Pacific Bluefin Tuna Fisheries in Japan and Adjacent Areas before the Mid-20th Century.Muto, F., Takeuchi, Y., & Yokawa, K.National Research Institute of Far Sea Fisheries, FRA, Japan

Ochi, S.Institute for the Study of Japanese Folk Culture, Kanagawa UniversityTabuchi, M.Library and Fisheries Museum, National Research Institute of Fisheries Science, FRA

Figs of gears : Kishinouye 1911, Watanabe 1978.

Prehistoric Tuna Catch, from BC 4,000

Figs of vertebrae : Aita 2007.

Harpoon Head

Harpoon Socket

Hook

Vertebrae, 5cm length

Image of Present Gear

Source：

Yamada & Takeuchi 2007

Recent Catch Statistics for PBF

And Past?

Source: Norin Tokei Kenkyukai 1978

Past statistics including all tuna species.

PBF Catch

PBF = Σ (PBF by Area)

= Σ (PBF Catch Records)

+ Σ (Estimated PBF by Area from TT)

Divide et impera.

+=

Finding PBF Catch Records -1

①

②

③

Industrial Statistics for Oshima Province.Skipjack and Tunas. All About Skipjack and Tunas.History of Japanese Fishing Vessels.History of Japan Tuna Ⅰ. Cooley 1946. Isahaya 1936, 1936. Ishida & Murata 1999. Iehisa 1940. Mine & Iehisa 1940. Nakamura 1939, 1940, 1943, 1951, 1965a, 1965b.Nakayama 1951. Muta 1941. Ota et al. 2005. Taiwan Sotokufu 1944, 1945. Yazaki 1943a-d.

Finding PBF Catch Record - 2

Source: Kawana 1934, 1938, Kawana & Nakajima 1935, Anon. [Kawana & Nakajima ?] 1938

Etorofu, Set Net

*Average size > 100 kg

PBF Catch Records in Hokkaido

Source: Aburatsu Fisheries Association 1972, Gov. Aomori Pref. 1989, Norin Tokei Kenkyukai 1978, Sato 1981.

Catch Records in Honshu & Kyushu

Catch Records in Taiwan

Fishing area of Taiwan-based longliners in 1930’s - 1940’s

•End in June-Smaller fish 150-200 kg

KaohsiungTW

LZStart in April-Large fish > 300 kg

Catch in South Sakhalin by salmon set net.

Source: Isahaya 1936

Supposed migration routes to Sakhalin

Isahaya 1936

redrawn

JP PBF Catch

0

1

2

3

4

5

1946 1947 1948 1949 1950 1951Year

Cat

ch (1

,000

m.t.

) LonglinePole&Line

Catch after the end of World War II.

PBF Catch

PBF = Σ (PBF by Area)

= Σ (PBF Catch Records)

+ Σ (Estimated PBF by Area from TT)

+ =

Motorization

WWIIIn Pacific

Source: Norin Tokei Kenkyukai 1978

Estimate of PBF in Total Tuna catch

• JPPBF1894-1920 = (Coastal Catch of PBF) = T.T. x (Set Net PBF Rate) 1951

• JPPBF1921-1950 = T.T. x (Total PBF Rate) 1951

T.T.: Total Tuna Catch

Areas of almost tuna catches come from PBF.

Hokkaido, Sea of Japan -North, Sea of Japan -West

PBF catch estimation from total tuna catch -1.

Species Method ComponentsA. Hokkaido

Setnet Driftnet Purse Seine

Angling NEI Longline Total

Pacific Bluefin 0.24 0.54 0 0 0.22 1.00

Bigeye 0 0 0 0 0 0.00

Albacore 0 0 0 0 0 0.00

Yellowfin 0 0 0 0 0 0.00

Total 0.24 0.54 0 0 0.22 1.00

Source: Norin Tokei Kenkyukai 1978

•PBF Rate1894-1920 = (Set Net PBF Rate) 1951= 0.24/0.24= 1.00

•PBF Rate1921-1950 = (Total PBF Rate) 1951= 1.00

B. Sea of Japan, northSetnet Driftnet Purse seine Angling NEI Longline Total

Pacific Bluefin 0.92 0 0 0.03 0.007 0.97 Bigeye 0.03 0 0 0 0.007 *0.03Albacore 0 0 0 0 0 0 Yellowfin 0 0 0 0 0 0 Total 0.95 0 0 0.03 0.01 1

