commercially fished on a small scale since the 19th century, but the modern commercial fishery began in the early 1960s with the Japanese longline fishery in the Bering Sea/ Aleutian Island (BSAI) region. Between 1980 and 1989, a U.S. trawl fishery and several joint venture fisheries began in both the BSAI and the Gulf of Alaska (GOA) regions, and by 1989 the U.S. commercial cod fishery overtook the foreign fishery in both the BSAI and GOA regions.
Multiple methods are now used to harvest Pacific cod, including trawl, longline, pot, and jigging. Between 1991 and 1999, trawl gear accounted for 52% of the cod catch, longline gear took 37% of the harvest, and pot gear caught 11%. After 2000, however, longline fishing became the most productive means of landing cod. Between 2000 and 2006, longline gear accounted for 46% of the catch, trawl gear 37%, and pot gear 16%.
[image error]According to recent NOAA Fisheries Service surveys of Pacific cod stocks taken only a few years before the population collapsed, the cod stocks in Alaskan waters were stable and were not being over-fished. In 2010, NOAA estimated the BSAI stock at 1 million metric tons and the GOA stock at 0.4 million tons. Biologists have closely regulated the Pacific cod fishery and have erred on the side of caution by setting strict quotas to protect not only the cod fishery but also marine mammals such as Steller sea lions that depend on cod for food.
Researchers are now working diligently to discover what happened to the Pacific cod. Why did the cod population crash in Alaska? The leading theory is the crash was caused by warmer-than-normal ocean temperatures which in turn caused a reduction in the biomass of phytoplankton and zooplankton in the North Pacific. Juvenile cod, like most young fish, depend on zooplankton as a food source. Because of the reduction of zooplankton in the North Pacific, juvenile cod had little to eat, and many starved to death.
If the zooplankton biomass in the North Pacific has decreased to the point where cod can’t find enough to eat, we should all be concerned, not only for cod but for all animals in this portion of the sea. Marine animals from the smallest fish and birds to the largest whales depend on phytoplankton and zooplankton to survive.
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[image error]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. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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The post Pacific Cod Commercial Fishery appeared first on Robin Barefield.
July 15, 2018
Pacific Cod (Gadus macrocephalus)
True cod belong to the genus Gadus. The two most common members of the genus Gadus are the Atlantic cod (Gadus morhua) and the Pacific cod (Gadus macrocephalus). These two species are similar in appearance, reproductive biology, and lifecycles. Pacific cod are also known as grey cod, gray cod, greyfish, or grayfish.
Pacific cod range from Japan to the Bering Strait and the Gulf of Alaska and south as far as Northern California. Pacific cod are bottom dwellers and are usually found between depths of 40 to 1800 ft. (12-549 m). They tend to move into deeper water in the fall and winter.
A Pacific cod’s body is elongate and ranges in color from grey to brown on the back and sides to a pale cream on the stomach. Mottled spots or pale areas cover the backs and sides. A cod has a triangular tail, three rounded dorsal fins, and two anal fins. The fins are dusky colored and have white edges. The upper jaw of a cod extends over the lower jaw, and it is easy to identify a Pacific cod by its single chin barbel, or whisker, that has a length nearly equal to its eye diameter. Female cod can grow to 58 inches (147 cm) in length and weigh 55 lbs. (25 kg) Males are slightly smaller and can reach a length of 55 inches (141 cm) and weigh 44 lbs. (20 kg).
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Female cod reach sexual maturity when they are four to five years old at a length of 20 to 23 inches (50-58 cm). In Alaska, most spawning activity occurs in March. Males court females by displaying their fins and grunting. A male and female then pair, and the male swims upside down under the female while she releases her eggs and he releases his sperm. The fertilized eggs then sink to the bottom where they remain for eight to 23 days before the hatch. A newly-hatched cod enters a planktonic phase for the next ten weeks while its body weight increases by 40-fold. When it is approximately 0.79 inches (2 cm) the cod moves to the sea floor and begins eating benthic crustaceans, such as isopods and small crabs. After six months, the cod is approximately 3.1 inches (8 cm) long, and by the end of the first year, it has attained a length of 5.5 – 7.1 inches (14-18 cm). Small cod eat mostly invertebrates, while larger Pacific cod feed on invertebrates and fish.
