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.