232 
Fishery Bulletin 1 14(2) 
SBB (i.e., at depths >100 m) as characterized during 
the REVIZEE midwater trawl surveys (Soares et al., 
2005). Aggregations at depths of approximately 100 m 
were composed mainly of Argentine anchoita (89% of 
the total catch), followed by American coastal pellona 
(7%), Atlantic cutlassfish (7%), white snake mackerel 
(7%), and rough scad (1%). Therefore, these aggrega- 
tions were fairly similar to those in the SBB at depths 
<100 m. In depths of 100-200 m , there was a strong 
shift in species abundance, and the aggregations there 
were primarily composed of a mesopelagic lightfish 
species ( Maurolicus stehmani) (60% of the total catch), 
together with the Argentine anchoita (18%), striped 
codiet (Bregmaceros cantori\ 7%), and Atlantic cutlass- 
fish (4%). 
Over the shelf break of the SBB (at depths of 200- 
800 m), aggregations contained virtually no Clupe- 
iformes (Soares et al., 2005) and consisted mostly of 
M. stehmani (96% of the total catch), which were asso- 
ciated with a few species (e.g., Atlantic cutlassfish, and 
the largescale lizardfish [Saurida brasiliensis ]). Such a 
replacement of Clupeiformes by mesopelagic fishes in 
the SBB is a typical pelagic shelf-slope gradient world- 
wide (e.g., Brodeur et al., 2003). 
The aggregations found in the SBB were different 
from those that were hydroacoustically detected in a 
similar depth range (<100 m) off the central and north- 
eastern coasts of Brazil. In central Brazil, they were 
composed of massive schools of the balloonfish ( Diodon 
holocanthus [Madureira et al., 2004]) or of multiple 
species of triggerfishes (i.e., the unicorn filefish ( Aluter - 
us monocei'os ), gray triggerfish, queen triggerfish [Bati- 
stes vetula ], and ocean triggerfish [Canthidermis suffla- 
men]). In northeastern Brazil, they were many fewer in 
number, compared with aggregations in southeastern 
Brazil, and they were composed of Myctophidae and 
Bothidae and did not contain schools of Clupeiformes 
(Vaske et al. 8 ). In addition to the differences in efforts 
and spatiotemporal scales of sampling, these differ- 
ences between the aggregations found in our study 
and those reported for the northeastern Brazil are 
most likely related to the pronounced zoogeographical 
contrast in fish fauna between the northeastern and 
southeastern coasts of Brazil (Joyeux et al., 2001). 
Most of the records for tows carried out in areas 
identified as M most likely represented areas of mix- 
ing between CW and SACW, instead of between CW or 
SACW and Tropical Water. Tows conducted in M were 
carried out near the shoreline (mean distance: 37.2 
km [32.6]), where the influences of CW and SACW are 
stronger than that of Tropical Water, which is located 
farther offshore ( — 80 km from the shoreline) during 
spring and summer (Castro, 2014). 
Our results reveal that there were 2 groupings of 
8 Vaske, T., Jr., R. .P. Lessa, A. Monteiro, J. L. Bezerra, Jr, A. 
C. B. Ribeiro, L. Yokota, K. C. Moura, K. Lopez, and J. P. Fir- 
mino. 2005. Programs de Prospecgao Acustica do Nordeste 
do Brasil (Levantamento da fauna com rede de meia agua). 
REVIZEE Relatorio Final, 54 p. 
species that showed high occurrence and attained the 
highest biomass in specific water masses in the SBB in 
the spring-summer season: 1) the grouping that was 
strongly related to SACW and was composed mostly 
of Argentine anchoita, Atlantic cutlassfish, rough scad, 
piquitinga anchovy, white snake mackerel, and Atlantic 
chub mackerel and 2) the grouping that was formed 
mostly by Brazilian sardinella, flying gurnard, false 
pilchard, American coastal pellona, Atlantic thread her- 
ring, castin leatherjacket, and Atlantic bumper ( Chlo - 
roscombrus chrysurus) and was strongly associated 
with CW and areas of mixing between CW and SACW. 
The peak in biomass of each grouping followed the 
variation in location of their preferred water masses 
in relation to depth in the water column and distance 
from shore. The biomass of SACW-related assemblages 
reached its peak in deeper (Fig. 4) nearshore areas, and 
the biomass of CW+M-related assemblages reached its 
peak in waters farther offshore (Fig. 4), more surface 
layers. Such a pattern is consistent with the spring- 
summer, complex hydrography of the SBB, and this 
hydrography generates spatial variations in tempera- 
ture and salinity. Cyclonic eddies and meanders of the 
Brazil Current on the SBB are stronger in the spring 
and summer (Campos et al., 1995). Additionally, in 
this season, the large-scale high-pressure center in the 
South Atlantic makes winds blow from the northeast, 
resulting in stronger wind stress along the shore that 
leads to a surface offshore Ekman transport (Rodrigues 
and Lorenzetti, 2001). Both processes result in wide in- 
trusion of the SACW frontal zone toward the inshore 
zones and in its persistence in deeper waters of the 
SBB just below the CW (Campos et al., 1995). Such 
a setting is more conspicuous near the shore between 
Cabo Frio and Sao Sebastiao Island (Ciotti et al., 2014). 
Additionally, in the spring and summer, increased con- 
tinental runoff may cause the CW to expand offshore 
and nearer the ocean surface on the SBB (Lopes et al., 
2006a). 
The consistent association of groups of species to 
specific water masses supports evidence that their life 
cycles are intimately tied to the typical water masses 
in the spring and summer at the SBB (Katsuragawa et 
al., 2006). Most of these species have a marked spawn- 
ing activity in the spring and summer in the area (Kat- 
suragawa et al., 2006), when the availability of plank- 
tonic food and the standing stock were at their highest 
levels (Lopes et al., 2006b). The growth of pelagic fish 
larvae occurs at a higher rate in specific temperature 
ranges, and those ranges differ among species (e.g., 
Matsuura, 1998). Therefore, this observed fidelity to 
habitat (water mass) may ensure suitable food supply 
within optimal temperature conditions for higher lar- 
val growth, survival, and recruitment, in turn, ensuring 
reproductive success (Matsuura, 1998; Jablonski and 
Legey, 2004). For example, the body condition of larvae 
of Argentine anchoita was highest in the SACW up- 
wellings (Clemmesen et al., 1997). Results from studies 
based on observational data (Matsuura, 1998; Jablon- 
ski and Legey, 2004) and simulated data (Dias et al., 
