517 
National Marine 
Fisheries Service 
NOAA 
Fishery Bulletin 
ft- established in 1881 
Spencer F. Baird 
First U S Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Seasonal and regional variation in egg size of the 
Argentine anchoita (Engraulis anchoita) in the 
southeastern Brazilian Bight 
Email address for contact author: delfaveroiana@gmail.com 
Abstract —Eggs of the Argentine an¬ 
choita (Engraulis anchoita) are very 
abundant and frequently collected in 
research ichthyoplankton tows along 
the southern-southeastern Brazilian 
coast. The commercial exploitation of 
Argentine anchoita has also recently 
begun in southern Brazil. Therefore, 
there is a need for a better under¬ 
standing of the population structure 
and dynamics of this species in or¬ 
der to manage the fishery for this 
species. Our objective was to deter¬ 
mine seasonal and regional variabil¬ 
ity in the size of eggs of Argentine 
anchoita in the southeastern Brazil¬ 
ian Bight (SBB). Because there are 
no physical barriers in the ocean, 
defining stock limits for fish popula¬ 
tions is difficult, particularly for a 
semimigratory species such as the 
Argentine anchoita. Eggs from the 
south of the SBB were larger than 
those from the north, indicating that 
eggs from the northern Santa Marta 
Cape region probably belong to the 
honaerense stock. Also, eggs collected 
during the winter were larger than 
those collected during the summer. 
This difference in egg size may be 
due to either 1) larger adults com¬ 
ing from the south and spawning in 
or closer to the area sampled during 
winter, or 2) an adaptive response of 
spawning females to the changes in 
the abiotic conditions or 3) a combi¬ 
nation of these 2 features. 
Manuscript submitted 27 October 2016. 
Manuscript accepted 15 August 2017. 
Fish. Bull. 115:517-531 (2017). 
Online publication date: 1 September 2017. 
doi: 10.7755/FB. 115.4.8 
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. 
Jana M. del Favero (contact author) 1 - 3 
Mario Katsuragawa 1 
Fabricio S. C. Oliveira 2 
Nayara C. Tannure 1 
M. L. Zani-Teixeira 1 
Jefferson T. Turner 3 
1 Institute Oceanografico 
Universidade de Sao Paulo 
Pra^a do Oceanografico, 191 
05508-120, Sao Paulo, SP, Brazil 
2 Institute de Oceanografia 
Universidade Federal do Rio Grande 
Avenida Italia km 8 
96203-900, Rio Grande, RS, Brazil 
3 School for Marine Science and Technology 
University of Massachusetts Dartmouth 
706 S. Rodney French Boulevard 
New Bedford, Massachusetts 02744-1221 
Most marine fish eggs are identi¬ 
fied by their size, shape and pigment 
characters, but many newly fertilized 
eggs are unpigmented and therefore 
egg diameter is the most distinguish¬ 
ing feature (Bagenal, 1971). Auto¬ 
mated identification of fish eggs, 
based on their size and shape (Fa¬ 
vero et al., 2015) is possible; how¬ 
ever, egg size varies among species, 
among populations, and within pop¬ 
ulations of the same species owing 
to temporal, spatial, biological, and 
environmental factors (e.g., Phonlor, 
1984; Wootton, 1990; Chambers and 
Waiwood, 1996; Llanos-Rivera and 
Castro, 2004). In addition to identi¬ 
fication of fish eggs, it is important 
to understand variation in egg sizes 
because larger eggs typically hatch 
into larger larvae with the possibility 
of conferring a higher survival poten¬ 
tial on the resulting offspring (e.g., 
Blaxter and Hempel, 1963; Blaxter 
and Hunter, 1982; Marteinsdottir 
and Able, 1992). 
The Argentine anchoita (Engrau¬ 
lis anchoita) (Engraulidae: Clupe- 
iformes) is a small pelagic fish, which 
is important as a secondary consum¬ 
er near the bottom of the food chain, 
and is an essential prey for other 
fish species, marine mammals, and 
seabirds (Castello, 2007). It is eco¬ 
nomically important to the Argentine 
and Uruguayan fishery fleets (FAO, 
2014), and exploitation of Argen¬ 
tine anchoita has recently begun in 
southern Brazil (Carvalho and Cas¬ 
tello, 2013). This species is widely 
distributed over the continental shelf 
of the southwest Atlantic, from Vito¬ 
ria, Brazil (20°S) to Gulf San Jorge, 
Argentina (48°S) (Castello, 2007). 
There are 3 distinct stocks: the pa- 
tagonic (48-41°S), the honaerense 
