SCRS/2009/055
Collect. Vol. Sci. Pap. ICCAT, 65(1): 135-146 (2010)
A SUMMARY ON THE ACTIVITY OF THE SPANISH SURFACE
LONGLINE FLEET CATCHING SWORDFISH (XIPHIAS GLADIUS)
DURING THE YEARS 2006-2007
B. García-Cortés1, J. Mejuto1, J.M. de la Serna2 and A. Ramos-Cartelle1
SUMMARY
This paper presents data on catches, nominal effort and nominal catch rates in 5x5 degree
square formats of the activity of the Spanish surface longline fleet targeting swordfish (Xiphias
gladius) carried out in 2006 and 2007 in waters of the Atlantic (including the Mediterranean
areas), Indian and Pacific Ocean. Graphics and a descriptive summary are also provided. The
nominal catch in round weight of swordfish taken in the ICCAT convention area by Spanish
surface longliners during 2006 and 2007 were 10,746 and 10,847 tons and 1,190 and 1,189
tons in the Atlantic and Mediterranean Sea, respectively. The nominal catch in the Indian
Ocean were 5,155 and 4,796 tons and in the Pacific Ocean 8,259 and 8,430 tons, respectively.
Additionally, data on nominal catch rates for the Atlantic areas are updated for the period
1986-2007.
RÉSUMÉ
Le présent document fournit les données de capture, l’effort nominal et les taux de capture au
format de carrés de 5ºx5º sur l’activité de la flottille palangrière de surface espagnole dirigée
sur l’espadon (Xiphias gladius) au cours des années 2006 et 2007 dans des zones des océans
Atlantique (y compris zones de la Méditerranée), Indien et Pacifique. Des graphiques et des
résumés descriptifs sont également fournis. La capture nominale dans les zones de la
Convention de l’ICCAT réalisée par les palangriers espagnols de surface en 2006 et 2007 s’est
élevée à 10.746 t et 10.847 t dans l’Atlantique et à 1.190 t et 1.189 t en Méditerranée. Les
captures nominales dans l’océan Indien se sont chiffrées à 5.155 et 4.796 t et dans l’océan
Pacifique à 8.259 y 8.430 t, respectivement. En outre, l’information sur les taux de capture
nominale pour les zones de l’Atlantique pendant la période 1986-2007 a été actualisée.
RESUMEN
Se presentan datos de capturas, esfuerzo nominal y tasas de captura en formato de cuadrículas
de 5x5 grados sobre la actividad de la flota española de palangre de superficie dirigida al pez
espada (Xiphias gladius) durante los años 2006 y 2007 en áreas de los océanos Atlántico
(incluyendo áreas del Mediterráneo), Índico y Pacífico. Se facilitan también gráficos y
resúmenes descriptivos. La captura nominal en las áreas del Convenio de ICCAT realizada por
los palangreros españoles de superficie durante 2006 y 2007 fue 10.746 t y 10.847 t en el
Atlántico; y 1.190 y 1.189 t en el Mediterráneo. Las capturas nominales en el Océano Indico
fueron 5.155 y 4.796 t y en el Océano Pacífico, 8.259 y 8.430 t, respectivamente.
Adicionalmente, se actualiza información de tasas de captura nominales para las áreas del
Atlántico durante el periodo 1986-2007.
KEYWORDS
Swordfish, longline, Spanish fleet, CPUE
1
2
Instituto Español de Oceanografía, P.O. Box 130, 15080 A Coruña, Spain.
Instituto Español de Oceanografía, P.O. Box 285, 29640 Fuengirola, Málaga, Spain.
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1. Introduction
Plots and descriptive information of the activity of the Spanish surface longline fleet during the years 2006 and
2007 are included in this paper. Scientific statistical information on the activity of the commercial Spanish
longline fleet is routinely reported to different Regional Fisheries Management Organizations for different
scientific purposes such as the correct interpretation of the indicators to define accurate models for swordfish
stock assessment. This document updates previous papers.
2. Material and methods
The databases from the years 2006 and 2007 include information by 5x5 degree squares on landings, nominal
effort (thousands of hooks), nominal CPUEs in number of fish and weight (kg round weight) per thousand hooks
and size categories, representing the complete activity of this fleet in the Atlantic Ocean and Mediterranean Sea.
Additional information from the Pacific and Indian Oceans was also plotted in this paper to provide a broader
overview. Landings and catches were considered equivalent concepts in this case because the discards are null or
negligible in this fishery.
The nominal CPUE in weight by quarter (Q) is also included (Q1: January, February, March; Q2: April, May,
June; Q3: July, August, September; Q4: October, November, December). The nominal CPUE in number by size
category (CAT) was plotted defining three size groups. Size CAT 1: sizes LJ-FL <= 120 cm., Size CAT 2: sizes
125 cm<= LJ-FL<=160 cm., Size CAT 3: sizes > 160 cm LJ-FL. Additional information on methodological
bases can be found in previous papers (Mejuto et al. 2008).
