220 
NOAA 
National Marine 
Fisheries Service 
Fishery Bulletin 
established 1881 •<?. 
Spencer F. Baird 
First U S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Fish assemblages on the southeastern Brazilian 
Bight, sampled by midwater trawl during spring 
and summer seasons: species composition, 
abundance, and environmental drivers 
Riguell F. Contente (contact author) 
Carmen L. D. B. Rossi-Wongtschowski 
Email address for contact author: riguel@usp.br 
Instituto Oceanografico 
Universidade de Sao Paulo 
Praca Oceanografico, 191 
05508-120, Sao Paulo, SP, Brazil 
Abstract— We provide an overall 
description of the species composi- 
tion and abundance of pelagic fish 
assemblages sampled with midwa- 
ter trawls at depths <100 m in the 
southeastern Brazilian Bight (SBB, 
south-southeastern Brazil) during 
the spring-summer period from 1995 
through 2010. We also investigated 
the effect of 1) 3 water masses, 
the South Atlantic Central Water 
(SACW), Coastal Water (CW), and 
Mixed Water (M), and 2) a set of 
environmental and spatial variables 
on the SBB pelagic fish assemblag- 
es. The aggregations comprising 43 
species, were dominated by highly 
abundant mid-trophic-level schooling 
species. The Argentine anchoita (En- 
graulis anchoita ), rough scad (Tra- 
churus lathami ), Atlantic cutlassfish 
( Trichiurus lepturus ), and Brazilian 
sardinella (Sardinella brasiliensis ) 
were the dominant species by bio- 
mass. They were distributed widely 
over the SBB and occurred in all 
years. Results from multivariate 
analyses indicate that SACW and 
the combination of CW and M af- 
fected the SBB pelagic assemblage 
structure and that each contained 
a specific species grouping, whose 
abundance changed in relation to 
depth within the water column and 
to distance from shore of both SACW 
and CW+M. This pattern is consis- 
tent with the hydrographically com- 
plex structure of the SBB in spring 
and summer. 
Manuscript submitted 1 February 2015. 
Manuscript accepted 23 February 2016. 
Fish. Bull. 114:220-236 (2016). 
Online publication date: 15 March 2016. 
doi: 10. 7755/FB. 114.2.8 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The dramatic increase of human ac- 
tivities in coastal ecosystems world- 
wide has caused unprecedented loss- 
es of biodiversity and changes in the 
structure, resilience, resistance, and 
services of ecosystems (Mollmann 
et al., 2015). Many ecological conse- 
quences of these disturbances remain 
largely unclear because consistent 
ecological data are lacking, especial- 
ly in the tropics. High biodiversity, 
combined with the high diversity of 
habitats and oceanographic dynam- 
ics in tropical and subtropical areas, 
induces complex spatiotemporal pat- 
terns in fish assemblages (Longhurst 
and Pauly, 2007). Such complexity 
makes traditional fishery manage- 
ment based on monospecific popula- 
tion models inadequate and empha- 
sizes the need to control tropical fish- 
eries on the basis of an ecosystem- 
based fisheries management (EBFM) 
perspective (Vasconcellos and Gasal- 
la, 2001; Curtin and Prellezo, 2010). 
The first step toward achievement 
of strong EBFM is to know how fish 
species respond to the oceanographic 
environment and its dynamism (Lon- 
ghurst and Pauly, 2007; Curtin and 
Prellezo, 2010; Harding et al., 2011; 
Litz et al., 2014). 
The largest fish aggregations (de- 
fined here as a large multispecific 
group of fishes that gather together, 
for behavioral or other reasons) on 
continental shelves are generally 
dominated by small pelagic fish spe- 
cies, such as sardines and anchovies, 
that are usually short-lived, plank- 
tivorous fishes frequently associated 
with areas of high productivity (Bro- 
deur et al., 2005; Harding et al., 2011; 
Litz et al., 2014). These species are 
ecologically and economically impor- 
tant, exerting bottom-up, top-down, 
and wasp-waist control in shelf food 
webs (Cury et al., 2000; Speckman 
et al., 2005) and supporting valuable 
fisheries (Vasconcellos and Gasalla, 
2001). The presence and abundance 
of small pelagic fishes are particu- 
larly sensitive indicators of chang- 
ing oceanographic and climatic con- 
ditions, migrating quickly into their 
preferred habitat or responding with 
pronounced recruitment fluctuations 
over relatively short time intervals 
(Brodeur et al., 2003; Brodeur et al., 
2005; Longhurst and Pauly, 2007). 
In spite of being a western bound- 
ary system, the large marine ecosys- 
tem of the southeast South Ameri- 
can shelf (SSAS; sensu Bisbal, 1995) 
presents productivity hotspots com- 
parable to those of eastern bound- 