Cod live a maximum of 18 years. They are plagued by parasites, including the cod worm, Lernaeocera branchialis. Cod worms have a complex lifecycle. They begin as free-swimming larvae but then hook to the front of a flatfish or a lumpsucker. The worms penetrate the flesh of the fish with a fine filament and suck the blood of their host. The worms then mate, and the female worm finds a cod and clings to the cod’s gills, where it then penetrates the body of the cod and enters its heart. The front part of the worm forms branches and burrows into the main artery of the cod and extracts nutrients for itself and its eggs from the cod’s blood. Other parasites also infect cod, and anglers commonly catch cod covered by sores.
Cod are important food fish for larger fish, sharks, and marine mammals, including the endangered Stellar sea lion. They are also a commercially valuable food fish for humans.
Next week, I’ll write more about the importance of cod as a commercial species, and I’ll discuss the various methods of harvesting them.
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[image error]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. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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The post Pacific Cod (Gadus macrocephalus) appeared first on Robin Barefield.
July 8, 2018
What is a Cod?
Four species of fish in the Gulf of Alaska have the common name “cod,” but only two of these species, the tomcod and Pacific grey cod, are true cod. Common fish names are often misleading and confusing. For example, brown trout (Salmo trutta) belong to the genus Salmo, while cutthroat trout (Oncorhynchus clarki) and rainbow trout (Oncorhynchus mykiss) are in the genus Oncorhynchus. To confuse the issue even more, brook trout (Salvelinus fontinalis), lake trout (Salvelinus namaycush), and Dolly Varden trout (Salvelinus malma) are char, not trout. Also, in the southern United States, bullheads are catfish, while in Alaska, we call sculpins bullheads.
True Cod and Imposter Cod
[image error]Lingcod
Lingcod (Ophiodon elongatus) and black cod (Anoplopoma fimbria) are not only unrelatedto Pacific grey cod (Gadus macrocephalus) and Pacific tomcod (Microgadus proximus), but they look quite different from the two “true” cod species. Pollock (Gadus chalcogrammus), though, a species closely related to a Pacific grey cod, isn’t even referred to as a cod. With these confusing common names, we can forgive an angler for not knowing whether he has caught a “true cod” or some unrelated fish.
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Last week, I wrote about the crash of the Pacific cod population in the Gulf of Alaska. In that post, I was discussing only Pacific grey cod. Over the next few weeks, I’ll write posts about the true cod species as well as the cod imposters in Alaskan waters. I hope to clear up any confusion surrounding cod and their common names.
Pacific Tomcod
[image error]Tomcod
The Pacific tomcod (Microgadus proximus) is one of the smaller members of the cod family, reaching a maximum size of 12 inches (30.5 cm). Its body is slender and covered with small, thin scales, but it feels smooth to the touch. It ranges in color from olive green to brown on its dorsal surface and creamy white on its ventral surface. Like its cousin the grey cod, a tomcod has a barbel on its chin, three dorsal fins, two anal fins, a large head, and a large mouth with small teeth. A tomcod’s barbel is smaller than a Pacific grey cod’s barbel, and unlike a Pacific cod, a tomcod’s dorsal fins do not contain spines. Despite these differences, a tomcod looks very much like a small Pacific grey cod.
Tomcod range from central California to western Alaska and can be found anywhere from the surface to as deep as 700 feet. They feed on zooplankton, shrimp, worms, and small fish and in turn, are a food source for larger fish, seals, and sea lions. Because of their small size, tomcod are not an important species for either commercial or sport fishermen, but they are a good food fish and have a sweet, subtle flavor.
Next week, I’ll discuss grey cod. I have already posted about their declining numbers in Alaskan waters, but I’ll delve more into their biology, importance in the ecosystem, and their value as a human food source. The following week, I’ll point out the differences between Pacific and Atlantic cod.
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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. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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The post What is a Cod? appeared first on Robin Barefield.
July 1, 2018
What Happened to the Pacific Grey Cod?
In October 2017, the National Oceanic and Atmospheric Administration (NOAA) made a shocking announcement. Pacific cod (or grey cod) stocks in the Gulf of Alaska had declined 71% since 2015 and 83% since 2013. Cod, once one of the most plentiful fish in Alaskan waters, suddenly became a rare catch, devastating one of the most lucrative commercial fisheries in the state. Biologists scrambled to learn why cod were dying and why the few cod caught weighed less than normal and appeared malnourished.
