404 
Fishery Bulletin 115 ( 3 ) 1 
o 14 
^ 12 
T3 
£i° 
o> o 
CD ° 
□ □ □ □ 
• Model with age data 
□ Model with total length data 
2005 2006 2007 2008 2009 2010 2011 2012 2013 
Year 
Figure 6 
Reduction in egg production (%) caused by female 
Argentine hake ( Merluccius hubbsi) that would skip 
spawning during the spawning peak of the Patagonian 
stock during the period 2005-2013. The black circles 
indicate percentages obtained from the model in which 
age was used, and the open squares indicate percent- 
ages from the model in which total length was used. 
Discussion 
The interruption in gonad maturation during the re- l 
productive cycle has been reported in different fish 
populations for over 40 years (Rideout et al., 2005), i 
but more recently, SS has been recognized as poten- 
tially having important implications for the reproduc- 
tive output of a population (Livingston et al., 1997; 
Trippel, 1999; Rideout et al., 2000). Clearly, there is 
a negative effect on egg production when a proportion 
of the adult fish does not spawn during an entire year. 
Therefore, failure to consider females that skip spawn- } 
ing may lead to an overestimation of the actual num- 
ber of spawning individuals and affect calculations of j 
reproductive potential of a stock. 
In the case of Argentine hake, data collected from 
the primary reproductive area of the Patagonian stock 
reveal the presence of nonreproductive adult females 
during the spawning season (Macchi et al., 2004; Pa- 1 
jaro et al., 2005). Recently, Macchi et al. (2016) re- i 
ported that of the 3 types described for the process of 
skipped spawning (retaining, reabsorbing, and resting) 
1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 
Age (years) Age (years) Age (years) 
Figure 7 
Egg production by age class in one spawning event, estimated for female Argentine hake ( Merluccius hubbsi) collected 
from the Patagonian stock off Argentina in January during the spawning peak of 2005-2013. The black area represents 
the fraction by which the egg production was reduced by females that would skip spawning, and the gray area indicates 
the actual egg production. 
