396 
National Marine 
Fisheries Service 
NOAA 
Abstract — We analyzed the effect of 
skipped spawning on the estimates 
of length and age at maturity and 
on the reproductive potential of Ar- 
gentine hake ( Merluccius hubbsi) 
from the Patagonian stock during 
the spawning peaks between 2005 
and 2013. The length at first ma- 
turity increased by 2-3 cm in total 
length (TL), and the age at maturity 
increased by 0.27-0.88 years when 
the proportion of females that would 
skip spawning was incorporated in 
the relationships. In addition, the 
slopes of the models decreased, sug- 
gesting that all individuals reach 
sexual maturity at a greater size 
and age than those estimated with 
the traditional criterion for matu- 
rity, which does not consider skipped 
spawning because fish in the resting 
stage are classified as mature. The 
reduction in egg production caused 
by skipped spawning ranged be- 
tween 3.56% and 12.12%, when we 
used the maturity models with age 
data, or between 2.70% and 6.80%, 
when we used the models with 
TL data. Females that would skip 
spawning were mainly specimens 
with sizes between 40 and 50 cm TL, 
and most belonged to the age class 
of 3-year-old fish. 
Manuscript submitted 26 October 2016. 
Manuscript accepted 30 May 2017. 
Fish. Bull. 115:396-407 (2017). 
Online publication date: 13 June 2017. 
doi: 10.7755/FB.115.3.9 
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. 
Fishery Bulletin 
^ established in 1881 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Effects of skipped spawning on the reproductive 
potential of Argentine hake {Merluccius hubbsi ) 
Gustavo J. Macchi 1 - 2 (contact author) 
Karina Rodrigues 1 ' 2 
Marina V. Diaz 12 
Maria I. Militelli 1 2 
Email address for contact author: gmacchi@inidep.edu.ar 
1 Consejo Nacional de Investigaciones Cientfficas y Tecnicas (CON ICED 
Instituto de Investigaciones Marinas y Costeras (IIMyC) 
Rodriguez Pena 4002-4100 
B7602GSD Mar del Plata 
Buenos Aires, Argentina 
2 Instituto Nacional de Investigacion y Desarrollo Pesquero (INIDEP) 
Paseo Victoria Ocampo Nro. 1 
B7602HSA Mar del Plata 
Buenos Aires, Argentina 
One of the main assumptions in fish- 
ery assessments for iteroparous fish 
species is that after spawning for the 
first time, i.e., after reaching matu- 
rity, these species reproduce annu- 
ally. Nevertheless, failure to spawn 
in consecutive years has been ob- 
served in many species, a phenome- 
non known as skipped spawning (SS) 
(Rideout et al., 2005). In general, the 
hypotheses proposed to explain the 
cause of SS are associated with feed- 
ing deficiencies that decrease energy 
storage before spawning. Such feed- 
ing deficiencies may leave the fish in 
such a poor nutritional condition that 
they may not have sufficient energy 
to support egg production in consec- 
utive years (Dutil, 1986; Holmgren, 
2003; Jprgensen et al., 2006; Rideout 
et al., 2006; Rideout and Tomkiewicz, 
2011). Failure to consider SS in the 
reproductive output of a stock could 
result in an overestimation of spawn- 
ing stock biomass and reproductive 
potential (Rideout and Tomkiewicz, 
2011). Despite the influence of the 
SS phenomenon in the estimation of 
total egg production, this influence 
has rarely been considered in fishery 
assessments (Rideout et al., 2005). 
The Patagonian stock of Argentine 
hake ( Merluccius hubbsi), distributed 
from 41°S to 55°S at depths between 
50 and 500 m, is one of the most im- 
portant fishery resources for Argen- 
tina; the total annual catch reported 
for 2015 was approximately 260,000 
metric tons (Ministerio de Agroin- 
dustria 1 ). This stock is assessed an- 
nually through virtual population 
analysis with an age-structured mod- 
el with spawning stock biomass as a 
biological reference point. The Argen- 
tine hake from the Patagonian region 
is a batch spawner with indetermi- 
nate annual fecundity; it reproduces 
from November to April and peak 
spawning occurs in January (Macchi 
et al., 2004). Recently, it was reported 
that 6-22% of female Argentine hake 
from Patagonian waters would skip 
spawning and remain unproductive 
during the spawning peak (Macchi et 
1 Ministerio de Agroindustria. 2015 De- 
sembarques de capturas marftimas to- 
tales — por especie y flota. Subsecretaria 
de Pesca y Acuicultura, Secretaria de 
Agricultura, Ganaderia y Pesca, Min- 
isterio de Agroindustria, Buenos Aires, 
Argentina. [Available from website, ac- 
cessed October 2016.] 
