139
Fig. 10. Seasonal variations in bluefin tuna abundances and mean lengths in relation to
environmental factors, current speed.
In addition, Figs. 9,11 shows the abundance of Thunnus thynnus as a function of seasonal
variability in sea state (wave height). The wave height in areas of high catch averages 0.9 to
1.33 m in spring and 0.49 to 0.62 m in summer. The coefficient of variation is high, at
0.57 Table 1, Bluefin tuna have the ability to swim in waters with a high variability in energy.
It has been found in calm, low energy waters (about 0 m wave height on average) and even in
very rough, high energy waters due to the effect of wind on the sea surface, with waves of 5.2
m in height. According to (Teo et al., 2007d). Thynnus thynnus in the breeding phase frequents
areas with moderate wind speeds (5-7 m. s-1). Breeding Western Atlantic BFTs favour areas
with moderate eddy kinetic energy, where mesoscale eddies are present (Teo et al., 2007d).
Fig.11.Seasonal variations in bluefin tuna abundances and mean lengths in relation to
environmental factor, wave height.
2.2. Chemical factors
Table 4, shows the link between the chemical and physical factors of the marine environment
and the biotic parameters of the species (size and weight). Fig. 4 and Table 4 show that dissolved
oxygen in seawater is correlated with temperature and salinity with correlation coefficients (r
=-0.64, p<0.0001), and (r = -0.652, p<0.0001) respectively,
Fig. 12. Seasonal variation of the two factor: Temperature and dissolved oxygen.
210,0
220,0
230,0
240,0
250,0
260,0
270,0
11,00
13,00
15,00
17,00
19,00
21,00
23,00
25,00
27,00
2000-Tr2 2000-Tr2_w
2000-Tr3 2001-Tr3 2001-Tr2_w
2001-Tr2 2002-Tr2_w
2002-Tr2 2002-Tr3 2003-Tr2 2003Tr3
2003-Tr2_w
2004-Tr4 2004-Tr2 2004-Tr2_w
2004-Tr3 2005-Tr4 2005-Tr2 2005-Tr3 2005-Tr1 2006-Tr3 2006-Tr2 2006-Tr4 2007-Tr3 2007-Tr2 2007-Tr2_w
2007-Tr1 2007-Tr4
2008-Tr3 2008-Tr2 2009-Tr3 2009-Tr2 2010-Tr3 2011-Tr3 2011-Tr4 2011-Tr2 2012-Tr2 2012-Tr3 2012-Tr4 2012-Tr1 2013-Tr2 2013-Tr4 2013-Tr1 2013-Tr3 2014-Tr3 2014-Tr1 2014-Tr2 2014-Tr4
2015-Tr3 2015-Tr4 2015-Tr1 2015-Tr2 2016-Tr3 2016-Tr1 2016-Tr4 2016-Tr2 2017-Tr3 2017-Tr2 2017-Tr1 2017-Tr4 2018-Tr4
2018-Tr3 2018-Tr2 2018-Tr1 2019-Tr2 2019-Tr1 2019-Tr3
O2
(mmol.m-3)
T
(°c)
Time (trimester)
T (°c)
O2 (mmol.m-3)
-0,3
0,2
0,7
1,2
1,7
2,2
163,8 171,0 155,9
185,5 237,5 171,5
160,0 181,7 179,3 142,6
225,3 296,4 146,9 221,3 187,0 231,7 225,8 205,0
219,8 224,5 255,1 233,8 181,1 226,6 227,5 233,8 221,3 244,4 237,1 215,0 227,5 223,7 220,3 227,1 218,8 237,5 251,3 247,5 227,8 231,2 233,2 226,0 230,7 205,0 223,6 226,0 256,0 229,0 257,5 221,3 226,1 230,8 228,0 258,0 254,6 260,2 230,6 245,0 162,5 169,3 218,7
0
500
1000
1500
2000
2500
3000
3500
2004-Tr2_w 2002-Tr2_w
2007-Tr2 2002-Tr2 2008-Tr2
2003-Tr2_w 2007-Tr2_w
2000-Tr2 2007-Tr3 2004-Tr2 2000-Tr2_w
2006-Tr2 2001-Tr2 2003-Tr2 2005-Tr2 2001-Tr2_w
2006-Tr3 2006-Tr4 2009-Tr2 2013-Tr2 2018-Tr4 2009-Tr3 2016-Tr1 2002-Tr3
2018-Tr1 2018-Tr2 2011-Tr3 2014-Tr3 2014-Tr2 2016-Tr2 2012-Tr2 2004-Tr3 2015-Tr4 2013-Tr3 2018-Tr3 2000-Tr3 2012-Tr1 2017-Tr4 2015-Tr2 2017-Tr2
2017-Tr1 2011-Tr2 2010-Tr3 2013-Tr1 2015-Tr3 2016-Tr3 2013-Tr4 2007-Tr1 2012-Tr3 2015-Tr1 2016-Tr4 2017-Tr3 2005-Tr1 2012-Tr4 2004-Tr4 2014-Tr4 2011-Tr4 2014-Tr1 2001-Tr3 2003Tr3 2005-Tr4 2005-Tr3 2007-Tr4 2008-Tr3 2019-Tr1 2019-Tr3 2019-Tr2
Wave
height
(m)
Lt (cm)
Abundance
Time (trimester)
Headcount (ni)
Wave height (m)
Fig. 10. Seasonal variations in bluefin tuna abundances and mean lengths in relation to
environmental factors, current speed.