While researchers yet do not have empirical evidence to support their theory, they have a good idea why cod populations have crashed. During the winter of 2013/2014, scientists mapped an unusually warm, large, circular body of seawater in the North Pacific Ocean. This mass of water didn’t cool as winter progressed but instead hovered several degrees above the normal winter temperature. Scientists nicknamed the mass of warm water the “Blob.” In February 2014, the Blob remained 4.5° F (2.5°C) warmer than the average February ocean temperature.
Warm water temperatures persisted throughout 2014, and oceanographers noted these were the warmest temperatures ever measured in the North Pacific Ocean since climatologists began recording ocean temperatures. Along with these warm water temperatures, a static high-pressure region in the atmosphere persisted throughout much of 2014, resulting in a lack of the normal wind-generated currents that stir the surface waters of the North Pacific.
[image error]The Blob
This warm, calm mass of water produced far-reaching effects on the biology of the North Pacific. Without an upwelling of cooler water and nutrients, the surface waters of the warm Blob became stagnant, resulting in reduced phytoplankton production. Phytoplankton is the platform for the ocean food pyramid, and without a healthy supply of phytoplankton, the pyramid collapses. Zooplankton can’t survive unless they have phytoplankton to eat, and without zooplankton, many fish species, including the juveniles of most species, will starve. Plankton-eating fish provide the food supply for larger fish, and all fish, mammals, and birds dependent on marine life to survive will suffer from a reduction in phytoplankton productivity.
A lack of food was not the only problem Pacific cod faced, though. The increased ocean temperatures raised their metabolism while reducing the available food. With less food, the average size of the cod dropped. A 2015 NOAA survey showed cod were the skinniest ever recorded, and at this same time, mortality rates skyrocketed for the younger age classes of cod, an indication the cod population would not recover for many years. The warm water and lack of nutrients also negatively affected cod egg production.
Will the Pacific grey cod recover? Biologists don’t know the answer to this question, but even if cod populations begin to recover now, they will not be commercially viable until at least 2021. The crash of the cod fishery has had a negative impact on the economies of Alaska fishing ports, and the decline of cod is certain to impact the food web of the North Pacific.
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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. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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The post What Happened to the Pacific Grey Cod? appeared first on Robin Barefield.
June 24, 2018
Chalky vs. Mushy Halibut
[image error]How much does a pound of halibut cost in your neighborhood grocery store? If you can even find halibut for sale, it probably costs more than $20 per pound, and if you decided to buy it, you expect your butcher to hand you a perfect chunk of pristine, white fish. Pacific halibut is one of the most sought-after food fish in the world. When cooked, halibut has a subtle flavor and a flaky texture, but when fishermen report catching halibut with sub-prime flesh conditions, the news alarms sport and commercial fishermen, fish processors, chefs, and consumers. Chalky and mushy flesh conditions are the two biggest concerns for halibut caught in Alaska.
What is the difference between chalky and mushy halibut, and can a human safely eat the meat of a fish afflicted with either condition? The two flesh conditions might both look unappetizing, but they are very different from each other. One is caused by the rigors of an athlete trying to stay in the ocean and out of your boat, while the other is a sign of a malnourished fish. Let me explain in more detail.
Chalky Halibut
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When an animal exerts itself, it uses oxygen to break down glucose and produce energy. During intense exercise, such as when a sprinter runs a race, he might not be able to breathe enough oxygen to complete the chemical process to produce energy. When the body does not have sufficient oxygen, it produces lactic acid, which your body can convert anaerobically (without oxygen) into energy. Producing anaerobic energy works great in the short term, but during prolonged physical exertion, lactic acid can build up in the bloodstream and muscles faster than the animal can burn it, lowering the pH of the muscle tissue.
The blood and muscles of a healthy athlete, as well as those of a healthy fish, will slowly dump excess lactic acid once the athlete or fish stops exerting and begins breathing normally again. When a fish is killed at the end of a long fight, though, the excess lactic acid stays in its flesh. Small halibut in the 10 lb. to 15 lb. range, caught during the warmest part of the summer, are the most susceptible to excess lactic acid in their tissues.
