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5 Sea of Japan Hokkaido Okhotsk Sea Study area Number of fish released (thousand) 120, ,000 80,000 60,000 40,000 20, Year Fish released in rivers Fish released from net-pens

6 Number of fish released (thousand) 12,000 10,000 8,000 6,000 4,000 2, May June Date Return rate (%) Year Mean weight (g) Return rate (%) Mean weight at release (g)

7 Return 8-days period (counted consecutively by defining 1-8 January as the first) Year of rate 17th 18th 19th 20th 21st 22nd 23rd 24th 25th release (%) 9-16 May May 25 May-1 Jun 2-9 Jun Jun Jun 26 Jun-3 Jul 4-11 Jul Jul No Data No Data No Data No Data No Data No Data No Data No Data No Data Period of SST within 8-13 No Data

8 20 20 Return rate (%) y = -3.15x R 2 = 0.60 P < First period reaching 8 Return rate (%) y = -2.08x R 2 = 0.41 P < First period exceeding 13

9 20 17th 8-days period (9-16 May) 20 18th 8-days period (17-24 May) 19th 8-days period (25 May-1 June) 20 Return rate (%) y = x R 2 = P > SST Return rate (%) y = 0.49x R 2 = P > SST Return rate (%) y = 3.10x R 2 = 0.58 P < SST Return rate (%) th 8-days period (2-9 June) y = 0.11x R 2 = P > 0.05 Return rate (%) st 8-days period (10-17 June) y = 0.31x R 2 = P > SST SST

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15 Upper marking reach Falls Sea of Japan Hokkaido Pacific Ocean Hidarimata River Lower marking reach Sea of Japan Atsuta River

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17 1998 Number of fish Late July Lower reach Male Female Upper reach Number of fish Mid-August Male Female Lower reach Upper reach 1999 Number of fish Late July Male Female Lower reach Upper reach Number of fish Mid-August Male Female Lower reach Upper reach Number of fish Late August Male Female Lower reach Upper reach

18 Number of fish Male Female 9/8-9 9/18 9/24 10/2 Number of fish Male Female /2 9/7 9/15 9/ / /6

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23 St.1 (6000m) Oyobe River St.2 (4500m) St.3 (3000m) 44 N 42 N St.4 (1200m) St.5 (300m) 140 E Sea of Japan 145 E Sea of Okhotsk Hokkaido Pacific Ocean Tsugaru Strait

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25 Frequency Frequency Frequency Fork length ( cm ) Body weight ( g ) Condition factor Oct 30-Nov 29-Jan 29-Mar Month Seasonal changes in the average fork le 1-Oct 30-Nov 29-Jan 29-Mar Month 1-Oct 30-Nov 29-Jan 29-Mar Month

26 Fork length ( cm ) Body weight ( g ) Condition factor Distance of mouth ( km ) Distance of mouth ( km ) Distance of mouth ( km ) Stomach contents index 1.2 St.1St A B,C B,D A,C,D D J F M Month Water temperature ()

27 Stomach contents index Dec.Mar. a,b St.1 St.2 St.3 St.4 St.5 a Sampling site b

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35 Sea of Japan Date Fishing Port Kesen Dai-ichi Hatchery C.Chikyu Sea of Okhotsk Hokkaido Osaru R. Pacific Ocean Shiraoi Fishing Port 250Km Tomakomai Fishing Port

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37 Mean body weight (g) /1 11/21 12/11 12/31 1/20 2/9 3/1 3/21 4/10 4/30 5/ Number of individuals May 22 Feb Feb May March May Body weight(g)

38 Number of fish Sea of Okhotsk Number of fish Sea of Okhotsk Sea of Japan Sea of Japan Pacific Ocean Pacific Ocean N=505 N=192

39 Number of fish Sea of Okhotsk Number of fish Sea of Okhotsk Sea of Japan Sea of Japan Pacific Ocean Pacific Ocean N=10 N=179 Number of fish Sea of Japan Sea of Okhotsk Mean body weight(g) 3,000 2,500 2,000 1,500 1, J J A S O N D J F M A M J Release year Next year Pacific Ocean N=62

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47 Individual numbers m 2 Individual numbersm 2

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49 R R Jul Oct R R Feb Apr R R Mar May R R Jul Oct 2002

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51 e1 e2 e3 e Velocity at the Distance from Unfixed cobbles Water depth stream bed stream edge e9 Physical environment e Total individual numbers 0.32 Benthic macroinvertebrates Number of taxa Total wet weight 0.46 e7 e6 e5

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