Contente and Rossi-Wongtschowski: Fish assemblages in the southeastern Brazilian Bight 
231 
(57% of fitted, 4.4% of total variation) 
dbRDAI 
H 
60 
Figure 4 
The first 2 axes from the distance-based redundancy analysis (dbRDA) that correlate the pelagic fish assem- 
blage data collected during the spring-summer ECOSAR IV- VII cruises with (A) the species groups or species 
and (B) the explanatory variables (from the fitted model). Z)S=distance from shore, Z a =mean depth of the fish 
aggregation. Data from ECOSAR IV-VII cruises (63 tows) are pooled because there was no interannual effect 
on the assemblages. Samples were taken either from the South Atlantic Central Water (circles) or from the 
combination of the Coastal Water and Mixed Water (triangles). Group A and B were defined in cluster analy- 
ses (Fig. 3) and showed a Spearman correlation coefficient |r SP | -0-2 with the axes. Group C species did not 
show clear association with a particular water mass; therefore, only those Group C species with correlations 
>0.2 with either axis are plotted. Percentage explained by the axis (fitted) and total variation explained by the 
model are provided on the axes. 
SBB and other areas of the SSAS. The Argentine an- 
choita forms large schools and is the dominant species 
in standing stocks of pelagic fishes and larval assem- 
blages in the inner SBB (depths <100 m; this study; 
Katsuragawa et al., 2006), outer SBB (depths >100 m; 
Madureira et al., 2005), southern Brazilian shelf (Mel- 
lo et al., 1992; Castello, 1998; Madureira et al., 2005), 
and coastal waters of Argentina (Hansen et ah, 2001), 
supporting the idea that it is a keystone species of the 
SSAS (Bisbal, 1995; Castello, 1998; Hansen et ah, 2001). 
Catches by industrial purse-seine fleets or during pre- 
vious scientific surveys indicate that large schools of 
rough scad and Atlantic chub mackerel are common 
from the SBB to northern Argentina (Mello et ah, 1992; 
Haimovici e ah, 1994; Saccardo and Katsuragawa, 1995; 
Castro Hernandez and Santana Ortega, 2000; Jauregui- 
zar et ah, 2006). The rough scad constitutes up to 85% 
of the standing stock of carangid larvae in the SBB 
(Katuragawa et ah, 2006). Large bycatches of American 
coastal pellona and Atlantic cutlassfish are common in 
bottom trawl fisheries in the SBB (e.g., Paiva-Filho and 
Schmiegelow, 1986; Bernardes Junior et ah, 2011). The 
Brazilian sardinella is the most abundant fish in indus- 
trial purse-seine catches in the SBB (Vasconcellos and 
Gasalla, 2001), where its larvae are widely distributed 
(Katsuragawa et ah, 2006). 
The massive schools of flying gurnard juveniles de- 
tected in the water column were an uncommon and 
previously unreported phenomenon because this fish, 
which is morphologically adapted for living on soft bot- 
toms (i.e. , it has a relatively dorsoventrally flattened 
body and thoracic-placed pelvic fins to “walk” and for- 
age over substrate; Sazima and Grossman, 2005), usu- 
ally is captured in somewhat smaller numbers (gener- 
ally <1% of the total catch; e.g., Wood et ah, 2009) or 
is observed in small groupings (of approximately 30- 
50 individuals) foraging on soft bottoms (Sazima and 
Grossman, 2005). Shoaling and crowding behavior has 
been reported for related species (e.g., the Oriental fly- 
ing gurnard \Dactyloptena orientalis]; Noble, 1966) on 
the bottom but not for such species in the pelagic habit. 
It has been speculated that flying gurnard juveniles of 
such species cluster together in the water column to 
feed opportunistically on transitory and dense patches 
of zooplankton commonly present in spring and sum- 
mer (Cordeiro 7 ; Lopes et ah, 2006b). 
The aggregation structure in the SBB differed from 
the structure of aggregations in the pelagic zone off the 
7 Cordeiro, C. A. M. 2014. Personal commun. Departamen- 
to de Ciencias do Mar, Univ. Federal de Sao Paulo, Santos, 
Brazil. 