Taking into consideration that the nominal CPUE is calculated per thousand hooks and that the Spanish fleet has
changed the gear style from the traditional multifilament gear (around 2500 hooks per set) to the monofilament
“American” style longline (around 1500 hooks per set), information on overall nominal catch rates per year
(number of fish and kg round weight, per thousand hooks sets) were also calculated for the North and South
Atlantic stocks for the period 1986-2007.
3. Results
Figures 1 and 2 show plots of landings in number of swordfish and in tons of round weight of the Spanish fleet
during the years 2006 and 2007 including the activity carried out in the Mediterranean Sea, Atlantic, Indian and
Pacific Oceans for general comparative and broader descriptive purposes. Minor activity developed in some
squares of the southeast Atlantic and southwest Indian Oceans where fishing effort was exerted, the catches of
swordfish were null.
During the year 2006 and 2007 a total number of 64 071 and 49 473 swordfishes were size-sampled individually
in the Atlantic Ocean, 44 018 and 5 861 in the Mediterranean Sea, 24 237 and 14 616 a in the Indian Ocean and
in the Pacific Ocean 20 053 and 24 237, respectively. The total surface longline Atlantic swordfish catches were
10 746 and 10 847 tons, 1 190 and 1 189 tons in the Mediterranean Sea, 5 155 and 4 796 tons in the Indian and
in the Pacific 8 259 and 8 430 tons, respectively.
The total fishing effort was 23 071 and 20 761 thousands hooks for the total Atlantic, 12 913 and 6 720
thousands hooks for the Mediterranean, 6 547 and 6 026 thousand hooks for the Indian and 10 141 and 11536
thousands hooks for the Pacific, respectively (Figure 3).
The overall nominal CPUEs in kg of round weight per thousand hooks obtained by the Spanish swordfish fishery
in the years 2006 and 2007 by ocean were 359.1 and 414.3 kg in the North Atlantic, 670.4 and 720.7 in the
South, 92.2 and 177.0 kg for the Mediterranean, 787.5 and 796.0 kg for the Indian Ocean and for the Pacific
814.5 and 730.7 kg, respectively.
Figures 4 and 5 show plots of nominal CPUE in number and CPUE in round weight obtained during 2006 and
2007. A low nominal CPUE obtained in the North Atlantic areas contrasts with the high catch rates occurring in
a large number of squares of the SW Atlantic, Indian and Pacific Oceans, as years before. We must keep in mind
that the preferential gear used by the Spanish surface longline fleet in the SW Atlantic, Indian and Pacific was
the monofilament ‘American’ longline style gear, although this style was also introduced by most of the boats
fishing in the North Atlantic since the year 2000 and the difference in targeting intensity where the North and
136
South Atlantic fleets are now targeting swordfish and blue shark during some sets, trips or in some areas (Mejuto
and de la Serna 2000).
Figure 6 shows nominal CPUE in kg round weight by thousand hooks obtained by quarter during 2006 and 2007
only in the Atlantic and Mediterranean areas. The highest CPUEs seem to be obtained in the North and South
Atlantic areas during Q1 and Q4 as years before, too.
The catch rates (CPUE) in number of fishes per size category for the years 2006 and 2007 are shown in figure 7.
The values obtained by area for the three defined size categories were similar to those obtained years before,
with the highest values in the North Atlantic and Mediterranean Sea for CAT1. High values were also observed
in both the North and South Atlantic for CAT2, with lower values in the Mediterranean areas. The highest values
of CAT3 were observed in South Atlantic areas.
The overall nominal catch rates of swordfish per year, in number and in weight for the period 1986-2007, are
shown in Table 1, Figure 8. The highest catch rates were obtained in the North as in the South Atlantic during
the most recent period after 1999 when the American monofilament longline style was introduced by most of the
fleet, employing much less hooks per set. The catchability per hook is greater in the new style than in the
traditional one. A factor of 2.6 between the catchabilities of both gears was obtained during a survey recently
developed by two vessels using the two different gears in the same areas-times and assuming equal abundanceavailability (Mejuto et al. in press). Using this value as a simple approximation for descriptive purpose, the
recent nominal CPUEs could be converted to the equivalent value of the traditional gear for a simple comparison
with previous periods (Figure 9).
Acknowledgements
We would like to thank E. Majuelos, J. Cebrián, J. Lorenzo and M. Marín, among others, for their untiring
collaboration in compiling the basic information and E. Alot and I. González for updating the databases used in
this paper. This research was carried out with funds from the IEO project SWOATL0710.
