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Geographical area and description of records.
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Time scale
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Average catches or sightings per year
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Overall (decline) or increase in catches
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Average (decline) or increase per decade
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Achill Island, Ireland. A targeted coastal basking shark fishery
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1947-1975
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360/year in 1947-1950,
1,475/year in 1951-1955,
489/year in 1956-1960,
107/year in 1961-1965,
64/year in 1966-1970,
50/year in 1971-1975.
Rarely seen in 1990s
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(>95% decline in 25 years)
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1940s: increase as fishery develops
(1950s: 65% decline)
(1960s: 30% decline)
(1970s: 20% decline and closure)
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West coast of Scotland
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1946-1953
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121/year throughout fishery.
142/year in 1946-1949,
100/year in 1950-1953.
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(~30% in 7 years, but trend unclear)
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(~30%, but trend unclear)
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Firth of Clyde, Scotland
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1982-1994
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58.6/yr in first 5 years,
4.8/yr in last 5 years.
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(>90% in 12 years)
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(~90%)
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Norwegian catches
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1946-1996
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837/year in 1946-1950
554/year in 1951-1955,
1,541/year in 1956-1960,
1,792/year in 1961-1965,
3,213/year in 1966-1970,
2,236/year in 1971-1975.
1,706/year in 1976-1980
797/year in 1981-1985
343/year in 1986-1990
403/year in 1991-1995
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(87% decline from peak landings in late 1960s to levels in the early 1990s)
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~200% increase, 1950s
~100% increase, 1960s
(1970s: 47% decrease)
(1980s: 80% decrease)
(1990s: 60% overall)
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Northeast Atlantic
(all catches combined)
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1946-1996
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1,254/year in 1946-1950
2,094/year in 1951-1955,
2,030/year in 1956-1960,
1,899/year in 1961-1965,
3,277/year in 1966-1970,
2,385/year in 1971-1975.
1,706/year in 1976-1980
848/year in 1981-1985
355/year in 1986-1990
407/year in 1991-1995
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(90% decline from the main period of peak landings in the late 1960s to landings in the late 1980s)
This followed 20 years of fluctuating but rising catches.
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~40% increase, 1950s
~20% increase, 1960s
(1970s: 40% decrease)
(1980s: 65% decrease)
(1990s: 80% overall)
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Canadian Pacific
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1956-1990s
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50-60/year killed in 1950s
<25/year sighted in 1990s
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(50% decline)
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Data unclear, but a few years of catches resulted in an approximately 50% decline in sightings over 40 years.
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California
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1946-1950s
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300/yr in 1946
200/yr in late 1940s
Fishery closed, early 1950s
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(30% decline in first few years, then fishery closed)
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Data unclear, but a few years of high catches was followed by closure of the fishery.
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Japan
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1967-1990s
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127/yr average, 1967-1974
150 sharks in 1975
20 sharks in 1976
9 sharks in 1977
6 sharks in 1978
Fishery closed, early 1980s
0-2/year sighted in 1990s
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(>95% decline in 10 years)
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Data summarised for first eight years of the fishery, so early trends unclear, but the decline was rapid in the second half of the fishery and has persisted to the present.
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China
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1960-1990
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No quantitative data. Reported to be common in the 1960s, occasionally caught in the 1970s, and rare in 1980s and 1990s.
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(No quantitative data, but decline to very low levels reported.)
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(No quantitative data, but significant decline indicated in the 1960s and 1970s.)
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Isle of Man sightings
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1985-1998
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Table 1 presents steady decrease in sightings/effort.
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(Average sightings declined by ~90%)
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(Average sightings declined by ~90%)
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