The meat from a halibut with a build-up of lactic acid often looks white and cooked as soon as you fillet the fish, but it sometimes takes several hours before the flesh turns chalky. Instead of the semi-translucent appearance of normal halibut meat, chalky halibut is white and opaque. Chalky halibut looks like raw halibut after the meat has marinated in lemon juice for several hours. Chalky halibut is safe to eat, but the meat often tastes tough and dry when cooked.
Mushy Halibut Syndrome
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As the name implies, halibut with this syndrome have large sections of flesh which are soft instead of firm, and sometimes the flesh is so mushy, it feels like jelly. A mushy halibut is often obvious even before you fillet it because the fish looks emaciated, and indeed, biologists think malnourishment causes this condition.
Mushy halibut syndrome is most prevalent in halibut in the 15-20-lb. range. Although fish pathologists have yet to pinpoint the cause of this condition, they have not found parasites or infectious agents in affected fish, and they do not believe it is a disease that can be transmitted from fish to fish. Microscopic examination of the tissues of mushy halibut reveal a severe loss of muscle mass, and the affected muscles resemble those of animals known to have nutritional deficiencies of vitamin E and selenium.
The muscle atrophy in mushy halibut causes weakness in the fish and compromises the halibut’s ability to capture prey, leading to further malnutrition and weakness. This syndrome is most common in areas where populations of prey fish have declined, and the stomach contents of mushy halibut show many have consumed small crabs instead of the forage fish they normally eat. Researchers wonder if crab lacks some of the nutrients necessary for halibut to thrive.
Mushy halibut is safe to eat, but when cooked, it falls apart and resembles oatmeal.
According to the International Halibut Commission, neither chalky nor mushy halibut are common, but the prevalence of these conditions varies between years and locations. As the oceans warm, researchers worry these conditions will become more common.
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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. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
The post Chalky vs. Mushy Halibut appeared first on Robin Barefield.
June 17, 2018
Sunshine
Ahh, sunshine! Finally, we’ve had a week without clouds. When the sun shines on this lush, green rainforest I call home, no place is more beautiful, and a day of sunshine makes me forget all the cloudy, rainy days preceding it. We have had a cool spring with almost no sunshine until now, and I was beginning to wonder if I would ever see the sun again.
June is “work” month here at our lodge on Kodiak Island. It is the month we paint, fix, clean, and garden in preparation for our summer bear-viewing and sport-fishing trips. A day of sunshine means it is time to rush outdoors, grab a brush and spread paint until exhausted. June is also one of the rainiest, foggiest months on the island, so we cannot afford to squander sunshine on decadent activities such as picnics on the beach or hikes in the woods. Nevertheless, I enjoy the sunshine, and after a week of hard work, I am also looking forward to the forecasted rain in a few days!
This time of year, writing is a luxury, and I have to steal a minute here and there to write a few lines. While my mind bursts with story-telling and promotional ideas, I don’t have time to follow through on them. I recently began publishing my murder newsletters on Medium, an online publishing platform. Here is a link to my first article. While this is the wrong time of year to give myself a new job, I was excited to have an additional outlet for my writing, and I couldn’t wait to see if people would read my stories on Medium. I dreamed of thousands of new readers, but now, I’ll be happy if my article receives a hundred views.
I am eager to get back to writing my next novel. I’m excited about the story, and I love writing fiction. My writing focus this summer, though, will be to finish the edits on my wildlife book. I hope to send it to my publisher this winter.
I have been thinking about my blog posts for this summer, and I plan to focus once again on fish. Of all the posts I have written, my most popular one is, “The Difference Between Atlantic and Pacific Salmon.” I guess this means folks are interested in fish, and since I love talking about fish, it’s a topic I’ll embrace. I have a halibut post planned for next week, and then I’ll jump into the troubling issue of the sudden decline in Pacific grey cod.
[image error]Please send me any questions you have about fish species in the North Pacific, and I will investigate the answer and write a post about it. I will be happy to write about fish biology, fishing regulations, and fishing techniques.
I know I don’t say this often enough, but thank you for reading my posts. I appreciate you! Now, it’s time for me to get outdoors, enjoy this sunshine, and paint something.
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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. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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The post Sunshine appeared first on Robin Barefield.