Source: Norin Tokei Kenkyukai 1978

•PBF Rate1894-1920 = (Set Net PBF Rate) 1951= 0.92/0.95= 0.97

•PBF Rate1921-1950 = (Total PBF Rate) 1951= 0.97

C. Japan Sea, westSetnet Driftnet Purse seine Angling NEI Longline Total

Pacific Bluefin 0.89 0 0 0.09 0.01 0.99Bigeye 0 0 0 0.01 0 0.01 Albacore 0 0 0 0 0 0Yellowfin 0 0 0 0 0 0 Total 0.89 0 0 0.1 0.01 1.0

Source: Norin Tokei Kenkyukai 1978

•PBF Rate1894-1920 = (Set Net PBF Rate) 1951= 0.89/0.89= 1.00

•PBF Rate1921-1950 = (Total PBF Rate) 1951= 0.99

Areas of Tuna catches come from coastal PBF & offshore other species

Pacific - North

PBF catch estimation from total tuna catch -2.

E. Pacific, northSetnet Driftnet Purse seine Angling NEI Longline Total

Pacific Bluefin Tuna 0.056 0.00 0.26 0.01 0.10 0.42 Bigeye Tuna 0.003 0 0.08 0.05 0.09 0.22 Albacore 0 0 0.00 0.22 0.10 0.32 Yellowfin Tuna 0 0 0.02 0.00 0.01 0.03 Total 0.06 0.00 *0.35 *0.29 0.30 *1.00

Source: Norin Tokei Kenkyukai 1978

•PBF Rate1894-1920 = (Set Net PBF Rate) 1951= 0.056/0.06= 0.95

•PBF Rate1921-1950 = (Total PBF Rate) 1951= 0.42

Seto Inland Sea

East China Sea, Pacific - South, Pacific - Middle

PBF catch estimation from total tuna catch -3.

•PBF Rate1894-1950 = (Total PBF Rate) 1951

Estimated catch of PBF before 1951

Coastal Fisheries

Catch trends before 1920

Estimated catch of PBF before 1951

Drift Net

Catch Trends in 1920’s

Estimated catch of PBF before 1951Coastal FisheriesAburatsu LL

Catch Trends in 1930’s I Case of 1936.

Catch Trends in 1930’s II Case of 1939.

Estimated catch of PBF before 1951

Coastal Fisheries

Drift Net

Coastal FisheriesAburatsu LL

WWII &Decline of Stock

Restart of Fisheries

Comparison of catch trends

Source: Bayliff (1991).

Past JP

Recent JPPast USA

Source: Yamada &Takeuchi 2007

Total tuna catch: Norin Tokei Kenkyukai (1978). Tuna means Thunnus spp.

PBF/All Tuna

Source: Present study + Bayliff 1991, Yamada &Takeuchi 2007, ISC 2007.

World PBF Catch, Tentative Estimation, 1891-2006

Peak: 47,148 m.t. in 1935

Ancient Set Nets in Japan

Habara 1939

Yamaguchi 1932 Tuna set net in Miyagi Pref.From Miyamoto 1952.

Set nets in Toyama Bay area.

“July 7th operation, 3 bluefin tunas, size grade 4, etc.”

Examples: Catch Record from Pacific Side.FY 1805.

From Kumagai-Setsuko Family Record in Library and Fisheries Museum, National Research Institute of Fisheries Science, FRA . Coin indicates 1 cm.

FY 1809.

“April operation, 3 basking sharks, etc.”

Characters of Old Data

• Years for 1848 - 1921 • 6 PBF categories by length.• PBF and other species.

• Years from 1804 • 10 PBF categories by weight.• Mostly PBF with some sharks.

Decoding Them & Searching New.

Conclusions for Japan’s PBF catch before 1951

• No National PBF catch statistics,– local catch information exist.

• Amount roughly estimated,– by piling up catches of areas .– by information of distribution and fishing gear

development.• Amount comparable as present level.• Large fluctuations observed.