References
Mejuto, J., de la Serna, J.M. 2000, Standardized catch rates by age and biomass, for the North Atlantic swordfish
(Xiphias gladius) from the Spanish longline fleet for the period 1983-1998 and bias produced by changes
in the fishing strategy. Collect. Vol. Sci. Pap. ICCAT, 51: 1307-1411.
Mejuto, J., García-Cortés, B., de la Serna, J.M., Ramos-Cartelle, A. ,Activity of the Spanish surface longline fleet
catching swordfish (Xiphias gladius) in the Atlantic Ocean during the year 2005. Collect. Vol. Sci. Pap.
ICCAT, 60(4):1088-1096.
Mejuto, J., Ortiz de Urbina, J., Ramos-Cartelle, A., García-Cortés, B. 2010. In press. Differences in efficiency
between the traditional multifilament and monofilament surface longline styles used by the Spanish fleet
targeting swordfish (Xiphias gladius). ICCAT SCRS/2009/ 098.
137
Table 1. Nominal catch rates per thousand hooks, in number (CPUEn) and in kg round weight (CPUEw), of
swordfish landed by the Spanish surface longline fleet in the Atlantic Ocean (N= North, S= South) for the period
1986-2007.
YR
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
CPUEn_N
6.76
7.10
6.17
6.24
6.13
5.46
5.00
4.81
4.71
4.93
4.62
4.38
5.02
5.02
9.00
10.16
10.63
10.90
9.90
11.18
10.19
11.47
CPUEw_N
334.23
329.51
277.88
258.22
251.57
244.99
227.11
208.52
195.63
201.68
174.07
146.72
170.87
175.44
322.96
360.11
387.20
397.09
365.57
398.76
359.09
414.29
138
CPUEn_S
12.55
10.54
8.52
8.51
8.42
6.94
7.94
10.23
8.76
7.79
7.31
7.09
10.79
10.09
12.31
9.40
11.34
11.61
13.70
14.73
CPUEw_S
654.02
551.19
438.23
437.90
428.31
382.60
419.90
491.66
465.97
402.21
353.90
349.06
501.73
497.18
617.15
450.54
542.65
582.98
670.43
720.72
2006
2007
Figure 1. Number of swordfish landed by the Spanish surface longline fleet in 2006 and 2007 by 5ºx5º squares.
139
2006
2007
Figure 2. Swordfish landings in tons of round weight carried out by the Spanish surface longline fleet in 2006
and 2007 by 5ºx5º squares.
140
2006
2007
Figure 3. Nominal effort in thousands of hooks set by the Spanish surface longline fleet in 2006 and 2007 by
5ºx5º squares.
141
2006
2007
Figure 4. Nominal CPUE in number of swordfish obtained during 2006 and 2007 by the Spanish surface
longline fleet by 5ºx5º squares.
142
2006
2007
Figure 5. Nominal CPUE of swordfish in kg of round weight obtained during 2006 and 2007 by the Spanish
surface longline fleet by 5ºx5º squares.
143
Q1
Q2
Q3
Q4
2006
Q1
2006
Q2
2006
Q3
2006
Q4
2007
2007
2007
2007
Figure 6. Nominal CPUE in kg of round weight of swordfish landed by thousands of hooks set by the Spanish
surface longline fleet by quarter (Q) during 2006 and 2007 in the Atlantic Ocean and Mediterranean Sea.
144
CAT 1-07
CAT 1-06
CAT 2-06
CAT 2-07
CAT 3-06
CAT 3-07
Figure 7. Nominal CPUE in number of swordfish by size class (cm, LJFL): CAT1 < 125 cm; CAT2:125-160
cm; CAT3>160 cm; during 2006 and 2007 in the Atlantic Ocean and Mediterranean Sea.
145
Nominal catch rates
Fish per thosand kooks
16.0
Traditional gear
14.0
American gear
12.0
10.0
8.0
6.0
CPUE#_N
4.0
CPUE#_S
2.0
0.0
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
years
A
Nominal catch rates
800
Traditional gear
Kg per thousand hooks
700
American gear
600
500
400
300
200
CPUEw_N
100
CPUEw_S
0
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
years
B
Figure 8. Nominal catch rates in number (A) and in kg round weight (B) of swordfish landed by thousands of
hooks set by the Spanish surface longline fleet in the Atlantic Ocean (N= North, S= South) for the period 19862007.
Nom inal Catch Rates
Kg per thousand hooks
800
CP UEw_N
CP UEw_S
Transf.CP UEw_N
Transf.CP UEw_S
700
600
500
400
300
200
100
0
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
years
Figure 9. Nominal catch rates in kg round weight of swordfish landed by thousands of hooks set by the Spanish
surface longline fleet in the Atlantic Ocean (N= North, S= South) for the period 1986-2007 (dotted lines show an
approximation of the recent nominal CPUE values using the new longline to the equivalent values of a
traditional style).
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