In addition, Figs. 9,11 shows the abundance of Thunnus thynnus as a function of seasonal
variability in sea state (wave height). The wave height in areas of high catch averages 0.9 to
1.33 m in spring and 0.49 to 0.62 m in summer. The coefficient of variation is high, at
0.57 Table 1, Bluefin tuna have the ability to swim in waters with a high variability in energy.
It has been found in calm, low energy waters (about 0 m wave height on average) and even in
very rough, high energy waters due to the effect of wind on the sea surface, with waves of 5.2
m in height. According to (Teo et al., 2007d). Thynnus thynnus in the breeding phase frequents
areas with moderate wind speeds (5-7 m. s-1). Breeding Western Atlantic BFTs favour areas
with moderate eddy kinetic energy, where mesoscale eddies are present (Teo et al., 2007d).
Fig.11.Seasonal variations in bluefin tuna abundances and mean lengths in relation to
environmental factor, wave height.
2.2. Chemical factors
Table 4, shows the link between the chemical and physical factors of the marine environment
and the biotic parameters of the species (size and weight). Fig. 4 and Table 4 show that dissolved
oxygen in seawater is correlated with temperature and salinity with correlation coefficients (r
=-0.64, p<0.0001), and (r = -0.652, p<0.0001) respectively,
Fig. 12. Seasonal variation of the two factor: Temperature and dissolved oxygen.
210,0
220,0
230,0
240,0
250,0
260,0
270,0
11,00
13,00
15,00
17,00
19,00
21,00
23,00
25,00
27,00
2000-Tr2 2000-Tr2_w
2000-Tr3 2001-Tr3 2001-Tr2_w
2001-Tr2 2002-Tr2_w
2002-Tr2 2002-Tr3 2003-Tr2 2003Tr3
2003-Tr2_w
2004-Tr4 2004-Tr2 2004-Tr2_w
2004-Tr3 2005-Tr4 2005-Tr2 2005-Tr3 2005-Tr1 2006-Tr3 2006-Tr2 2006-Tr4 2007-Tr3 2007-Tr2 2007-Tr2_w
2007-Tr1 2007-Tr4
2008-Tr3 2008-Tr2 2009-Tr3 2009-Tr2 2010-Tr3 2011-Tr3 2011-Tr4 2011-Tr2 2012-Tr2 2012-Tr3 2012-Tr4 2012-Tr1 2013-Tr2 2013-Tr4 2013-Tr1 2013-Tr3 2014-Tr3 2014-Tr1 2014-Tr2 2014-Tr4
2015-Tr3 2015-Tr4 2015-Tr1 2015-Tr2 2016-Tr3 2016-Tr1 2016-Tr4 2016-Tr2 2017-Tr3 2017-Tr2 2017-Tr1 2017-Tr4 2018-Tr4
2018-Tr3 2018-Tr2 2018-Tr1 2019-Tr2 2019-Tr1 2019-Tr3
O2
(mmol.m-3)
T
(°c)
Time (trimester)
T (°c)
O2 (mmol.m-3)
-0,3
0,2
0,7
1,2
1,7
2,2
163,8 171,0 155,9
185,5 237,5 171,5
160,0 181,7 179,3 142,6
225,3 296,4 146,9 221,3 187,0 231,7 225,8 205,0
219,8 224,5 255,1 233,8 181,1 226,6 227,5 233,8 221,3 244,4 237,1 215,0 227,5 223,7 220,3 227,1 218,8 237,5 251,3 247,5 227,8 231,2 233,2 226,0 230,7 205,0 223,6 226,0 256,0 229,0 257,5 221,3 226,1 230,8 228,0 258,0 254,6 260,2 230,6 245,0 162,5 169,3 218,7
0
500
1000
1500
2000
2500
3000
3500
2004-Tr2_w 2002-Tr2_w
2007-Tr2 2002-Tr2 2008-Tr2
2003-Tr2_w 2007-Tr2_w
2000-Tr2 2007-Tr3 2004-Tr2 2000-Tr2_w
2006-Tr2 2001-Tr2 2003-Tr2 2005-Tr2 2001-Tr2_w
2006-Tr3 2006-Tr4 2009-Tr2 2013-Tr2 2018-Tr4 2009-Tr3 2016-Tr1 2002-Tr3
2018-Tr1 2018-Tr2 2011-Tr3 2014-Tr3 2014-Tr2 2016-Tr2 2012-Tr2 2004-Tr3 2015-Tr4 2013-Tr3 2018-Tr3 2000-Tr3 2012-Tr1 2017-Tr4 2015-Tr2 2017-Tr2
2017-Tr1 2011-Tr2 2010-Tr3 2013-Tr1 2015-Tr3 2016-Tr3 2013-Tr4 2007-Tr1 2012-Tr3 2015-Tr1 2016-Tr4 2017-Tr3 2005-Tr1 2012-Tr4 2004-Tr4 2014-Tr4 2011-Tr4 2014-Tr1 2001-Tr3 2003Tr3 2005-Tr4 2005-Tr3 2007-Tr4 2008-Tr3 2019-Tr1 2019-Tr3 2019-Tr2
Wave
height
(m)
Lt (cm)
Abundance
Time (trimester)
Headcount (ni)
Wave height (m)