We report on a study of the total lipid content (TL) of chum and pink salmon in the Gulf of Alaska in May 1999. Chum and pink salmon were caught by surface trawl net in the Gulf of Alaska during a spring cruise of the F/V Great Pacific. TL was extracted from the muscle of 99 chum and 50 pink salmon by Folch's method using chloroform/methanol and measured gravimetrically. A significant difference in the total lipid content by ocean age was observed in chum salmon. Younger chum salmon (ocean age -. 1 and .2) had lower lipid content than older fish (ocean age -. 3 and .4). Mean TL in pink salmon was 2.6% in females and 2.7% in males. Our results suggest that low lipid content, previously observed in hig-seas salmon during the winter season, is prolonged into the spring in young chum and pink salmon.articl

Carlson, H. Richard

Honma, Hiromi

Kondzela, Christine M.

Murphy, James M.

Myers, Katherine W.

Nomura, Tetsuichi

ノムラ, テツイチ

ホンマ, ヒロミ

本間, 裕美

野村, 哲一

English

Japan Fisheries Research and Education Agency (FRA)  Repository

1999年5月にアラスカ湾で採集されたサケとカラフトマスの筋肉脂質含量言語: English出版者: さけ・ます資源管理センター公開日: 2024-04-05キーワード (Ja): キーワード (En): total lipid content; muscle; chumsalmon; pink salmon; spring; Gulf of Alaska作成者: 野村, 哲一, Myers, Katherine W., Kondzela,Christine M., Murphy, James M., 本間, 裕美, Carlson, H.Richardメールアドレス: 所属: メタデータhttps://fra.repo.nii.ac.jp/records/2001612URLThis work is licensed under a Creative CommonsAttribution 4.0 International License.IntroductionThe quantity of lipid has been used as a bio-chemical index of trophic condition in a variety of contexts for both freshwater and marine fish (No-votony and Beeman 1990). Dietary lipids play an im-portant role in providing energy in carnivorous fish like salmonids due to their limited ability to utilize carbohydrates as an energy source (Watanabe 1982). Although there have been a large number of lipid studies on cultured fish and artificial food (Wil-son 1991), little is known about high-seas salmonid lipid content. Azuma et al. (1998) reported on the growth characteristics of Pacific salmon through ex-amination of triglycerol and protein content, and nu-cleic acid ratios. In our previous paper, lipid content and fatty acids were examined to investigate trophic condition of chum (Oncorhynchus keta) and pink salmon (O. gorbuscha) in the North Pacific Ocean in winter (Nomura et al. 2000). A low lipid content in the muscle and a high percentage of docosahexae-noic acid in fatty acid composition of neutral lipid were observed in chum and pink salmon in winter. Information on the lipid content of salmonids during high-seas migrations is useful to estimate their trophic condition, growth, and survival. In gen-eral, it is supposed that salmonids resume feeding in spring, and lipid content level in the muscle of these fish may be higher than in winter. But there is no previous report of lipid content in high-seas salmo-nids in spring. In this report, we studied lipid con-tent in the white muscle of chum and pink salmon caught in the Gulf of Alaska in the spring of 1999. Materials and MethodsChum and pink salmon were caught by surface Bulletin of the National SalmonResources Center,  No. 4: 13-18December 2001さけ・ます資源管理センター研究報告　第 4 号　13-18 頁2001年 12月RESEARCH NOTEVariation in Lipid Content in the Muscle of Chum and Pink  Salmon in the Gulf of Alaska in May 1999Tetsuichi Nomura*1, Katherine W. Myers*2, Christine M. Kondzela*3,  James M. Murphy*3 , Hiromi Honma*1, and H. Richard Carlson*3*1Research Division, National Salmon Resources Center,  2-2 Nakanoshima, Toyohita-ku, Sapporo 062-0922, Japan. (nomurat@salmon.affrc.go.jp) *2School of Aquatic and Fishery Sciences, University of Washington,  Box 355020, Seattle, WA 98195-5020, USA *3Auke