Only age group 0 hake is linked with this environmental scenario. Hake
recmitment processes in the area lead to well-defined patches of juveniles, which were found in localised areas of the continental shelf. In the
Cantabrian Sea, these concentrations vary in density according to the
strength of the year class, although they remain relatively stable in size
and spatial location (Sánchex & Gil, 2000). The size and location of the
patches found during the SliSlTS sun eys (SI .SITS, 2000) show rhat the bav
of Biscay appears to be the main nursery area for European hake. In
1997, the level of recruitment obtained in the French bav of Biscay,
Cantabrian Sea and Galician waters was higher than în 1998, the contrary
being observed m the Celtic Sea. Areas of high concentration of hake
recruits were located at depths between 80 to 200 m and over predominantly muddy bottoms. However, the aggregation patterns were different
on both sides of the bay of Biscay and in the Celtic Sea. The Spanish
patches (Cantabrian Sea and Galicia) were smaller and denser than the
French ones and the low recruitment during 1998 was located in the
same areas but with low density.
In the Cantabrian Sea, the hydrographic results show that the situation of
the hake recruifs coincides with the presence of mesoscale anticyclonic
strucmres. This situation may be explained by ichtyoplankton retention
within the gyres, and subsequent transport of larvae and pre-recruits from
the spawning areas towards these nurseries. The differences between
1997 and 1998 appeared conceming upwelling strength and mesoscale
activity’ (fig. 3). In 1997, the dynamic pattem was formed by a threestripped pattem of: (a) cold upwelling cyclonic nuclei along the continental shelf; (b) warm mesoscale off-shelf anricyclones; and (c) colder and homogeneous off-slope oceanic waters. In 1998, it was configured bv: (a)
well-stratified, warm and low salinim waters; and (b) colder and homogeneous oceanic waters; both (a) and (b) with minor mesoscale features.
Therefore, we suppose that the intense mesoscale acrivity and upwellingin
1997 were the cause of the good recruitment found in the Cantabrian Sea.
On the contrary, the absence of this hydrographic phenomenon could be
the reason for the failure of the 1998 recruitment.
176
recmitment processes in the area lead to well-defined patches of juveniles, which were found in localised areas of the continental shelf. In the
Cantabrian Sea, these concentrations vary in density according to the
strength of the year class, although they remain relatively stable in size
and spatial location (Sánchex & Gil, 2000). The size and location of the
patches found during the SliSlTS sun eys (SI .SITS, 2000) show rhat the bav
of Biscay appears to be the main nursery area for European hake. In
1997, the level of recruitment obtained in the French bav of Biscay,
Cantabrian Sea and Galician waters was higher than în 1998, the contrary
being observed m the Celtic Sea. Areas of high concentration of hake
recruits were located at depths between 80 to 200 m and over predominantly muddy bottoms. However, the aggregation patterns were different
on both sides of the bay of Biscay and in the Celtic Sea. The Spanish
patches (Cantabrian Sea and Galicia) were smaller and denser than the
French ones and the low recruitment during 1998 was located in the
same areas but with low density.
In the Cantabrian Sea, the hydrographic results show that the situation of
the hake recruifs coincides with the presence of mesoscale anticyclonic
strucmres. This situation may be explained by ichtyoplankton retention
within the gyres, and subsequent transport of larvae and pre-recruits from
the spawning areas towards these nurseries. The differences between
1997 and 1998 appeared conceming upwelling strength and mesoscale
activity’ (fig. 3). In 1997, the dynamic pattem was formed by a threestripped pattem of: (a) cold upwelling cyclonic nuclei along the continental shelf; (b) warm mesoscale off-shelf anricyclones; and (c) colder and homogeneous off-slope oceanic waters. In 1998, it was configured bv: (a)
well-stratified, warm and low salinim waters; and (b) colder and homogeneous oceanic waters; both (a) and (b) with minor mesoscale features.
Therefore, we suppose that the intense mesoscale acrivity and upwellingin
1997 were the cause of the good recruitment found in the Cantabrian Sea.
On the contrary, the absence of this hydrographic phenomenon could be
the reason for the failure of the 1998 recruitment.
176