June 10, 2018
Interesting Facts About Sitka Black-Tailed Deer
While I always smile when I see a Sitka black-tailed deer, I don’t always run for my camera because I see deer nearly every day. Last week, I wrote about the three deer that hang out in our yard. The other day, I stretched out on a sunny spot in the grass and closed my eyes. I felt something touch my face, and when I casually brushed it away, I heard loud breathing and hooves stomping. I sat up abruptly and looked into the eyes of a young buck. I’m not sure which one of us was the most startled, but after we recovered, the deer resumed grazing, and I laughed.
While they may be common, deer are fascinating animals, and I thought I would share a few interesting facts about Sitka black-tailed deer.
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How did deer get to Kodiak Island, and how have they survived?
The most interesting fact about the Sitka black-tailed deer on Kodiak Island is that they exist and thrive here. The deer population on Kodiak stems from a founder population of fewer than 35 animals. Twenty-five Sitka black-tailed deer were introduced to the north end of Kodiak Island in three transplants from 1924 to 1933, and another nine deer were introduced in 1934. The deer population has since spread to most areas of the Kodiak archipelago, and despite the limited gene pool, the population appears to be healthy. The size of the deer population fluctuates from year to year, depending on the harshness of the winter, but biologists estimate when the population is at its peak, approximately 70,000 deer on live on the archipelago.
How can deer eat some poisonous plants?
After a long, cold winter, deer enthusiastically graze on the first green sprouts in the spring, and they often eat skunk cabbage, despite the fact the plant contains oxalic acid, a poisonous compound. Humans who have tasted skunk cabbage claim the plant burns their mouths for hours, but it doesn’t seem to bother deer. Deer are also able to tolerate other toxic plants, and it is possible their gut bacteria can neutralize the toxins in these noxious plants.
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How do deer communicate with each other?
A couple of weeks ago, I wrote about how foxes communicate with each other. One of the ways deer communicate is with the aid of pheromones produced by the scent glands located on the lower legs. A gland on the outside of the lower leg produces an “alarm” scent, a gland on the inside of the hock produces a scent to help deer recognize each other, and glands between the toes leave a scent trail when a deer walks. Deer have excellent senses of sight, smell, and hearing. Their ears move independently of each other, allowing them to pick up on signs of danger from different directions.
Why do some deer have deformed antlers?
A certain percentage of deformed antlers are common in any deer population and may be produced as the result of an injury. Research shows that leg, pedicle, and velvet injuries can all lead to deformed antlers, and these deformities may be temporary or permanent. Some deer in certain areas of Kodiak Island, particularly the Aliulik and Hepburn Peninsulas on the southern end of the island, display abnormal antlers with a bizarre shape, sharp tips, and retention of velvet well into the mating season. Research on these deer indicates they are also sterile. At first, the problem was believed to be genetically linked due to the narrow gene pool of the small founder population. This theory, however, did not explain why the deer with the mutated antlers were mostly concentrated in one area of the island, even though there was nothing confining the deer to this area. A study published in 2005 carefully analyzed all aspects of the problem and concluded the sterile deer with the malformed antlers were not the result of inbreeding. Instead, researchers think the deer living in this area of the island are ingesting something such as kelp or grass laced with estrogenic molecules that alter antler growth, transform testicular cells, and block the descent of fetal testes.
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The Sitka black-tailed deer on Kodiak Island experience the best and worst of nature. In the spring and summer, they enjoy an endless supply of food in this lush environment, but winters are often harsh, and nearly the entire deer population can be wiped out by a series of cold, snowy winters.
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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. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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The post Interesting Facts About Sitka Black-Tailed Deer appeared first on Robin Barefield.
June 3, 2018
How do Deer Antlers Grow?
Why do deer have antlers, and how do they grow so fast? Can you imagine having to walk around with a set of antlers on your head? I get a headache just thinking about it.
Last year in late May, we saw a Sitka black-tailed deer doe with two newborn fawns in our yard. They took up residence nearby, and we still see the trio nearly every day as they graze on our sprouting grass. The fawns are now almost the same size as the doe, and I wonder when they will wander off on their own. Will the doe have a new set of fawns this year? She doesn’t look pregnant, but we will know for certain in a few weeks.[image error]
Does between the ages of five and ten are in their prime and usually produce two fawns a year. Mating season on Kodiak occurs between mid-October and late November. The gestation period is six to seven months, so fawns are born from late May through June. Twins are the most common, although many young does only produce a single fawn, and triplets do sometimes occur. Newborn fawns weigh between 6.0 and 8.8 lbs. (2.7 to 4.0 kgs.). For the first week, a newborn fawn has no scent, allowing the mother to leave the fawn hidden as she browses for food to rebuild her energy reserves after giving birth.
