Tag Archives: Pacific Herring

Commercial Herring Fishery in Alaska

May 26, 2019Fish, Kodiak WildlifeCommercial Herring Fishing, Herring, Herring Fishing in Alaska, Pacific Herring, Sac Roe Herring Fishery, Spawn-on-Kelp Herring Harvestadmin

Herring are valuable fish to commercial fishermen, and in Alaska, herring are mainly harvested for their eggs which are shipped to Japan.

In last week’s post, I wrote about the biology and life history of the Pacific herring, and I explained how important herring are to the diets of many birds, fish, and marine mammals, but herring is also a valuable commodity to humans. For hundreds of years, Alaska native populations have conducted subsistence fisheries for herring. In the spring, villagers from coastal communities harvested herring eggs on kelp or hemlock boughs, and traditional dried herring is still an important resource in Bering Sea villages near Nelson Island where salmon is not readily available.

The commercial herring fishery in Alaska began in 1878 when 30,000 lbs. were caught for human consumption. Early Alaskan settlers preserved herring by salting the fish and storing it in large, wooden barrels. Salted and pickled herring production peaked after WWI when 28 million pounds (12,700 mt) were produced annually.

Reduction fisheries, which are the production of fish oil and fish meal from ground-up fish, began in Southeast Alaska in Chatham Straight in 1882. Reduced herring became more popular in the 1920s, and reduction plants sprang up from Craig to Kodiak in areas with large herring stocks. Harvests during the 1920s and 1930s reached 250 million pounds (113,400 mt) per year, and herring stocks declined in response to this unsustainable harvest. During the 1950s, the low cost of reduced Peruvian anchovies caused the reduction market in Alaska to collapse, and the last herring reduction plant in Alaska closed in 1966.

The Alaska sac roe fishery for herring began in the 1970s when the demand for imported herring eggs in Japan increased after Japan’s herring fishery declined. The sac roe fishery targets female herring just before they spawn. Pre-spawn egg sacs are removed from the female herring and shipped to Asia where they are a highly prized delicacy called kazunoko. Most herring for this fishery are caught by purse seining with a smaller percentage caught by gill netting. Unlike any other fishery in Alaska, managers carefully monitor the quality of the herring during the fishery to obtain the highest-value product possible. Technicians periodically test the condition of the female herring as their eggs ripen, and fishery managers use this information to carefully time the opening of the fishery to within days or even hours before the females are ready to release their eggs. This scrutiny ensures the eggs are ripe and prime for the Japanese market.

Most herring fisheries in Alaska are regulated as management units or regulatory stocks, and these stocks are very specific, often to small geographical areas. While managers might open herring fishing in one bay, the fishery could be closed in an adjacent bay because the herring return to spawn in the second bay the previous year did not meet sustainable levels. The herring sac roe fishery is competitive and intense. Fishery managers often open fishing at noon and close it a few hours later when fishermen have reached the quota for the area. Herring purse seiners work together in groups called combines and hire spotter planes to search for large schools of herring. The purse seine boats stand by near a school of herring until managers declare the fishery open, and then they quickly deploy their nets to scoop up the fish.

Since fishermen are only after the eggs in a sac roe fishery, the carcasses of the females and males caught in the nets are either processed for fishmeal or are sold for bait to commercial and sport anglers. There also is still a smaller food and bait fishery for herring.

In addition to the sac roe fishery, there is another type of commercial harvest for herring eggs called a spawn-on-kelp harvest using floating pens. Herring are caught with purse seines and then confined in floating pens containing kelp. When the herring spawn, the eggs attach to the kelp and are harvested. The eggs from this type of fishery sell for a very high value.

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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Pacific Herring (Clupea pallasii)

May 19, 2019Fish, Kodiak WildlifeAlaska Herring, Clupea pallasii, Herring biology, Herring on Kodiak Island, Kodiak Alaska, Pacific Herringadmin

Last week, I mentioned how the Pacific herring (Clupea pallasii) had returned to Uyak Bay on Kodiak Island this spring in such large numbers, even bears recently out of hibernation noticed and were feeding on them in the shallow estuaries where they spawn. Pacific herring are an essential food source for many animals living in or near the North Pacific, including birds such as cormorants, murres, auklets, puffins, and bald eagles; fish, such as salmon, halibut, cod, and pollock, and marine mammals, including harbor seals, Steller Sea Lions, fin whales, humpback whales, and orcas. When a pursuing predator forces a school of herring to the surface, seagulls take advantage of the situation and can often be spotted noisily diving and feeding on the fish. Herring are loaded with nutritious oil and nutrients and are an important forage fish for many species.

A herring has a blue-green upper body, silvery sides, and large eyes. Its body is laterally compressed with large scales, protruding in a serrated fashion. It has no scales on its head or gills. A herring has a deeply forked tail, a single dorsal fin located mid-body, and no adipose fin. Pacific herring can grow to 18 inches (45.7 cm) in length, but they are usually smaller than 9 inches (22.9 cm).

