SKJ - iccat

SCRS SKIPJACK Report 2007
40
35
30
25
20
15
10
5
0
-5
-10
-15
-20
-25
-30
-35
-40
-45
-50
-55
-60
-65
-70
-75
-80
-85
-90
-100
-95
70
65
Baitboat
60
55
50
45
40
35
30
25
20
15
10
5
0
Purse seiner
-5
Longline
Bait boat
Purse seine
Other gears
-10
-15
-20
-25
-30
-35
-40
-45
-50
Spatial distribution of the SKJ catches during the period (2000-2004) for
the main fisheries and fishing gears in the Atlantic ocean.
250000
192.000 t
TOTAL
AT.E
200000
AT.W
137.000 t
Catch (mt)
150000
100000
50000
0
1950 1954 1958 1962 1966 1970 1974 1978 1982 1986 1990 1994 1998 2002 2006
year
26.000 t
AT.E
200000
EAST
AT.W
110.000 t
Purse seine
50000
Bait boat
40000
Catch (mt)
Catch (mt)
150000
100000
50000
WEST
Purse seine
Bait boat
30000
20000
10000
0
195019541958196219661970197419781982198619901994199820022006
year
0
1951 1955 1959 1963 1967 1971 1975 1979 1983 1987 1991 1995 1999 2003
year
Eastern Atlantic SKJ
EU purse seiners
FADs
Free
school
Azorean baitboats
SKJ Standardized CPUE Azores BB
9.0
10
YFT
8.0
7.0
tons/fishing day
Scaled CPUE (kg/day-trip)
Dakar based baitboats
6.0
5.0
4.0
3.0
2.0
SKJ
8
BET
All species
6
4
2
1.0
0.0
1970
0
1975
1980
1985
1990
1995
2000
2005
1990
1995
2000
2005
Eastern Atlantic SKJ
and logically regular increase in total
mortality (based on Length data) until
1995 ------ but followed by a dramatic
decline : moratorium effect ? decrease in
fishing effort ?
3.0
Total mortality based on length f requency
2.0
1.5
1.0
Z index
2.5
YFT
BET
SKJ
0.5
Regular decrease in mean weight
(dominated by PS catches) until 1995
1970
1980
1990
2000
Years
Z = K*( L∞ -L moy) / (L moy - L c)
under …. equilibrium conditions
Western Atlantic SKJ
Recent unexplained decline of Venezuelan
PS CPUE, while Brasilian BB CPUEs
remain “stable”
Different patterns observed for mean weight
BB
5,0
PS
SU
4,0
kg
3,0
2,0
1,0
0,0
1969
1974
1979
1984
1989
1994
1999
2004
year
Venezuelan PS index decreases continuously,
while Brazilian BB index drop only in 2004
But … US LL index
increases slowly
Fishery indicators
2005
2003
2001
1999
1997
1995
1993
1991
1989
1987
1985
1983
1981
1979
1977
1975
1973
1971
1969
Eastern Catch
+ + + + + + = = = = = = = = = = = = = = = = = - - - - - - - - - - - - - - -
Z lenght
+ + + + + + + + + + + + + + + + + + + + + + + + + + + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - = = = = = = = = = =
+ + + + + + + + + + + + + + + + + + + + + + + + + = = = = = - - - - - - -
Mean Weight
Skewness Ind.
R. Rate Catch In.
Moratorium
+ + + + + + + + +
1*1 SKJ Catch
+ + + + + + + + + + + + - - - - - + + + + - - - - - = = = = - - - - + + + + + + + + + + + + + + + - - - - - - + + + + + + + + + - - - -
Western Catch
+ + + + + + + + + + + + + + + + + - - - - - - - - - - - - - - - - - - - - -
Car. Capac. EU PS
See you next year for my stock assessment ?
YES, some guys at Corazon de Maria have proposed
to evaluate how many skj we are !, how many time
we move from the meeting room to the cafeteria,
whether the famous FADs in Madrid (i.e., Museo
del Jamon, El abuelo, etc) are still attractive for
ICCAT scientists …., well you know all types of
information very useful for playing with MULTIFAN
CL !.
CAUTION! Attending a SKJ assessment meeting is not dangerous and not cause
irreversible eye damage
It has been evidenced (by a Bayesian Approach) that the SKJ Rapporteur had to wear
glasses BEFORE he started to work with this species.