126 
Fishery Bulletin 110(1) 
Table 1 
Yearly spawning egg and hatching abundances and life-stage mortality rates used in the Atlantic cod ( Gadus morhua ) age-1 
recruitment hindcasts by program surveys. Marine Resource Monitoring, Assessment, and Prediction (MARMAP) surveys 
occurred from 1977 and 1987, and the U.S. Global Ocean Ecosystems Dynamics (GLOBEC) surveys occurred from 1995 to 1999. 
Survey egg and larval abundances and mortality rates are from Lough et al. (2006) and Mountain and Kane (2010). Pelagic 
juvenile mortality was specified as 6%/d. Demersal juvenile mortality rates were estimated from Equation 7. 
Survey 
and year 
Spawning 
abundance 
(no.xlO 12 ) 
Egg 
mortality 
(%/d) ' 
Hatching 
abundance 
(no.xlO 12 ) 
Larval 
mortality 
(%/d) 
Pelagic 
juvenile 
mortality 
(%/d) 
Demersal 
juvenile 
mortality 
(%/d) 
MARMAP 
1977 
No egg data 
7.209 
8.6 
6.0 
3.00 
1978 
No egg data 
33.395 
16.2 
6.0 
2.27 
1979 
28.817 
17.1 
2.063 
5.5 
6.0 
2.19 
1980 
59.081 
2.7 
33.030 
12.3 
6.0 
2.12 
1981 
58.783 
13.5 
3.214 
5.4 
6.0 
2.54 
1982 
55.048 
19.6 
0.553 
16.0 
6.0 
2.07 
1983 
4.761 
9.5 
0.876 
10.4 
6.0 
1.91 
1984 
3.980 
2.3 
2.644 
9.8 
6.0 
2.26 
1985 
4.935 
4.0 
2.278 
7.6 
6.0 
1.89 
1986 
8.940 
12.3 
0.830 
10.1 
6.0 
2.57 
1987 
8.282 
13.2 
0.607 
10.0 
6.0 
2.04 
GLOBEC 
1995 
22.056 
13.7 
1.269 
8.2 
6.0 
1.78 
1996 
17.186 
12.2 
1.269 
7.1 
6.0 
1.83 
1997 
33.470 
20.4 
0.366 
6.3 
6.0 
1.92 
1998 
11.015 
9.9 
1.520 
5.5 
6.0 
1.81 
1999 
19.304 
15.4 
0.880 
5.1 
6.0 
1.97 
For Georges Bank cod, annual fecundity was esti- 
mated with the NEFSC autumn research survey mean 
lengths-at-age in an exponential fecundity-at-length 
model from fish sampled on Georges Bank in February 
and March of 1999 and 2000 (McIntyre and Hutchings, 
2003). For Georges Bank haddock, annual fecundity 
was estimated by using mean length-at-age from the 
NEFSC autumn research surveys in a fecundity-length 
model based on fish collected on Georges Bank during 
January through March, 1972-73 (Lough et al., 2008). 
In a more recent study by Alonso-Fernandez et al. 
(2009), the autodiametric method was used to estimate 
potential fecundity of cod and haddock on Georges 
Bank. Fish were captured in early March 2006, 2007, 
and 2008. Their derived fecundity-length relationships 
were plotted and compared with the above referenced 
studies and found to be surprisingly close. The cod 
fecundity estimate by Alonso-Fernandez et al. (2009) 
begins to increase slightly for fish 60 cm and lon- 
ger compared with that of McIntyre and Hutchings 
(2003); whereas the Alonso-Fernandez et al. (2009) 
haddock fecundity estimate was slightly lower at all 
sizes than that of Lough et al. (2008). We decided to 
use the McIntyre and Hutchings (2003) and Lough et 
al. (2008) fecundity-length models because the fish 
were captured closer in time to the MARMAP and 
GLOBEC studies. Fecundity estimates at length and 
ages are known to vary annually, especially for cod, 
but this information has not been collected routinely; 
therefore, a single fecundity model was applied for 
each stock under the assumption that fecundity did 
not change significantly. 
To account for differences in egg viability, cod egg 
production was multiplied by a factor of 0.10 for first- 
time spawners, and 0.60 for second-time spawners 
(Trippel, 1998). For haddock, egg production was mul- 
tiplied by 0.033 for first-time spawners and 0.20 for 
second-time spawners (Lough et ah, 2008). For both 
cod and haddock, annual egg production was estimated 
from fecundity at age, summed over ages one to ten. 
Ichthyoplankton-survey-derived egg abundance 
Estimates of hatching abundance from the NEFSC’s 
ichthyoplankton surveys for spawning cod and haddock 
included the MARMAP period 1977-87 (Lough et ah, 
2006, Mountain et al., 2008) and the GLOBEC period 
1995-99 (Mountain et al., 2008). Egg data were lost for 
the 1977 and 1978 seasons. In terms of survey coverage 
during the various sampling periods, the region was 
