473 
National Marine 
Spencer F. Baird /*' V 
Fisheries Service 
Fishery Bulletin 
First U S. Commissioner 1.. 9 
NOAA 
fb* established in 1881 •<?. 
of Fisheries and founder 
of Fishery Bulletin 
Gestation period and pupping seasonality of 
female spiny dogfish (Squalus acanthias ) off 
southern New England 
Email address for contact author: Iisa.natanson@noaa.gov 
Abstract— Recently, it has been sug¬ 
gested that spiny dogfish (Squalus 
acanthias) in the western North At¬ 
lantic Ocean have a shorter gesta¬ 
tion period than the widely cited 
2 years, have an asynchronous re¬ 
productive cycle, and carry pups 
in various stages of development. 
Mature female spiny dogfish were 
collected monthly from July 2013 
through June 2015 to confirm gesta¬ 
tion period and pupping seasonality 
off southern New England, and data 
on 2545 embryos from 622 females 
were obtained. Recent postpartum 
females and females with candled 
embryos appeared from January 
through April indicating parturition 
that was followed closely by mating. 
Vitellogenesis is concurrent with 
embryo growth, and therefore ova 
are ready for fertilization immedi¬ 
ately after pupping. Visible embryos 
were observed in June, and growth 
continued until the external and in¬ 
ternal yolks were absorbed and the 
umbilical scar was partially healed. 
Gestation period was approximately 
23 months. No individual was ob¬ 
served with first and second year 
embryos. Average fecundity per fe¬ 
male was estimated on the basis of 
the largest group of oocytes (5.3), 
free-living embryos (4.3), and total 
embryos (candled and free-living) 
(4.5). These values are similar to 
those of previous studies, but aver¬ 
age fecundity by maternal size class 
has decreased from that of previous 
studies and is negatively correlated 
with spawning stock biomass, which 
provides supporting evidence for 
density dependent fecundity. 
Manuscript submitted 30 September 2016. 
Manuscript accepted 24 July 2017. 
Fish. Bull. 115:473^83 (2017). 
Online publication date: 8 August 2017. 
doi: 10.7755/FB.115.4.4 
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. 
Lisa J. Natanson (contact author ) 1 
Camilla T. McCandless 1 
Kelsey James 2 
John Hoey 1 
1 Northeast Fisheries Science Center 
National Marine Fisheries Service, NOAA 
28 Tarzwell Drive 
Narragansett, Rhode Island 02882 
2 Department of Biological Sciences 
University of Rhode Island 
120 Flagg Road 
Kingston, Rhode Island 02881 
Spiny dogfish (Squalus acanthias) 
occur in the western North Atlan¬ 
tic (WNA) Ocean from Labrador, 
Canada, to Florida, United States, 
but are most abundant from Nova 
Scotia, Canada, to Cape Hatteras, 
North Carolina (Collette and Klein- 
MacPhee, 2002). Seasonal migra¬ 
tions occur northward in the spring 
and summer and southward in the 
fall and winter (Hisaw and Albert, 
1947; Jensen, 1965; McMillan and 
Morse, 1999). Conventional and sat¬ 
ellite tagging studies also suggest 
some localized movement occurs 
within these large-scale seasonal 
migrations, for instance, a southern 
and a northern group overlap in the 
Gulf of Maine (Campana et al. 1 ; and 
1 Campana, S. E., A. J. F. Gibson, L. 
Marks, W. Joyce, R. Rulifson, and M. 
Dadswell. 2007. Stock structure, life 
history, fishery and abundance indices 
for spiny dogfish (Squalus acanthias) in 
Atlantic Canada. Canadian Science Ad¬ 
visory Secretariat, Res. Doc. 2007/089, 
133 p. [Available from website.] 
references within) and off southern 
New England (SNE) (Carlson et al., 
2014). 
The fishery on mature female 
spiny dogfish in the 1990s led to 
a significant reduction in female 
spawning stock biomass in the WNA 
(Rago and Sosebee, 2009), because 
the resulting size-selective mortality 
exceeded the growth and reproduc¬ 
tive rates of this iGselected species. 
Additionally, the size at first maturi¬ 
ty for female spiny dogfish declined 
by 10 cm in length between the late 
1980s and the late 1990s and may 
have been a result of this reduc¬ 
tion in female spawning stock bio¬ 
mass (Sosebee, 2005). However, the 
size-selective nature of the fishery 
left the abundance of the generally 
smaller male spiny dogfish relatively 
unaffected (Rago and Sosebee, 2009). 
Recent updates on the status of 
spiny dogfish show that the female 
spawning stock biomass has been 
rebuilt, the population is no longer 
overfished, and overfishing is not oc- 
