An introduction of Stock Enhancement in Kanagawa, Japan Provincial Court, Bruges, Belgium 7-8 May,2007 Toshitame IMAI Kanagawa Prefectural Fisheries Technology.

An introduction of Stock Enhancement in Kanagawa, Japan

Provincial Court, Bruges , Belgium 7-8 May ,2007

Toshitame IMAI

Kanagawa Prefectural Fisheries Technology CenterYoroshi, Jogashima, Misaki, Miura

Kanagawa 238-0237, JapanEmail: [email protected]

A location of Kanagawa

Catch

Pleasure16%

Fishery84%

Total landing of fisheries

0% 20% 40% 60% 80% 100%

Sillagonoid

Squid

Amberjack

Frigate mackerl

Sweetlip

Fish glue

Scomber

Flat fish

PleasureFishery

Ratio of each fish species in total landing

Landings of commercial 　 and sports fishing in Kanagawa

Brief 　 History 　 of Stock Enhancement Activities in Kanagawa Prefecture

1966 Establishment of R/D facility of hatchery technology1967 R/D of live feed culture & larviculture1974 ～ Fundamental studies on fishery biology of the red sea bream,

the Japanese flounder, and abalone 1975 Development of the technologies on mass production of live

feed and a mechanical bottom cleaner1976 The 1st hatchery for stock enhancement1975- R/D of large scale larviculture technologies 1977 （ Rotifer fortification examination, water tank bottom vacuum cleaner device development)1978 ～ Large scale restocking activity of red sea bream using 1million

hatchery-raised juveniles, tagged 10% juveniles1986 Tag and recapture experiment on hatchery-raised red sea

bream juveniles

1984 Enforcement of the 1st basic plan for stock enhancement （ The 　 5th plan, 2006) 1987 A pilot proof examination (recovery ratio, cost- effectiveness, benefit principle ratio)1989 An association of Kanagawa Fish Farming Foundation established1990 Investigation of measures on the management of stock enhancement of marine resources ( setting an closed fishing area, season, releasing a small fish)1990 Construction of the 2nd hatchery for stock enhancement

2000 Introducing a benefit 　 principle system

Brief 　 History 　 of Stock Enhancement Activities in Kanagawa Prefecture, contn’d

A promotion system of sea farming

Board of director

Secretariat

Management sec.

Operation sec.

CaputInspector

Support

City Town

Assoc.

Kanagawa

Fish

farming

Found.

Kanagawa

Pref.

Fish.

Tec.

Center

Coop.

Play fishing

Boat

supplier

Fishermen

Angler Support

Member.

Organization of Fish farming found

An aerial photograph of Kanagawa Prefectural Fisheries Technology Center

Cultivation Tank of Rotifer and Green Water

Rearing Tank and Drain Cage, Bottom Cleaner

Development of Red Sea bream

Releasing Hatchery Raised Red Sea Bream

A Sports Fishing Boat of Red Sea Bream in Tokyo Bay

Landing sight on Fish market

Measurement of red sea bream

Target species of stock enhancement in Kanagawa Prefecture

2002 2001J apanese nameEnglish name Scientific name Produced Released

(ton) × 1000クロアワビ Disk abalone Haliotis discus discus 2 144マダカアワビ Giant abalone H.madaka 5 149メガイアワビ Giant abalone H.gigantia 10 202トコブシ J apanese abalone H. diversicolor 5.9 0サザエ Spiny top shell Batillus cornatus 173 739マダイ Red sea bream Pagurus major 33 1006ヒラメ J apanese flounder Paralichthys olivaceus 56 535ホシガレイ Spotted halibut Veasper variegatus 0 15マコガレイ Mud dab Limanda yokohmae 46 229

クルマエビ Kuruma prawn Penaeus japonicus 1.8 90ガザミ Swimming crab Portunus trituberculatus 4.4 5カサゴ Scorpion fish Sebasticus mormoratus - 62

