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Fishery Bulletin 11 5(4) 
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Figure 4 
Correlation matrix of fecundity and abundance trends 
of spiny dogfish (Squalus acanthias) during 2000-2015. 
Mean fecundity of females by maternal size class, de¬ 
fined in 5-cm increments of stretched total length, is 
correlated with spawning stock biomass (SSB), esti¬ 
mated by using a 3-point moving average (Rago and 
Sosebee 3 ), and with relative abundance estimates 
based on mean number of mature females caught per 
tow during the NOAA Northeast Fisheries Science Cen¬ 
ter spring bottom-trawl survey (Silva, 1993). Fecundity 
for the 4 maternal size classes, 80-84, 85-89, 90-94, 
and 95-99 cm in stretched total length, are labeled as 
Fecundity_80, Fecundity_85, Fecundity_90, and Fecun¬ 
dity _95, respectively. Numerical values denote P-values 
for nonsignificant correlations at an alpha level of 0.05. 
Fecundity data from 2000 to 2002 were obtained from 
Sosebee (2005), data from 2006 to 2009 were obtained 
from Bubley (2010), and data from 2013 to 2015 came 
from this study. 
bryos to parturition. This gestation period is slightly 
longer than that found by Hisaw and Albert (1947; 
20-22 months), slightly shorter than that reported by 
Templeman (1944; 24 months), and similar to that de¬ 
scribed by Bubley (2010; 22-23 months). 
We found a large range in the sizes of ova ready 
for fertilization and a corresponding large size range of 
full-term pups. This was also observed in other stud¬ 
ies and it has been suggested that larger ovarian eggs 
have a larger supply of yolk and would grow into larger 
embryos and would remain in the uterus longer than 
smaller eggs (Ford, 1921; Templeman, 1944; Hisaw and 
Albert, 1947). The embryonic growth rate that we ob¬ 
served was similar to that proposed by Campana et al. 
(2009) and Henderson et al. (2002), that is slow growth 
during the first few months followed by faster growth 
in July through October. Campana et al. (2009) found 
approximately 3-cm-TL embryos by October in year 1, 
and although we are missing October data, our No¬ 
vember average was 6 cm STL. By the following June, 
their samples were approximately 16 cm FL and those 
from the current study averaged 19 cm STL (17.0 cm 
FL). Our results were similar to those of Henderson 
et al. (2002) who observed candled embryos in Decem¬ 
ber through July. The size of full-term embryos in our 
investigation ranged from 19.7 to 30.8 cm STL, which 
is again similar to results of full-term and near-term 
size estimates from other studies in the WNA (Temple¬ 
man, 1944; Hisaw and Albert, 1947; Nammack et al., 
1985). Although many similar size embryos were found 
with internal yolk sacs, they did not appear ready for 
natural parturition. The observation of litters with 
full-term-size individuals and no internal yolks sug¬ 
gests that the internal yolk is consumed before parturi¬ 
tion. This suggestion is in contrast to the suggestion by 
Jones and Geen (1977) that the internal yolk is main¬ 
tained for 2 months past parturition. 
Our data show that parturition is followed closely 
by ovulation and mating and all of these events oc¬ 
cur between January and April, although most com¬ 
monly from February through March. This time frame 
is longer than previously proposed for this geographic 
area (Hisaw and Albert, 1947) and is also different 
from that found in the Gulf of Maine by Bubley (2010), 
who reported parturition before January (October-De- 
cember) followed closely by fertilization. Additionally, 
Campana et al. (2009) found similar results off eastern 
Canada with a 22-24 month gestation period, pupping 
from January through March, and fertilization immedi¬ 
ately after pupping. The timing of parturition observed 
in our study is further corroborated by the finding of 
large numbers of neonate spiny dogfish in February off 
Block Island, Rhode Island, close to our sampling area 
(Sulikowski et al., 2013). 
Studies have shown that there is a greater plas¬ 
ticity in elasmobranch reproduction than previously 
thought (Driggers and Hoffmayer, 2009), although the 
results from studies of dogfish throughout the WNA 
are reasonably consistent. There may be latitudinal 
differences. Bubley (2010), for example, reported re¬ 
sults from the Gulf of Maine that are approximately 
1 month earlier than those that we found for SNE be¬ 
tween Massachusetts and Rhode Island. Essentially all 
the regional studies of spiny dogfish in the WNA have 
a similar gestation period and have only slightly off¬ 
set mating and parturition times. The variation in all 
these studies could be due to latitude or plasticity of 
the reproductive cycle of this species, and could be po¬ 
tentially related to environmental conditions. More re¬ 
gional studies on spiny dogfish and elasmobranchs in 
general are required to determine whether differences 
observed are truly specific to a region or are due to 
plasticity or size (or both), or age of the female (Lom- 
bardi-Carlson et al., 2003; Driggers and Hoffmayer, 
2009; Hoffmayer et al., 2013; Rochowski et al., 2015; 
Taylor et al., 2016). 
The average number of pups from this study, based 
on follicle number, total litter size, and number of 
