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A new ecology topics posted on 7 December 2022
Site opening on 17 September 2022
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Saury season is finally here. We will provide you with saury information just in time for the season.
The unexpected relationship between saury and Commodore Perry, the challenges of Pacific saury farming, and other topics pique our curiosity. With people saying, "Pacific saury resources are...", I think we should help improve our understanding of the Pacific saury as a living organism. We hope that this website will help to improve on that knowledge.
The welcome photo is a picture of a larvae provided by Associate Professor Nakaya, who was one of the first to engage in basic research on the expanding Pacific saury aquaculture. It is a rare photo of the larvae, only a few days after hatching. They have the body of a ‘child’, with a big head, but the body already has a beautiful form that is typical of Pacific saury.
When I think of saury, the first thing that comes to mind is of it charcoal-grilled on a grill. I remember decades ago, saury was grilled one after another in front of the eaves of the neighborhood fishmonger's shop with a crackling sound and a fragrant aroma. The modern grill has replaced the shichirin, and the analog way of doing things that stimulates the five senses may be one more loss from childhood...
Research, as in the case of grilled saury, will continue to progress as new findings and technologies are discovered. We hope that by learning from the past and looking at the Pacific saury, we will find people who have new ideas and will use the development of new technologies for increasing saury cultivation and more.
FoM Editorial
17 September 2022 posted
Classification of Pacific Saury
Pacific Saury, Cololabis saira, is a fish species belonging to the order Beloniformes. Although Beloniformes also includes needlefishes (Belonidae), flyingfishes (Exocoetidae) and halfbeaks (Hemiramphidae), Pacific Saury is easily separable from these fishes in having both short and beak-like upper and lower jaws, and a small pectoral fin (versus both jaws being long in needlefishes, large pectoral fin in flying fishes, and short upper jaw and long lower jaw in halfbeaks; see Figure for comparison of Pacific Saury and a belonid Thlosurus crocodilus). Other than these characteristics, Pacific Saury has the lower jaw slightly protruding beyond the upper jaw anteriorly, small fins (so called ‘finlets’) posterior to the dorsal and anal fins, and a lateral line situated on the lower portion of the body. Pacific Saury is epipelagic, distributed in the North Pacific from the eastern coast of Korean Peninsula to Baja California, on the western coast of North America. In Japan, it is known from Okhotsk coast of Hokkaido, the Japan Sea and Pacific coasts from Hokkaido to Kyushu, East China Sea, Seto Inland Sea and Yaku-shima Island.
Pacific Saury was described as a new species in 1856, more than 160 years ago. When it was newly described, it was included in the genus Scomberesox, but it is now included in the genus Cololabis established by Gill (1896). The generic name Cololabis was derived from Greek, meaning “shortened scissors” (Nakabo and Hirashima 2015). It is thought that this name is derived from its short upper and lower jaws. The specific name saira was derived from “Saira”, a local Japanese name used in some areas in Japan. Recently the genus Cololabis has included Cololabis adocetus other than C. saira, and a related genus Scomberesox containing 3 species, Scomberesox saurus, Scomberesox scombroides and Scomeresox simulans. These species, except for Pacific Saury, occur in oceans outside of Japan.
Pacific Saury was originally described by James Carson Brevoort. Brevoort described it based on a single specimen collected from Shimoda (as Simoda), Japan. Specimens used for the description of a new species are recognized as “type specimens”. Although type specimens are a standard of a species, and thus they are very important and have scientific value, the whereabouts of this type specimen of Cololabis saira is unknown. However, the drawing of the species presented by Brevoort (1856) shows well-known characteristics of Pacific Saury. The specimen of Pacific Saury examined by Brevoort was collected by Matthew C. Perry, a commodore of the United States Navy, who forced the opening of Japanese ports to international trade. In the second volume of the narrative of the expedition by Perry, Brevort described 10 Japanese new species other than Cololabis saira. Brevoort was a friend of Perry. This might be a reason for the scientific name of Sakhalin Taimen (Hucho perryi), which was derived from the name of Perry (Brevoort 1856).
As mentioned above, because Pacific Saury is easily distinguished from needlefishes, flyingfishes and halfbeaks, it was included in the family Scomberesocidae with the genus Scomberesox (e.g., Collette et al. 1984; Nelson et al. 2016). Recently it has been inferred that Pacific Saury and related species was derived from needlefishes (Lovejoy et al. 2004 as molecular study and Toyama et al. 2020 as morphological study, for example). Accordingly, a new classification, not recognizing the family Scomberesocidae and including Pacific Saury and related species in the family Belonidae with needlefishes, is proposed.