The two young deer we often see in our yard are bucks, and they have little nubs on their heads. Bucks begin to grow a new set of antlers in the late spring because the increased daylight in the spring stimulates the hormones that regulate antler growth. During the spring and summer, antlers receive a rich supply of blood and are covered by a fine membrane called “velvet.” At this time, the antlers are fragile and vulnerable to cuts and bruises. By August, antler growth slows, and they begin to harden. A few weeks later, antler growth ceases, blood flow to the antlers stops, and the velvet dries up and falls off. Bucks then retain these hard, polished antlers throughout the mating season. After the mating season, cells start to de-mineralize the bone between the pedicle and the antler, weakening the connection between the skull and the antler, and the antler falls off. On Kodiak, deer normally begin dropping their antlers from mid-to-late December.[image error]
Sitka black-tailed deer antlers are fairly small compared to other species of deer and typically have three or four points on either side, including the eye guards. A very large buck might have five points on each side, including the eye guards.
Deer antlers grow at an amazing rate. Biologists have determined white-tailed deer antlers can grow as much as one-half an inch (1.27 cm) per day during their peak growth. Antler size is dependent on age, nutrition, and genetics. Antlers are made from bone, and they develop from the pedicle on the frontal bone of the skull. Male fawns produce “button” antlers at the age of four to five months, and they begin growing their first noticeable antlers the following year. A young buck’s first antlers may be only single spikes, but antler size usually increases with age until they reach a maximum size. Antler growth requires a great deal of energy, so antler size is dependent on good nutrition and environmental conditions. A buck may produce smaller antlers the year following an extremely harsh winter.[image error]
While biologists don’t know why bucks grow antlers, several theories have been proposed:
(1) A buck with large antlers may signal to a potential mate that he is healthy and possess good genes.
(2) Antlers may be used as a weapon during the breeding season to establish dominance between males.
(3) The size of the antlers alone may display age-related dominance without the males having to fight. Although, current research does not support this theory.
(4) Deer may use antlers
to defend themselves against predators. Although, this would only be beneficial for bucks since does don’t have antlers.
It is likely a combination of two or more of these theories point to the true purpose of antlers.
The Kodiak winter of 2016/2017 was very harsh, and biologists estimated as much as 80% of the deer population on the island died. We saw deer carcasses everywhere we hiked in the late winter of 2017. The 2017/2018 winter was mild, and the deer fared much better. The deer wandering through our yard this spring look fat and healthy, and I suspect we will see a bumper crop of fawns this summer.
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Next week, I’ll cover some interesting facts about deer.
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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. If you like audiobooks, check out her audiobook version of Murder Over Kodiak. Also, sign up below to subscribe to her free, monthly newsletter on true murder and mystery in Alaska.
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The post How do Deer Antlers Grow? appeared first on Robin Barefield.
May 27, 2018
How Do Red Foxes Communicate?
You only need to hear the scream of a fox in the middle of the night to know foxes communicate with each other and with other animals. Like dogs, red foxes communicate through body language, vocalizations, and scent.
Most body posturing is either aggressive/dominant or fearful/submissive. A curious fox will rotate his ears while sniffing, and when playing, a fox might perk up his ears and rise on his hind legs. When afraid, red foxes grin in submission, arch their backs, curve their bodies, crouch their legs, point their ears backward and pressed against their skulls, and swing their tails back and forth. Submissive foxes maintain a lower posture when approaching a dominant fox. When two evenly- matched foxes square off, they approach each other sideways and display postures suggesting a mixture of fear and aggression, with ears pulled back, tails lashing, and backs arched. When attacking each other, a red fox approaches its opponent head-on instead of sideways. They hold their tails aloft and rotate their ears to the sides.
[image error]In addition to body language, red foxes use vocalization to communicate. They have a wide vocal range and produce sounds spanning five octaves. Biologists have divided most of these sounds into contact calls and interaction calls. Contact calls are used when two foxes approach each other or when adults greet their kits. Foxes use interaction calls either during courting or when dominant and submissive foxes interact or during an aggressive encounter. A call that does not fit into either of these categories is a long, monosyllabic “waaaaah” sound made during the mating season, and biologists think this vocalization is a female calling for males.