Pacific herring live throughout the coastal waters of the Pacific Ocean. In the eastern North Pacific, they range from Baja California north to the Beaufort Sea, and in the western North Pacific, they can be found in the western Bering Sea to Kamchatka, in the Okhotsk Sea and around Hokkaido, Japan southeast to the Yellow Sea.

^[Pacific herring reach sexual maturity when they are three to four years old, and they spawn each year after reaching sexual maturity. Spawning occurs in the spring in shallow nearshore areas in intertidal and subtidal zones. Females release eggs at the same time males release sperm into the water, and the eggs and sperm mix, fertilizing the eggs. A single female can lay 20,000 eggs.

Spawning is precise, and while the trigger is not well understood, researchers suggest the male initiates the process by releasing milt containing a pheromone which stimulates females to release eggs. The process seems to be synchronized, and an entire school spawns in a period of a few hours, producing an egg density of up to 6,000,000 eggs per square yard (square meter).The fertilized eggs then attach to vegetation such as eelgrass or kelp or to the bottom. Eggs hatch two weeks after they are fertilized, and the larvae drift in the ocean currents. As they grow, juvenile herring stay in sheltered bays until autumn and then move into deeper water where they spend the next two to three years. Juveniles remain separate from the adult population. Biologists estimate only one herring per ten thousand eggs reaches adulthood.

Juvenile herring feed on phytoplankton and zooplankton, and adults also eat bigger crustaceans and small fish. Pacific herring travel in large schools. They migrate inshore to the heads of shallow coves and bays to spawn and then offshore to feed. They also migrate vertically in response to their prey, remaining near the bottom during the day and rising toward the top of the water column at night.

Herring are susceptible to environmental changes. Since they depend on shallow, inshore habitats to reproduce, they are affected by storms, pollution, and warming water temperatures. The Pacific herring population in Prince William Sound collapsed in 1993, four years after the Exxon Valdez oil spill, and it has still not recovered.^[

The biggest threat to Pacific herring is a loss of their spawning grounds. Spawning habitat can be degraded or destroyed by construction, dredging, log storage, oil spills or other pollution, and by global warming.^[ If Pacific herring populations crash, their loss will affect the many species of fish, birds, and marine mammals which depend on them for food.

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Spring on Kodiak Island

May 12, 2019Fish, Kodiak Bear, Kodiak WildlifeKodiak Bear, Kodiak Island, Pacific Herring, Robin Barefield, What Do Bears atadmin

I love spring. It is my favorite season. As winter loosens its grip and the vegetation begins to grow again, the world seems to return to life. Foxes scream in the middle of the night in search of new mates; does arrive in our yard with their wobbly, newborn fawns; eagles soar in mating spirals and begin remodeling their nests for the arrival of their chicks; and bears leave their dens in search of food after a long winter of fasting.

Spring always brings unexpected joys, and no two springs are alike. This year, we have watched an abundance of herring enter Uyak Bay to spawn. Often when large schools of herring return, we see increased whale, seal, and sea lion activity in the bay, but this year we’ve observed something different and exciting. Bears are feeding on the herring in the tidal flats at the head of Uyak Bay where the herring spawn. While in the summer months, bears typically catch and eat salmon in this same area, they don’t usually congregate to feed on herring. Herring are rich, oily fish loaded with nutritional value, and they provide a great supplement to a bear’s diet.

Bears’ stomachs contract during hibernation, and when they first leave their dens, their appetites are suppressed, and they eat little, concentrating on emerging plants and their roots. As spring progresses, bears can be seen feeding in grassy meadows and look much like grazing cattle with their heads bent to the earth. We don’t usually see bears feeding on fish until summer when they chase and catch salmon, but bears are opportunistic feeders, and since the herring are here now, bears are taking advantage of their abundance.

Herring are smaller than salmon, making them more difficult for a bear to catch. The herring swim into the eelgrass in the tidal areas at the head of Uyak Bay where they lay their eggs. When the tide ebbs, the fish temporarily become stranded in the shallow tidal pools, and bears can chase down and pounce on the fish.

As with salmon fishing, older bears are better than younger bears at landing herring. Fishing is a skill bears learn with much practice over time, so young bears are often clumsy fishermen. A sub-adult bear might gallop back and forth for thirty minutes without successfully landing a fish, while an older bear walks deliberately through the water and pounces with little effort on a passing herring. Each bear develops his own, unique fishing technique.

In the long run, this early appetizer of herring probably will make little difference to the overall health of the bears, but if Kodiak has a poor berry crop and a poor salmon run, this early addition of herring could sustain the bears until the salmon arrive.

Spring is only beginning here on Kodiak Island, and I can’t wait to see what other surprises the season has in store for us.