Bay Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service,  11305 Glacier Highway, Juneau, Alaska 9980-8626, USAAbstract. － We report on a study of the total lipid content (TL) of chum and pink salmon in the Gulf of Alaska in May 1999. Chum and pink salmon were caught by surface trawl net in the Gulf of Alaska during a spring cruise of the F/V Great Pacific. TL was extracted from the muscle of 99 chum and 50 pink salmon by Folch's method using chloroform/methanol and measured gravimetrically. A significant difference in the total lipid content by ocean age was observed in chum salmon. Younger chum salmon (ocean age-.1 and .2) had lower lipid content than older fish (ocean age-.3 and .4). Mean TL in pink salmon was 2.6% in females and 2.7% in males. Our results suggest that low lipid content, previously observed in hig-seas salmon during the winter season, is prolonged into the spring in young chum and pink salmon.Key words: total lipid content, muscle, chum salmon, pink salmon, spring, Gulf of Alaska Contribution A No. 24 from the National Salmon   Resources Center.賛 2001 National Salmon Resources Centertrawl net in the Gulf of Alaska during a spring cruise of the F/V Great Pacific (Table 1) (Carlson et al. 1999). Salmon ages were determined by examina-tion of scale patterns. Ocean age was designated by the European method, whereby a dot followed by a number indicates the number of winters in the ocean, for example, an age-.1 salmon spent one win-ter in the ocean. The fork lengths (FL in cm) and weights (BW in g) of the salmon were measured and used to calculate the condition factor (((BW)/(FL)3) × 1,000). The white muscle was sampled from the dorsal muscle directly behind the head, and muscle samples were frozen at -30oC until analyzed. Total lipids (TL) in the white muscle were ex-tracted with chloroform/methanol by the method of Folch et al. (1957) and measured gravimetrically. Lipids were extracted by homogenizing the white muscle (10 g) with 50 ml of methanol and 120 ml of chloroform. The homogenate was filtered through a lipid free paper into glass vessel. The crude extract and water were mixed in a separatory funnel in the proportions 8:4:3 by volume. The lower phase was collected, and solvent was evaporated with rotary evaporator.The resulting values were tested for significant differences using analysis of variance (ANOVA) fol-lowed by Turkey' multiple comparisons test (p<0.05).さけ・ます資源管理センター研報 Bull. Natl. Salmon Resources Center, No. 4, 200114Table 1.  Sampling station, date, location, number of fish sampled by ocean age, and seawater temperature (ST) in the Gulf of Alaska in the spring of 1999. ST*(oC)PinkChumLatitude(N)Longitude(W)DateStation Ocean ageOcean age1543213.1-3.200100054o06'166o38'May  413.2-3.400300053o26'166o43'May  523.300100053o09'166o23'  May  534.0-4.101200052o51'166o07'  May  543.301410050o58'165o00'May  653.4-3.501200049o59'165o00'May  663.901510049o02'164o59'  May  674.7-4.810300047o59'165o00'May  784.940100047o00'165o00'May  795.041220046o54'165o01'May  7105.1-5.5120000046o23'165o00'May  7116.5-6.640110045o00'164o59'May  8126.5-6.700127343o58'164o59'May  8138.1-8.270000042o34'144o59'May 16148.2-8.3200021043o00'144o58'May 16157.8-7.920002043o51'145o00'May 16167.1-7.2120003345o01'145o00'May 17176.720000046o00'145o00'May 17185.1-5.300110050o57'145o00'May 19194.6-4.900030052o54'145o00'May 19204.8-4.900020054o31'144o58'May 20214.7-4.8002111055o00'144o59'May 20225.0-5.200020055o31'144o59'May 20235.3-5.700170056o00'144o59'May 212450530331516Total*ST, Seawater temperature at head rope of trawl net.ResultsChum salmonTL in female and male age-.1 fish was low and increased with increasing ocean age (Table 2, Fig. 1). There was a significant difference in TL between ocean age-.1 and .4 female chum salmon. In female chum salmon, a significant difference in TL was also observed between ocean age-.2 and .4 fish. TL in ocean age-.1 male chum salmon was significantly lower than in ocean age-.3 male fish.A positive relationship between body weight and TL was observed in ocean age-.4 male fish (Fig. 2). There was no significant relationship between body weight and TL in other ages and sexes of fish. A positive relationship between condition factor and TL was observed in ocean age-.2 female, age-.3 male, and age-.4 male fish. There was no significant relationship between condition factor and TL in other ages and sexes fish. Pink salmonAll pink salmon in the samples were ocean age-.1. TL was 2.6% in female and 2.7% in male (Table 2). There was no significant difference in the aver-age of TL between female and male pink salmon (p>0.05). There was a negative correlation (R2=0.176) between body weight and TL in the male fish, and a positive correlation (R2=0.162) between condition factor and TL in male pink salmon (Fig. 3).Nomura et al. －Lipids in spring chum and pink salmon 15Table 2.  Biological parameter and total lipid content of chum and pink salmon caught in the Gulf of Alaska in May 1999 by ocean age. Fig. 1. Total lipid content in the white muscle in chum salmon caught in the Gulf of Alaska in May 1999 by ocean age. Sample sizes are shown in Table 2. Bars are means, and lines are SD.  Letters at the top of each bar summarize the re-sult of Turkey's multiple comparison (ANOVA).  Data points sharing the same letter are not significantly different (p>0.05).Total lipid content (%)Condition factorBody weightFork length (cm)No. of fishSexOcean ageSpecies(g)0.9-2.3*21.4 (0.47)12.31 (0.58)340 (60)30.0 (1.63)*17Female1Chum0.9-1.41.2 (0.96)11.43 (0.96)320 ( 51)30.4 (2.12)9Male1.0-4.11.9 (0.91)10.80 (0.80)640 ( 110)38.9 (1.59)10Female21.3-2.21.6 (0.35)10.41 (0.56)650 ( 54)39.6 (1.69)5Male1.2-10.94.0 (2.08)12.15 (1.06)2,062 (505)54.9 (4.53)22Female30.9-7.43.9 (2.10)11.90 (1.29)2,452 (490)58.8 (3.34)11Male1.4-15.64.9 (3.33)11.97 (1.10)2,290 (271)57.5 (2.18)16Female41.0-6.43.1 (1.80)11.75 (1.42)2,605 (727)60.0 (3.53)14Male2.7-4.23.6 (0.76)10.68 (0.67)2,120 (380)58.2 (3.71)3Female51.1-9.05.1 (5.57)12.31 (1.55)2,950 (1,060)61.6 (4.95)2Male0.8-6.52.6 (1.29)10.22 (0.94)480 (110)35.9 (3.04)15Female1Pink1.1-6.22.7 (1.34)10.36 (1.03)509 (128)36.5 (3.33)35Male*1 mean (SD)*2 rangeDiscussionIn this study, we found a significant difference by ocean age in total lipid content in the white mus-cle of chum salmon caught in the Gulf of Alaska in spring. We conclude that the effect of age must be taken into consideration when examining lipid lev-els in salmon in offshore waters. The average TL content in winter was 1.1% in chum salmon and 1.7% in pink salmon (Nomura et al. 2000). Present results for TL content of ocean age-.1 and .2 chum salmon, and pink salmon in spring were similar to those in winter, indicating that lipid levels had not increased in early spring. Younger chum and pink salmon still had lower lipid levels than older salmon in spring, and the starved condition observed by No-mura et al. (2000) in winter seemed to be continued even in spring in the Gulf of Alaska.Ocean environmental conditions, especially wa-ter temperatures, play an important role in the regu-lation of metabolism in marine fish. Bioenergetic models show that high-seas salmon expend more en-ergy for metabolism at high temperatures than at low temperatures (Davis et al. 1998; Walker et al. 2000). Sea surface temperature (SST) was lower than 4oC at many stations where chum salmon were caught in our study, but the ocean age-.1 and .2 fish were primarily caught at SSTs between 6.5-8.3oC (Table 1). The surface water layers along the survey transects were well-mixed to a depth of a least 100 m (Carlson et al. 1999), so that young salmon would have had to migrate substantial horizontal or vertical distances to find cooler water temperatures. More studies are needed to reveal effects of annual and seasonal variation in ocean conditions on lipid con-tent in young chum and pink salmon.Our results cannot explain the reason for the ob-served low lipid content of young chum salmon in さけ・ます資源管理センター研報 Bull. Natl. Salmon Resources Center, No. 4, 200116Fig. 2. Relationships between total l ipid content in the white muscle of chum salmon and body weight (left) or condition factor (right) by ocean age. Open and close circles indicate fe-male (n=58) and male  (n=41) fish, respectively. The regres-sion lines were drawn with a solid line for female and broken line for male.Fig. 3. Relationship between total lipid content in the white muscle of pink salmon and body weight (upper) or condition factor (lower). Open and close circles indicate female (n=15) and male (n= 35) fish, respectively. The regression lines were drawn with a solid line for female and broken line for male.spring 1999. At the time of capture, most young chum salmon appeared to be actively feeding on a wide variety of zooplankton prey, and percentages of fish with empty stomachs were lower and stom-ach contents weight as a percentage of body weight were higher than in chum salmon samples collected from the same region in July 1999 (Carlson et al. 1999; Myers et al. 2000). During their ocean migra-tions salmon use much energy for movement and control of metabolism. Lipid is an important energy source for fish, and thus low lipid content in young chum salmon indicates that there was not enough in-take of dietary lipid, or that they expended much lipid on growth. A negative correlation between tri- acylglycerol content and RNA:DNA ratio demon-strates that juvenile chum salmon slow down their growth rate to maintain their energy reserve (Azuma et al. 1998). Low lipid content in young chum and pink salmon in spring may have a significant effect on their ocean growth and survival. There are many papers discussing the associa-tion of lipid levels with maturation (Kiessling et al. 1991; Thorpe et al. 1991; Kadri et al. 1996; Shearer and Swanson 2000). We did not evaluate the rela-tionship between maturation and lipid levels in chum salmon, because we judged maturation only by visual examination of gonads. Pooled-years analyses of historical high- seas salmon data (1956-1971) have shown that older, maturing chum salmon tend to be distributed farther to the north than younger, immature chum salmon in the spring North Pacific Ocean (Neave et al. 1976). We observed lit-tle overlap in the distribution of immature and ma-turing chum salmon during our May 1999 survey, and maturing chum salmon, caught in northern areas along the transect, had higher stomach content weights as a percentage of body weight than imma-ture chum salmon, caught in southern areas (Carlson et al. 1999). The lack of overlap in spring high seas distribution of immature and maturing chum salmon may serve to maximize the growth potential of ma-turing fish and minimize intra specific competitive feeding interactions, perhaps at the expense of re-duced growth rates of younger age groups. Further investigation of seasonal changes and annual varia-tion in lipid content of each age and maturity group of chum salmon will be important for understanding their ocean survival, growth, and fecundity. AcknowledgementsThe authors thank the U.S. National Marine Fish-eries Service, Alaska Fisheries Science Center, Auke Bay Laboratory, Juneau for inviting the senior author (T. N.) to participate in the F/V Great Pacific cruise in the spring of 1999. We would like to ex-press our appreciation to the captain, Charles Bron-son, and his crew on board the F/V Great Pacific for their help in collecting samples during our research cruise.ReferencesAzuma T., T. Yada, Y. Ueno, and M. Iwata. 1998. Biochemical approach to assessing growth charac-teristics in salmonids. N. Pac. Anadr. Fish Comm. Bull., 1: 103-111.Carlson, H. R., J. M. Murphy, C. M. Kondzela, K. W. Myers, and T. Nomura. 1999. Survey of salmon in the northeastern Pacific Ocean, May 1999. (NPAFC Doc. 450) Auke Bay Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, NOAA, Juneau, Alaska, USA. 33 p.Davis, N. D., K. W. Myers, and Y. Ishida. 1998. Ca-loric value of high-seas salmon prey organisms and simulated salmon ocean growth and prey con-sumption. N. Pac. Anadr. Fish Comm. Bull., 1: 146-160.Folch, A. J., M. Lees, and G. H. Stanley. 1957. A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem., 226: 497-509.Kadri, S., D. F. Mitchell, N. B. Metcalfe, F. A. Huntingford, and J. E. Thorpe. 1996. Differential patterns of feeding and resource accumulation in maturing and immature Atlantic salmon, Salmo salar. Aquaculture, 142: 245-257.Kiessling, A., T.  A sg○ a rd, T. Storebakken, L. Johans-○son, and K. -H. Kiessling. 1991. Changes in the structure and function of the epaxial muscle of rainbow trout (Oncorhynchus mykiss) in relation to ration and age III. Chemical composition. Aq-uaculture, 93: 373-387.Myers, K. W., R. V. Walker, N. D. Davis, K. Y. Ay-din, S. Y. Hyun, R. W. Hilborn, and R. L. Bur-gner. 2000. Migrations and abundance of salmonids in the North Pacific, 2000. SAFS-UW-Nomura et al. －Lipids in spring chum and pink salmon 170009, School of Aquatic and Fishery Sciences, University of Washington, Seattle. 93 p.Neave, F., I. Yonemori, and R. Bakkala. 1976. Distri-bution and origin of chum salmon in offshore wa-ters of the North Pacific Ocean. Int. N. Pac. Fish. Comm. Bull., 35. 79 p. Nomura, T., S. Urawa, and Y. Ueno. 2000. Varia-tions in muscle lipid content of high-seas chum and pink salmon in winter. N. Pac. Anadr. Fish Comm. Bull., 2: 347-352.Novotony, J. F., and J. W. Beeman. 1990. Use of a fish health condition profile in assessing the health and condition of juvenile chinook salmon. Prog. Fish-Cult., 52: 162-170.Shearer, K. D., and P. Swanson. 2000. The effect of whole body lipid on early sexual maturation of 1+ age male chinook salmon (Oncorhynchus tshawyt-scha). Aquaculture, 190: 343-367.Thorpe, D. K., and J. E. Shanks. 1991. Role of fat stores in the maturation of male Atlantic salmon (Salmo salar) parr. Can. J. Fish. Aquat. Sci., 48: 405-413.Walker, R. V., K. W. Myers, N. D. Davis, K. Y. Ay-din, and K. D. Friedland. 2000. Using tempera-tures from data storage tags in bioenergetic models of high-seas salmon growth. N. Pac. Anadr. Fish. Comm. Bull., 2: 301-308.Watanabe, T. 1982. Lipid nutrition in fish. Comp. Biochem. Physiol. B, 73: 3-75.Wilson, R. P. 1991. Handbook of nutrient require-ment of finfish. CRC Press, London. 196 p.1999年 5月にアラスカ湾で採集されたサケとカラフトマスの筋肉脂質含量野村哲一・K. W. Myers・C. M. Kondzela・J. M. Murphy本間裕美・H. R. Carlson　1999年 5月にアラスカ湾でトロール網で採集されたサケ 99尾とカラフトマス 50尾の筋肉脂質含量について検討した．サケでは海洋年齢 1年および 2年魚の筋肉脂質含量は 3年魚および 4年魚より有意に低い値を示した．カラフトマスでもサケと同様の低い脂質含量であった．海洋年齢 1年および 2年魚の平均脂質含量は，越冬期のサケやカラフトマスの含量とほぼ同様の値であり，越冬期に観察された飢餓状態が若齢魚では春季にも継続していることが示唆された．海洋生活期のサケやカラフトマスの脂質含量を検討する際は年齢の影響を十分考慮する必要がある．さけ・ます資源管理センター研報 Bull. Natl. Salmon Resources Center, No. 4, 200118

Variation in Lipid Content in the Muscle of Chum and Pink Salmon in the Gulf of Alaska in May l999

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Variation in Lipid Content in the Muscle of Chum and Pink Salmon in the Gulf of Alaska in May l999

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