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Fishery Bulletin 114(2) 
ric locations of these water masses change seasonally 
(Castro and Miranda, 1998; Ciotti et al., 2014). Like a 
typical subtropical shelf ecosystem, the SBB exhibits a 
strong seasonal signal of stratification (Castro, 2014) 
and pelagic fertilization (Lopes et al., 2006a). 
In autumn and winter, the increased frequency and 
strength of southwest winds (i.e. , downwelling-favor- 
able winds) due to recurrent passages of atmospheric 
frontal systems (Ciotti et al., 2014) favor strong verti- 
cal homogeneity, the distance of ~86 km of the SACW 
from shore, the predominance of the CW and Tropical 
Water on the SBB, and, eventually, the northward dis- 
placement of the low-salinity and nutrient-rich Rio de 
La Plata plume up to the southern part of the SBB 
(Ciotti et al., 2014). In contrast, in spring and summer, 
both the prevailing northeast winds (Ciotti et al., 2014) 
and the higher frequency of cyclonic meanders of the 
Brazil Current (Campos et al., 1995) favor cross-shelf 
SACW intrusions toward the coast. Also in spring and 
summer, continental runoff generally is higher than 
that during other seasons, and increased runoff may 
make the CW expand offshore and occur nearer the 
ocean surface on the SBB (Lopes et al., 2006a). Such 
processes lead to strong vertical and geographic vari- 
ability in temperature and salinity because of the pres- 
ence of 2 markedly different water masses (CW and 
SACW) in the spring and summer (Castro, 2014; Ciotti 
et al., 2014; Fig. 1). In spite of this stratification, the 
interface zones between tMi CW, the SACW, and the 
offshore Tropical Water, in association with natural lo- 
calized mixing, produce a Mixed Water (M) mass (Cas- 
tro, 2014). 
This spring-summer oceanographic structure (Cas- 
tro, 2014) increases oceanic fertilization, pelagic pro- 
ductivity (Lopes et al., 2006a), and water column sta- 
bility, and all such conditions synergistically enhance 
the larval survival of many fish species that spawn 
at this time, including important commercial species, 
such as the Brazilian sardinella (Sardinella brasilien- 
sis ) (Katsuragawa et al., 2006). Therefore, it is expected 
that the structure of the pelagic fish assemblage would 
respond to these typical spring-summer water masses 
and to their spatial variability. 
The SBB produces approximately 50% of Brazil’s 
marine landings (MPA 1 ), and the Brazilian sardinella 
is the main species landed (UNIVALI 2 ). Despite the 
ecological and economic importance of the SBB, our 
understanding of the ecological patterns of its shal- 
low (depths <100 m) pelagic aggregations is still fairly 
limited because of 1) the limited number of surveys 
with pelagic trawls in comparison with other sampling 
gears, such as bottom trawls (e.g., Rocha and Rossi- 
Wongtschowski, 1998; Rossi-Wongtschowski et al., 
1 MPA (Ministerio da Pesca e Aquicultura). 2011. Boletim 
estatistico da pesca e aquicultura 2011, 59 p. MPA, Brasilia, 
Brazil. [Available at website.] 
2 UNIVALI (Universidade do Vale do Itajai). 2011. Boletim 
estatistico da pesca industrial de Santa Catarina — Ano 2010, 
59 p. Centro de Ciencia tecnologicas da Terra e do Mar, 
UNIVALI, Itajai, Brazil. [Available at website.] 
2008) — a situation that is a general one for the whole 
SSAS (e.g., Haimovici et al., 1994; Jaureguizar et ah, 
2006), and 2) the focus of most pelagic trawl surveys on 
a single species (e.g., Brazilian sardinella; Johannes- 
son 3 ; Rijavec and Amaral 4 ; Castello et al., 1991). These 
biases limit our understanding of the functioning of 
this large regional-scale (<1000 km) ecosystem and its 
changes due to climate changes and fisheries, therefore 
limiting our ability to implement strong EBFM. 
During the Program of Assessment of the Sustain- 
able Potential of the Living Resources in the Exclusive 
Economic Zone (REVIZEE), acoustic surveys and pe- 
lagic trawls were conducted off the SBB at depths >100 
m (Madureira et al., 2005; Soares et al., 2005). Between 
1995 and 2010, this sampling procedure was adopted 
to sample pelagic aggregations and the oceanographic 
environment in the SBB at depths <100 m during 7 
cruises for the Program ECOSAR (abbreviation trans- 
lated as: Prospecting to investigate sardine biomass 
by acoustic methods). The checklist of species from all 
of these cruises (Rossi-Wongtschowski et ah, 2014) and 
the pattern of species abundance for ECOSAR II and 
III cruises (Soares et al., 2005) are already available. 
In this study, we synthesized the data of ECOSAR 
III — VII cruises conducted in spring and summer 1) to 
provide an overall description of the species composi- 
tion and abundance of the fish aggregations in the SBB 
during the spring and summer and 2) to investigate 
how these aggregations respond to the typical spring- 
summer water masses (CW, SACW, and M) and to a set 
of environmental and spatial covariates to such water 
masses. 
Materials and methods 
Sampling procedures 
Fish and oceanographic data for this study were ob- 
tained in the spring or summer between 1995 and 2010 
during the ECOSAR III, IV, V, VI and VII cruises on 
board the RV Atldntico Sul of the Federal University of 
Rio Grande. The search for fish aggregations was con- 
ducted over a pre-established grid during the day and 
night, at a mean speed of 5.1 m/s (10 knots), over a pe- 
riod lasting from 12 to 18 days. A grid of parallel tran- 
sects was used, with a distance of 37 km between them. 
The grid spanned from the Cabo Frio (Rio de Janeiro, 
north limit) to Cabo de Santa Marta (Santa Catarina, 
south limit) (Fig. 1) and included depths from 20 to 102 
3 Johannesson, K. A. 1975. Relatorio preliminar das obser- 
vances acusticas quantitativas sobre tamanho e distribuigao 
dos recursos de peixes pelagicos ao largo da costa sul do Bra- 
sil. Programa de Pesquisa e Desenvolvimento Pesqueiro do 
Brasil Serie Documentos Tecnicos 10, 27 p. 
4 Rijavec, L., and J. C. Amaral. 1977. Distribuigao e abun- 
dancia de peixes pelagicos na costa sul e sudeste do Brasil: 
(resultados da pesquisa com ecointegrador) 2 cruzeiros. Pro- 
grama de Pesquisa e Desenvolvimento Pesqueiro do Brasil 
Serie Documentos Tecnicos 24, 55 p. 