IMAMURA Hisashi・Faculty of Fisheries Sciences, Hokkaido University · Professor / the Fisheries Science Center, the Hokkaido University Museum · Director
Figure Plate including drawing of Pacific Saury presented by Brevoort (1856). From top: Pacific Saury (Cololabis saira), belonid Thlosurus crocodilus (as Belone glgantea), pholid Rhodymenichthys dolichogaster (as Gunnellus dolichogaster) and stichaeid Soldatovia polyactocephala (as Clinus polyactocephala)
References
Aizawa M, Doiuchi R (2013) Scomberesocidae. Pages 667, 1933 in Nakabo T ed. Fishes of Japan with pictorial keys to the species, third edition. Tokai University Press, Hadano (in Japanese).
Brevoort JC (1856) Notes on some figures of Japanese fish taken from recent specimens by the artists of the U. S. Japan Expedition. Pages 253–288, pls 3–12 in Hawks FL ed. Narrative of the Expedition of an American Squadron to the China Seas and Japan, performed in the years 1852, 1853, and 1854 under the command of Commodore M. C. Perry, United States Navy, by order of the Government of the United States. Vol. 2. Beverley Tucker, Washington DC.
Collette BB, McGowen GE, Parin NV, Mito S (1984) Beloniformes: development and relationships. Pages 335–354 in Moser HG, Richards WJ, Cohen DM, Fahay MP, Kendall AW Jr, Richardson SL eds. Ontogeny and systematic of fishes. Allen Press Inc., Kansas, USA.
Fricke R, Eschmeyer WN, Van der Laan R (eds) (2022) Eschmeyer’s Catalogue of Fishes: genera, species, references (http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp) Electronic version accessed 21 July 2022.
Gill TN (1896) The families of synentognathous fishes and their nomenclature. Proc US Nat Mus 18: 167–178.
Lovejoy NR, Iranpour M, Collette BB (2004) Phylogeny and jaw ontogeny of beloniform fishes. Integr Comp Biol 44: 366–377.
Nakabo T, Hirashima Y (2015) Scientific names of Japanese fishes: etymology. Tokai Univ. Press, Hadano.
Nelson JS, Grande TC, Wilson MVH (2016) Fishes of the world, fifth edition. Wiley, New Jersey.
Toyama T, Kawai T, Imamura H (2020) Phylogenetic systematics of the needlefishes (Beloniformes: Belonidae). Thai Nat Hist Mus Jour Monogr 1: 1–73.
17 September 2022 posted
The Ecology of the Pacific Saury
Pacific saury is one of the most common autumnal foods in Japan. In recent years, however, pacific saury is becoming more expensive due to declining catches. Here we describe the ecology of saury and the factors that have contributed to the decline in catch.
Pacific saury is a type of small floating fish that inhabits a wide area of the North Pacific Ocean, and its life span is estimated to be less than two years at the most (typically at the dinner table it is one year old). They spawn at temperatures around 20℃ and forage mainly in waters between 8 and 15℃, migrating on a large scale as they mature. Pacific saury eggs are about 2 mm in size and have about 20 attachment threads (Figure Eggs of Pacific Saury). These attachment threads entangle the fish in floating debris such as algae (Figure 2). The body size at hatching is approximately 8 mm, and although the body shape differs from that of the parent, the back is dark blue and the belly is silver, resembling the parent (see Welcome photo). After hatching in the seas around Japan, pacific saury moves northeastward on the ocean currents and mature in the waters south of the Aleutian Islands (8-15℃) from spring to summer, feeding on the abundant food (mainly zooplankton). In autumn, when the water temperature begins to drop (the 15℃ water temperature zone moves south), larger pacific saury migrate to the waters around Japan. In Japan, pacific saury is caught during this period when the fishing grounds are closer. Thus, pacific saury moves widely around the North Pacific Ocean according to water temperature, and it is believed that the catch in Japan varies according to the timing of the water temperature drop from year to year, and the strength and direction of ocean currents.
NAKAYA Mitsuhiro・Faculty of Fisheries Sciences, Hokkaido University・Associate Professor
Figure Eggs of Pacific Saury.
17 September 2022 posted
Spawning Grounds of Pacific Saury
Pacific saury migrate northward to grow in spring and summer, and then begin their southward migration to mature in autumn, spawning in relatively warm waters from autumn to spring of the following year. Based on studies of the distribution of hatchling larvae immediately after hatching, the spawning grounds of Pacific saury are estimated to be located in the offshore areas east of Honshu Island in spring and fall, and around the Kuroshio Current area south of Honshu Island in winter (Iwahashi et al. 2006). The main spawning season is considered to be winter, when the distribution density of juveniles is at its highest (Watanabe and Lo 1989). However, since it takes more than 10 days from spawning to hatching in Pacific saury, it is thought that the hatchlings are caught some distance from where they are actually spawned and their distribution area is slightly different from their actual spawning grounds. In addition, very severe weather conditions (see below movie from Fisheries Agency HP), make it difficult to conduct surveys. In particular, there was only fragmentary information on spawning grounds in the offshore area east of Honshu in winter, and the overall picture was not known. Therefore, we examined the characteristics of the distribution of parent fish based on the results of fragmentary surveys conducted over the past 22 years to estimate the overall picture of the winter spawning grounds in the main spawning season more accurately.
