When it comes to markets for Alaska herring, size matters, and for that reason odds of a Sitka Sound sac roe herring fishery in 2020 are slim.
Current market conditions demand herring with an average weight of 110 grams, which is typical of an age-5 or age-6 herring, but this year the overall estimated biomass of 166,425 tons is for age-4 herring, with an anticipated average weight of 92 grams, said Aaron Dupuis, assistant area management biologist at Sitka for the Alaska Department of Fish and Game.
This strong year class has in fact been observed all over the Gulf of Alaska, Dupuis said.
The anticipated average weight across all age classes is 97 grams.
The situation is similar to last year, when herring were available to the fishery, but because they did not meet market requirements, no fishery occurred. The last Sitka Sound sac roe herring fishery occurred in 2018.
ADF&G biologists in Sitka plan to continue monitoring the herring stock there. Aerial surveys are to begin in the second week of March and will continue through the end of herring spawning activity, with the R/V Kestrel arriving in mid-March to conduct vessel surveys. Fishery updates and daily herring spawn maps will be produced as the season progresses, and if market conditions change and there is interest in a commercial fishery updates will be announced.
In Togiak, by comparison, where the average size of herring is over 300 grams, preseason polls indicate that only two processors are interested in buying the harvester this year, down from four in previous years.
Changing demographics in Japanese markets, where this herring was in greater demand in decades past, is also a factor in diminishing markets.
Japanese markets for this herring have traditionally focused mainly on an older population and research presented as far back as 2000 note that Japanese consumption of both salted and flavored herring roe had begun to decline.
A paper presented during the annual Lowell Wakefield Symposium in Anchorage in February 2000 cited several factors as contributing to declining demand, including a changing corporate culture resulting in curtailment of company gift-giving, which discouraged or prohibited public officials from accepting gifts from the corporations they regulate, such as high value branded kazunoko gift packs. Kazunoko is salted herring roe that has been marinated in seasoned Dashi, and is part of Osechi Ryori, the traditional Japanese New Year feast. A prized delicacy, Kazunoko symbolizes prosperous family and a wish for many children and grandchildren.
Researchers of the Wakefield Symposium paper from the University of Alaska Sea Grant College program also noted that the younger generation in Japan tended to prefer a more health conscious diet lower in salt. The younger generation also is more convenience-oriented and less patient with the rituals of traditional cooking, their research paper said.
In Sitka meanwhile Lauren Bell, a doctoral student at the University of California Santa Cruz, is doing research funded through a grant from the North Pacific Research Board in Anchorage on how climate change is likely to influence seafood in Prince William Sound, her focus being on how sea water temperatures impact roe, the earliest stage of development in herring.
Bell said she has found that temperature warming had the most dramatic effect, an observation in line with a lot of other research done on other species of fish.
Warming temperatures tend to speed up the rate of development of the herring roe, so that they hatched earlier than they currently, and when they hatch, they are a lot smaller, while their yolk of eggs that they feed off of for energy is a lot bigger, she said. “But they were not able to convert that energy into growth while in the egg stage,” Bell said. “Something is going on metabolically so they can’t break down the food into energy for growth as efficiently at those temperatures. They hatch with big yolk sacs, but are much smaller and they are more vulnerable to predators,” she said.
Bell also looked at the RNA to DNA ratio in herring roe when hatched, and said the roe had a low RNA to DNA ratio, meaning their body condition was worse, that in this scenario the herring roe are not creating the same amount of proteins needed for growth and tissue repair as they would at lower temperatures.
DNA, or deoxyribonucleic acid, is a molecule carrying genetic instructions for development, functioning, growth and reproduction of all known organisms. The role of RNA, or ribonucleic acid, which is present in all living cells, is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins.