海上網生簀における天然プランクトンを用いたマダラの半粗放的種苗生産

Size: px

Start display at page:

Download "海上網生簀における天然プランクトンを用いたマダラの半粗放的種苗生産"

ありさうづき
5 years ago
Views:

1 Aquacult. Sci , Semi-extensive larviculture of pacific cod Gadus macrocephalus utilizing wild zooplankton in the sea net-cage Tsutomu TOMODA 1, Kazunori KUMON 2, Ken-ichi WATANABE 3, Daisuke ARAI 4, Masahiko KOISO 5, Nobuhiro TEZUKA 6, Kazuo HOTTA 7 and Hiroshi KUWADA 8 Abstract: The present study intends to develop larviculture techniques for mass production of Pacific cod Gadus macrocephalus juveniles possessing better seed quality and lower cost. We evaluated the efficiency of semi-extensive larviculture of Pacific cod utilizing wild zooplankton in the sea net-cage. Main food was light-allured zooplankton and supplementary foods were enriched Artemia nauplii, commercial frozen copepoda and dry feed. Metamorphosing cod larvae (12 and 13 mm in total length, TL) were raised until approximately 30 mm TL, and larvae and metamorphosed juveniles (17, 19, and 20 mm TL) were raised until 45 to 50 mm TL. Survival rates ranged from 46.4 to 48.7 in the former groups, and from 51.4 to 76.5 in the latter groups. A total of and thousand juveniles were produced in each semi-extensive trial. Moreover, semi-extensive method offered the benefits of labor saving and cost reduction. One juvenile with 30 mm and 45 to 50 mm TL cost only 6.4 yen and 6.2 to 10.5 yen, respectively. These results suggest that cod larviculture utilizing wild zooplankton in the sea net-cage provides faster growth, higher survival rate, and lower cost. We propose that this rearing method may be applicable to various fish species for stock enhancement. Key words: Pacific cod; Sea net-cage; Semi-extensive larviculture; Zooplankton National Research Institute of Aquaculture, Fisheries Research Agency, Shibushi Laboratory, Natsui, Shibushi, Kagoshima , Japan 2 Seikai National Fisheries Research Institute, Fisheries Research Agency, Amami Laboratory, Setouchi, Oshima, Kagoshima , Japan 3 Department of Aquatic Bioscience, Faculty of Bio-industry, Tokyo University of Agriculture, Abashiri, Hokkaido , Japan 4 Research Promotion Division, Agriculture, Forestry and Fisheries Research Council, Kasumigaseki, Chiyoda-ku, Tokyo , Japan 5 Seikai National Fisheries Research Institute, Fisheries Research Agency, Yaeyama Laboratory, Fukai-Ohta, Ishigaki, Okinawa , Japan 6 Japan Sea National Fisheries Research Institute, Fisheries Research Agency, Miyazu Laboratory, Odashukuno, Miyazu, Kyoto , Japan 7 Fisheries Research Institute, Toyama Prefectural Agricultural, Forestry & Fisheries Research Center, Takatsuka, Namerikawa, Toyama , Japan 8 National Research Institute of Aquaculture, Fisheries Research Agency, Minami-izu Laboratory, Irouzaki, Kamo, Shizuoka , Japan Corresponding author : Tel, (+81) ; Fax, (+81) ; , ttomoda@fra.affrc.go.jp T. Tomoda

2 Gadus macrocephalus ; ; ; ; 1995, 1996, 1997; 2003; Matsunari et al ; , 2001; , 2009; Tomoda et al ; Shields 2001 Arctoscopus japonicus 2002; G. morhua Brown et al. 2003; Rosenlund and Halldórsson l MPC kl 45 kl 20 l Fig. 1 ESF-030 M2 15 1PL 110V-60 W Brachionus plicatilis sp. complex L m Artemia sp mm50 70 A-400, B-400, 700 C-700, 1000 ; 200, 400, ; 2003; 2003; 2005; Matsunari et al. 2005

3 / 50 kl mm m20 kl 1 2,345 3,640 /kl mm ,326 4,661 /kl 1 2, /kl mm T mm A 50.6 mm Z-65L 500 l SPS-500 FCH-10 2 l 3 6 l 1 l l 10 l l 10 l 5 5 N Fig. 1 1 Fig mm ,500 / A1 250 ml/ Cyclopeeze Argent Chemical Laboratories; g/ B-400, 700, N-400, 700, C-700, 1000 ; 200, 400, 600, 800; No. 5, mm YDF-160SO A / 2 12 / g/ kg 8 3kg 2 kg m 3 cm 2002; M 1 C M 2 C M 3 C Mt C t M 1 M 2 M 3 Mt t C = D/D' D D' N 0 Nt t S = Nt/N 0

Fig. 2. Semi-extensive larviculture of Pacific cod Gadus macrocephalus in sea net-cages with plankton-alluring lamps.

4 Fig. 1. Current larviculture protocols for juvenile Pacific cod Gadus macrocephalus in Notojima Laboratory, JSNFRI, FRA. Dotted lines indicate supplementary utilization of each food. A red bold line indicates a main food in semi-extensive method. Fig. 2. Semi-extensive larviculture of Pacific cod Gadus macrocephalus in sea net-cages with plankton-alluring lamps. a, Daytime; b, Nighttime. D = 1-S D' = (M 1 +M 2 +M 3 + +Mt)/N 0 M 1 M 2 M 3 Mt C N DF l/ XX80 m 2002;

5 1 2006; ,000 / 2,800 / 750 / Table mm mm Fig mm mm mm mm 1, mm 13 mm 4 Fig mm mm mm mm mm mm 1, mm 4 17 mm Table 1. Results of semi-extensive larviculture trials of Pacific cod Gadus macrocephalus in the sea net-cages Year Group Number of fish ( 10 3 ) Initial Rearing Final Stocking density (ind./kl) Total length 1 (mm) Number of cage 2 (N) mm Semi-extensive , Temperature 3 (ºC) 10.5 ( ) Period (days) Number of fish ( 10 3 ) Stocking density (ind./kl) Total length 1 (mm) Survival rate ( ) , mm Semi-extensive , mm Extensive (Control) mm Semi-extensive , mm Extensive (Control) mm Semi-extensive , mm Semi-extensive , mm Semi-extensive , Mean S.D. (n = ) 2 Net-cage ; Scale m (volume 20 kl) 3 Mean (Min Max) 10.5 ( ) 10.3 ( ) 10.3 ( ) 10.1 ( ) 9.7 ( ) 10.5 ( ) 10.6 ( ) , , , , ,

6 Fig. 3. Survival curves of Pacific cod Gadus macrocephalus larvae and juveniles during larviculture trials in sea netcages. +, 12mm Semi-extensive A;, 12mm Semi-extensive B; +, 12mm Semi-extensive C;, 12mm Semi-extensive D;, 13mm Extensive;, 13mm Semi-extensive A;, 13mm Semi-extensive B;, 13mm Semi-extensive C;, 17mm Extensive;, 17mm Semi-extensive A;, 17mm Semi-extensive B;, 17mm Semi-extensive C;, 19mm Semi-extensive 1;, 19mm Semi-extensive 2;, 20mm Semi-extensive 1;, 20mm Semi-extensive 2. Fig. 4. Daily changes of number of food organisms collected from the sea net-cage. +, 2000 (Morioka 2002);, 2002;, 2003 (this study);, 2004 (this study);, 2005 (Arai et al. 2006);, 2006 (Arai et al. 2009).

7 Fig mm 17 mm 17 mm Fig / / Cladocera Copepoda ; 2006, 2009 Table 2 Table , ,655 Table mm 30 mm 6.4 / / 17 mm 50 mm 10.5 /19 20 mm mm / 19 mm 30 mm / Table 2. Total amount of food, rearing gear and total hours spent at work required in semi-expensive larviculture of Pacific cod Gadus macrocephalus in the sea net-cage Year 1 Group Artemia nauplii ( 10 8 ind.) Commercial frozen copepoda (kg) Commercial dry feed (kg) Major rearing gear (piece) Net-cage Sinker Automatic feeder Feed controller Total hours spent at work (man hour) Staff Part-timer mm Semi-extensive mm Semi-extensive mm Semi-extensive mm Semi-extensive mm Semi-extensive mm Semi-extensive Cod larvae were raised until approximately 30 mm TL in 2003, and larvae and juveniles were raised until 45 to 50 mm TL except for 19 mm Semi-extensive 1 in Table 3. Estimate of expenses in semi-expensive larviculture of Pacific cod Gadus macrocephalus in the sea net-cage Year 1 Group Feed cost ( 10 3 yen) Depreciation expense ( 10 3 yen) Utillty expenses ( 10 3 yen) Personnel expenses ( 10 3 yen) Total cost ( 10 3 yen) Unit cost 2 (yen/fish) mm Semi-extensive mm Semi-extensive mm Semi-extensive mm Semi-extensive mm Semi-extensive mm Semi-extensive Cod larvae were raised until approximately 30 mm TL in 2003, and larvae and juveniles were raised until 45 to 50 mm TL except for 19mm Semi-extensive 1 in (Total cost) / (Number of produced fish)

8 Table , 2009; Tomoda et al ; 2008 Takatsu et al. 1995; 2002; Fig mm mm mm 18 mm 15 mm 18 mm 20 mm m 17 mm 20 mm mm 19 mm mm mm 30 mm mm mm 30 mm Table ; 2006, / Takatsu et al. 1995; 2002;

9 mm / 2008 Fig. 1 Table 2 97Table mm 12.7 / Fig mm 3.6 / mm 30 mm / Table / 19 mm 30 mm 19 mm 1 45 mm 19 mm 2 30 mm Table , 2009; Tomoda et al ; ; ; Shields 2001; mm 30 mm mm mm

10 30 mm mm Gadus macrocephalus [Arai, D., T. Tomoda and T. Morioka (2006) Larval culture of Pacific cod using net cages in the sea with zooplankton. Aquacult. Sci., 54, (in Japanese with English [Arai, D., T. Tomoda, N. Tezuka and K. Hotta (2009) Starvation resistance of Pacific cod (Gadus macrocephalus) larvae and juveniles reared in the sea netcage. Aquacult. Sci., 57, (in Japanese with English Brown, J. A., G. Minkoff and V. Puvanendran (2003) Larviculture of Atlantic cod (Gadus morhua): progress, protocols and problems. Aquaculture, 227, [Fujita, D. and K. Hotta (1998) On the recent catch of Pacific cod Gadus macrocephalus in Toyama prefecture. Bull. Toyama Pref. Fish. Res. Inst., 10, (in Japanese with English [Iwamoto, A., H. Yamazaki, H. Fujimoto, S. Okumura, Y. Yamamoto and Y. Obata (2006) Estimation of seed production costs for the Japanese Spanish mackerel, Scomberomorus niphonius. Saibai Giken, 33, (in Japanese with English pp. [Ed. by Kitajima, C. (1993) Healthy Fry for Release, Kouseishakouseikaku, Tokyo, 119 pp (in Japanese).] Matsunari, H., D. Arai, M. Koiso, H. Kuwada, T. Takahashi and T. Takeuchi (2005) Effect of feeding rotifers enriched with taurine on growth performance and body composition of Pacific cod larvae Gadus macrocephalus. Aquacult. Sci., 53, [Morioka, T. and H. Kuwada (2002) The upper limit of inhabiting temperature and the diet of juvenile Pacific cod Gadus macrocephalus in the northern part of Nanao Bay and its vicinity, Japan. Nippon Suisan Gakkaishi, 68, (in Japanese with English [Morioka, T. (2002) The diet of japanese sandfish Arctoscopus japonicus larvae and juveniles reared in a net-cage with a plankton-alluring lamp. Nippon Suisan Gakkaishi, 68, (in Japanese with English pp No pp pp. [Ohno, A. (1992) Fundamental study on the extensive seed production of the red seabream, Pagrus major. Special Research Report No. 2, Japan Sea-Farming Association, Tokyo, 110 pp (in Japanese with English Rosenlund, G. and O. Halldórsson (2007) Cod juvenile production: Research and commercial developments. Aquaculture, 268, Shields, R. J (2001) Larviculture of marine finfish in Europe. Aquaculture, 200, Takatsu, T., T. Nakatani, T. Mutoh and T. Takahashi (1995) Feeding habits of pacific cod larvae and juveniles in Mutsu Bay, Japan. Fish. Sci., 61, [Takatsu, T. (2003)

11 Field research on spatial and temporal distributions of demersal fish larvae and juveniles and their prey abundance. Nippon Suisan Gakkaishi, 69, (in Japanese).] 1994 DHA [Takeuchi, T., F. Zheng, K. Yoseda, J. Hirokawa and T. Watanabe (1994) Nutritive value of DHA-enriched rotifer for larval cod. Nippon Suisan Gakkaishi, 60, (in Japanese with English [Tezuka, N. (2006) Session 6: Broodstock rearing of resource fishes. A concrete example for rearing broodstock of Pacific cod (Gadus macrocephalus). In Reproductive properties and environmental effects on reproduction in resource fishes. Bull. Fish. Res. Agen. Supplement No.4, (in Japanese with English [Tomoda, T. and S. Dan (2014) Stagnant water larviculture using the rotifer Brachionus plicatilis acclimated at low temperature in Pacific cod Gadus macrocephalus. Aquacult. Sci., 62, (in Japanese with English Tomoda, T., D. Arai, N. Tezuka and K. Hotta (2009) Towards the improvement in seed quality of reared Pacific cod (Gadus macrocephalus). In Larvi 09 Fish & Shellfish Larviculture Symposium (ed. by C. I. Hendry, G. Van Stappen, M. Wille and P. Sorgeloos), European Aquaculture Society Special Publication no. 38, pp (2) [Zheng, F., T. Takeuchi, K. Yoseda, J. Hirokawa and T. Watanabe (1995) Changes in fatty acid composition of cod larvae in mass production. Nippon Suisan Gakkaishi, 61, (in Japanese with English 1996 EPA DHA [Zheng, F., T. Takeuchi, K. Yoseda, M. Kobayashi, J. Hirokawa and T. Watanabe (1996) Requirement of larval cod for arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid using by their enriched Artemia nauplii. Nippon Suisan Gakkaishi, 62, (in Japanese with English 1997 E DHA [Zheng, F., T. Takeuchi, M. Kobayashi, J. Hirokawa and T. Watanabe (1997) A study of vitamin E absorption in rotifer and cod larvae and the effect of DHA content in rotifer for cod larvae. Nippon Suisan Gakkaishi, 63, (in Japanese with English

Table 1. Number and stundard length of smallmouth bass examined in the study

Table 1. Number and stundard length of smallmouth bass examined in the study Taiga Yodo* and Kei'ichiro Iguchi. 2003. Feeding habits of introduced smallmouth bass in Lakes Aoki and Nojiri, Japan. Japan. J. Ichthyol., 50(1): 47-54. Abstract To elucidate the feeding habits of smallmouth