The results showed that during the winter spawning season, saury are fairly widely distributed from southern Honshu to the offshore area east of Honshu (Fuji et al. 2021). In addition, saury found in waters above 13°C were generally considered to be mature and about to spawn or have already spawned (Figure). The water temperature range of mature saury distribution varied by area, with relatively high water temperatures (16-21°C) in the west (south of Honshu) and low water temperatures (14-16°C) in the east (east of Honshu). Furthermore, proprotion of larger age 1 fish was higher in the west (south of Honshu) than in the east (east of Honshu). These results indicate that the winter spawning grounds of Pacific saury are not only in the Kuroshio region of southern Honshu, which has been relatively easy to survey and for which information was available, but also extend to the offshore region of eastern Honshu. In addition, since the water temperature and age structure of the parent fish on the spawning grounds differed between the east and west, it is expected that the role of the spawning grounds in saury population fluctuations will also differ between the spawning grounds in the east and west. Further investigation and research into the relationship between the ocean environment and saury spawning in the spawning grounds are expected to help shed light on the mystery behind the large fluctuations in saury stocks.
FUJI Taiki・Fisheries Research and Education Agency, Fisheries Resources Institute, Fisheries Stock Assessment Center, Highly Migratory Resources Division・Senior Scientist
Figure Maturity rate (percentage of individuals immediately after or near spawning) of Pacific saury parents at each sampling point during the winter survey (January 1996-January 2017), partially modified from Fuji et al. (2021).
References
Watanabe, Y., & Lo, N.C.H. (1989). Larval production and mortality of Pacific saury, Cololabis saira, in the Northwestern Pacific Ocean. Fish Bull 87,601-613.
Iwahashi, M., Isoda, Y., Ito, S., Oozeki, Y., & Suyama, S. (2006). Estimation of seasonal spawning ground locations and ambient sea surface temperatures for eggs and larvae of Pacific saury (Cololabis saira) in the western North Pacific. Fish Oceanogr 15: 125–138.
7 December 2022 posted
The Potential of Pacific Saury aquaculture
The selection criteria for cultivated species includes demand and high value as a commodity, easy availability of seedlings, easy rearing and rapid growth.
Although pacific saury is one of the most prolific fish species and in high demand, it does not yet have the image of being an expensive foodstuff. Of the fish species often caught commercially such as sardine, horse mackerel, and mackerel that are familiar to Japanese consumers, horse mackerel and mackerel are increasingly being farmed for Sashimi. The recent catch of pacific saury also suggests that there is scope to consider the possibility of aquaculture.
Around 2000, Aquamarine Fukushima (Fukushima Marine Science Museum) began breeding pacific saury as an experiment, and succeeded in raising fish from spawned eggs to adult fish in an aquarium (津崎 2000ab; 津崎 2001ab). Subsequently, the Fisheries Research Agency (now the National Fisheries Research and Education Agency) conducted breeding experiments and documented the growth and maturation process from eggs to maturity (巣山 2013). At a water temperature of 20℃, saury grow to about 25 cm in length and begin spawning about 240 days after hatching (Nakaya et al. 2010a). Thus, although complete rearing technology for pacific saury has already been established, it is still necessary to control the depletion that occurs during the rearing process (photo: pacific saury with a fractured vertebrae due to collision with a tank; tank covered with plastic sheets to reduce collision mortality (Nakaya et al. 2010b) in order to reach the commercial viability. If stocks and catches continue to decline, reared pacific saury may one day be available on the market.
NAKAYA Mitsuhiro・Faculty of Fisheries Sciences, Hokkaido University・Associate Professor
Figure Pacific Saury with bone fractured after crashing into the wall of aquarium.
References
津崎 順 (2000a) サンマの飼育と展示-I. AMFNEWS 2(2): 2-3.
津崎 順. (2000b) サンマの飼育と展示-II. AMFNEWS 2(3): 1-2.
津崎 順 (2001a) サンマの飼育と展示-III. AMFNEWS 3(1): 1-2.
津崎 順 (2001b) サンマの飼育と展示-IV. AMFNEWS 3(2): 1-2.
巣山 哲 (2013) 第7章 飼育下におけるサンマの産卵生態. 水産学シリーズ 175 漁業資源の繁殖特性研究-飼育実験とバイオロギングの活用- （編：栗田 豊・河邊 玲・松山 倫也）恒星社厚生閣．92-106.
17 September 2022 posted
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