Red: Association production 　　　 Yellow: purchase from outside

Black: Technology Center production

Blue: Discontinue

Annual changes of stocking number

0

200000

400000

600000

800000

1000000

1200000

1400000

Red sea breamBl ack sea breamFl ounderAbal oneTop shel lSwi mmi ng crabKuruma Prown

Recapture rate of stock enhancement

J apanese nameEnglish name Scientific name Recovery rate(%)

クロアワビ Disk abalone Haliotis discus 3 7～マダカアワビ Giant abalone H.madaka 5 12～メガイアワビ Giant abalone H.gigantia 6 10～トコブシ J apanese abalone H. diversicolor 15 20～サザエ Spiny top shell Batillus cornatus 30 35～マダイ Red sea bream Pagurus major 4 12～ヒラメ J apanese flounder Paralichthys olivaceus 3 10～ホシガレイ Spotted halibut Veasper variegatus -

Cost-effectiveness

: mi l l i on yenEngl i sh name Expense Catch Pl ay fi shi ng Cost-

amount money amount money eff ecti venessA B C B+C/ A

Red Sea Bream 32 19 64 2. 6Fl atfi sh 12 34 2. 8Abal one 25 147 5. 9Top shel l 14 46 3. 3 But we remove personal expenses, the i nsti tuti on repayment coast

種苗放流数と捕獲量

0

20

40

60

80

100

120

140

0

20

40

60

80

100

120

140

Sport(ton) Commercial(ton) Released seed

‘‘57 ‘66 ’78 ‘00

The catch by commercial and sports fishermen and the number of released juveniles of red sea

bream in Kanagawa Prefecture.

A ratio of hatchery-raised fish and wild fish in landing

10平成 年度天然魚・放流魚比率

放流魚(47 )千尾

37%

天然魚(79 )千尾

63%

捕獲尾数126千尾

Hatchery

wild

Thousand indi.

Development of a tagging method for a fry

• We attached an anchor tag to red sea bream fry with length 6-8cm since 1978 to 1989 and released 1,000,000 of them in total.

• The recapture rate was 1%.

• Movement, growth became clear by anchor tag planting of fish.

• However, a calculation of a recovery was not possible by falling off of a tag, and lacking of a recapture report.

Development of a marking method for a fry

• Furthermore, we developed a new technology using ALC as a mark to a fry, and to dye a scale. A method to make a mark in alizalin complexone stained an otolith conventionally

Optical　microscope

Fluorescent microscope

The deformity of inter-nostril epidermis as a mark of hatchery-raised fish

A contribution breakdown of an endowment

Kanagawa Pref ecture

Associ at i on of fi shermen' scooperat i ve associ at i onsoci et y

A fi shermen' s cooperat i veassoci at i on

Ci t y

A fi shery group

An associ at i on

A sum of an endowment

761,170 thousand yen

A change of an income breakdown of Association of Kanagawa fish farming Foundation

0

50000

100000

150000

200000

250000A f ee

A busi ness

Money ofcooperat i on

Money of burden

A subsi de

Endowment use

An i ncome

Thousand yen

The ratio of seeds production capital before and after inducing cooperate money from the red sea

bream fishing angler

1573000

9853000

20674000

Before After

12384634000000

80000004272000

4772605

7007075

Endowment

Subsi de

Fi shermen

Party boat

Angl er

Profi tbusi ness

20674000

After

Total \29,290,143Total \32,100,000

19992005

Development of Zostera bed

• Shallow waters of Tokyo Bay had very large eelgrass ground until 1960’s.

• However, reclaim advanced for high economic growth after 1960’s, and shallow waters level lost it.

• As a result, the seat which larvae of fishery products brought up disappeared, and quantity of fishery decreased sharply.

• Therefore we perform a trial to restore eelgrass ground

The genetic selection of stocks used for restocking purposes

• In addition ,we pay it around 20% for the parent in every year and perform a substitute

• We coast the number of parent fish more than 500 of them to keep genetic variety

• We monitor mt-DNA and microsatellite DNA about a gene of a released fish and a fishery fish now.

Hap

rotyp

e com

po

sition

•Thank you very much for your kind attention