The red fox has extremely good hearing, and unlike other mammals, it can hear low-frequency sounds well, allowing it to detect small animals moving underground, so it can dig the prey out of the dirt or snow. Although not as acute as its hearing, the red fox has a good sense of smell and binocular vision that reacts mainly to movement.
A fox’s sense of smell allows it to use scent to communicate. A fox urinates to mark its territory and food caches. A male raises one hind leg and sprays urine in front of him, while a female squats and sprays urine between her hind legs. Then, anal and supra-caudal glands, as well as glands around the lips, jaws, and on the pads of the feet, aid another fox in detecting the scents marking the first fox’s territory or food cache.
As with most mammals, foxes have developed an elaborate array of means to communicate with each other. Just because we don’t understand their language, doesn’t mean they don’t have one.
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For those of you who enjoy audio books, the audio version of my novel Murder Over Kodiak is now available. Check it out here. Also, you can download a freed digital version of one of my novels by watching my webinar about how I became an author and where I get my ideas for my novels.
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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 NewsletterSign Up for my free, monthly Mystery Newsletter about true crime in Alaska.
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The post How Do Red Foxes Communicate? appeared first on Robin Barefield.
May 20, 2018
The Kodiak Red Fox
The red fox (Vulpes vulpes) is a member of the Order Carnivora and the dog family Canidae. Red foxes occupy the largest geographic range of any member of the Carnivora, across the entire Northern hemisphere, Central America, and Asia. There are currently 45 recognized subspecies of Vulpes Vulpes, and one of these subspecies is Vulpes vulpes harrimani, the Kodiak red fox.
Red foxes are one of only six mammals native to the Kodiak Archipelago, and like most [image error]other Kodiak mammals, Kodiak red foxes are very large. They have a huge tail, coarse, thick fur on the lower back and tail, and a thick ruff around the neck and shoulders. Most Kodiak red foxes are either cross foxes with a black/brown cross on their back and shoulders, or they are a solid reddish-orange in color. Silver foxes make up a smaller percentage of the population and are striking with black fur, silver-tipped guard hairs, and yellow eyes.
Red foxes breed in February and March in Alaska. Soon after mating, the female will begin preparing a den for the arrival of her kits (babies). She may dig her own den, but often a fox just enlarges the home of a smaller burrowing animal. The litter is born after a gestation period of 51 to 54 days. An average litter consists of four kits, but litters of ten are not uncommon.
The kits open their eyes at eight to ten days after birth and leave the den for the first time at five to six weeks of age. By the time the kits are three months old, they begin to hunt on their own, and the leave their mother when they are seven months old.
In the summer, we see young foxes dart out of their dens, playing, chasing each other, and learning to hunt. Kits are curious and will often sit and watch us as we cruise past them in our boat. Even adult foxes are curious, but as they age, they learn to be wary.
Most red fox populations are considered stable. Red foxes are adaptable, and while they [image error]seem to prefer a wild setting, they can thrive even when living near urban populations.
Humans are fascinated by the beautiful, curious, intelligent red fox, and the red fox has been the subject of many songs, fables, and parables. In certain areas, foxes are trapped or shot for their furs, and in the early 1900s, fox farms, to supply pelts, were established on many of the small islands around the Kodiak Archipelago and off the Alaska Peninsula.
In addition to man, red foxes have several other natural enemies, including wolves coyotes, lynx, wolverines, and possibly bears. Eagles may prey on young foxes. The mite Sarcoptes scabiei causes mange in red foxes, resulting in hair loss, wasting and death. In the wild, red foxes live about five years, but in captivity, they may live as long as fifteen years.
We often see red foxes on the beaches at low tide, feeding on mussels, starfish, sea urchins, worms, and other intertidal animals. Foxes are a part of the Kodiak landscape, and I smile whenever I spot one.
Next week, I’ll tell you how foxes communicate with each other.
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The audiobook of Murder Over Kodiak is now available, and you can buy it here. If you want a free digital copy of one of my books, watch my webinar, and you can download the book for free at the end.
Please leave me a comment if you have any observations, questions, or suggestions
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[image error]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 NewsletterSign Up for my free, monthly Mystery Newsletter about true crime in Alaska.
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The post The Kodiak Red Fox appeared first on Robin Barefield.
