4 74 
Fishery Bulletin 11 5(4) 
curring (Rago and Sosebee 2 ’ 3 ). Sustainability of this 
fishery is directly linked to the reproduction of adult 
females and an overabundance of males may, in fact, 
be detrimental to recruitment (Rago 4 ). Despite success 
in rebuilding the female spawning stock biomass and 
the increased efficiency in use of the resource (a de¬ 
crease in the ratio of discards to landings), spiny dog¬ 
fish management still faces many challenges. 
Numerous studies have been conducted on the re¬ 
production of the spiny dogfish worldwide (Kaganovs- 
kaia, 1937; Yamamoto and Kibezaki, 1950; Jensen, 
1965; Ketchen, 1972; Hanchet, 1988; Avsar, 2001; 
Chatzispyrou and Megalofonou, 2005; Di Giacomo et 
al., 2009; Capape and Reynaud, 2011; GraCan et ah, 
2013). Studies specific to the WNA have suggested that 
there is an 18-25 month gestation period, which may 
depend on water temperature (Templeman, 1944; Hi- 
saw and Albert, 1947; Bigelow and Schroeder, 1953; 
Nammack et ah, 1985; Campana et ah, 2009; Bubley, 
2010, Bubley et al., 2013). Although these reports all 
suggest a similar gestation period, in most cases the 
time periods over which the research was conducted 
were not adequate to fully support these conclusions. 
Many of these studies were dependent either on sam¬ 
ples that were collected over only a few months or on 
sporadic partial-year sampling (Templeman, 1944; Hi- 
saw and Albert, 1947; Nammack et ah, 1985; Campana 
et ah, 2009). Nammack et al. (1985); for example, data 
were collected between Cape Fear, North Carolina, 
and the Gulf of Maine between November and May to 
characterize the reproduction of the spiny dogfish off 
the northeastern United States. Furthermore, these 
studies suggested a similar pattern for the gestation 
period that had been described by Jones and Geen 
(1977) for spiny dogfish in the Pacific Ocean, a spe¬ 
cies that has now been identified as a separate spe¬ 
cies with different life history parameters: the Pacific 
spiny dogfish (Squalus suckleyi) (Campana et al., 2006; 
Ebert, 2010). More recently, Campana et al. (2009) de¬ 
scribed a 2-year gestation period for spiny dogfish in 
the WNA off of the Eastern Coast of Canada, however, 
as in other studies, this conclusion was based on lim¬ 
ited sampling between June and October. Nevertheless, 
a 2-year gestation period is currently used in the stock 
assessment process for WNA spiny dogfish. Studies of 
shark reproduction, in general, have shown substan¬ 
tial latitudinal variation, as well as mixed gestational 
periodicity in a species in the same area (Driggers and 
Hoffmayer, 2009; Hoffmayer et al., 2013; Taylor et al., 
2 Rago, P., and K. Sosebee. 2014. Update of landings and 
discards of spiny dogfish in 2014, 19 p. [Available from the 
Mid-Atlantic Fishery Management Council, 800 North State 
St., Ste. 201, Dover, DE 19901.] 
3 Rago, P., and K. Sosebee. 2015. Update on the status of 
spiny dogfish in 2015 and projected harvest at the Fmsy 
proxy and Pstar of 40%, 65 p. Mid-Atlantic Fishery Manage¬ 
ment Council, Dover, DE. [Available from website.] 
4 Rago, P. 2015. Spiny dogfish: New England’s favorite spe¬ 
cies. Presentation for the Cape Cod Commercial Fisherman’s 
Alliance in Chatham, MA, on 2 March 2015. [Available 
from website, accessed October 2015.] 
2016). In particular, it has been suggested that there 
are regional differences in the reproductive cycles in 
the WNA spiny dogfish population (Sulikowski et al. 5 ). 
Specifically these authors suggest that regional asyn¬ 
chronies in reproductive biology exist and that there is 
the need for regional sampling and detailed examina¬ 
tion of the reproductive state of spiny dogfish for com¬ 
parative purposes. 
Because of the significance of female reproduction 
for the sustainability of the WNA spiny dogfish fishery 
and because of new data on the plasticity and latitu¬ 
dinal variations in other elasmobranchs (Driggers and 
Hoffmayer, 2009; Taylor et al., 2016), more informa¬ 
tion specific to this stock in each region is required to 
determine whether latitudinal plasticity exists and to 
ensure accurate assessments and reliable projections 
that lead to more sustainable management practices. 
An intensive sampling regimen was initiated to obtain 
detailed life history data as part of the Cooperative 
Research Program of the National Marine Fisheries 
Service’s (NMFS). We report on one portion of this 
study, specifically, the gestation period and pupping 
seasonality of mature female spiny dogfish off SNE 
between Massachusetts and Rhode Island and in the 
mid-Atlantic off the coast of New Jersey. We address a 
lack of adequate data on reproductive characteristics 
in this region and revisit fecundity at maternal length 
to evaluate any density-dependent effects that may 
have occurred as the female spawning stock biomass 
was rebuilding. 
Materials and methods 
An attempt was made to collect a minimum of 30 ma¬ 
ture female spiny dogfish greater than or equal to 50% 
maturity (which was estimated at 75 cm in stretched 
total length, STL] [66.1 cm fork length, FL] [Bubley, 
2010]), per month for 2 years from July 2013 through 
July 2015. Female spiny dogfish were requisitioned 
from commercial fishing vessels fishing primarily off 
SNE between Massachusetts and Rhode Island but 
some sampling occurred off the coast of New Jersey 
through the NMFS Cooperative Research Program. 
Sampling location and date were noted and the sam¬ 
ples were frozen. If sample length was <75 cm STL and 
the sample was mature it was included in the study. 
Fork, total, and stretched total lengths were mea¬ 
sured over the body (FL: from the tip of the snout to 
the fork in the tail; TL: from the tip of the snout to 
a point on the horizontal axis intersecting a perpen¬ 
dicular line extending downward from the tip of the 
upper caudal lobe to form a right angle; and STL: from 
5 Sulikowski, J., B. Galuardi, W. Bubley, W. Driggers III, E. 
Hoffmayer, A. Cicia, A. Carlson, and P. Tsang. 2010. Dis¬ 
missing dogma? What do we really know about the spiny 
dogfish, Squalus acanthias, population in the U.S. western 
north Atlantic Ocean. ICES CM 2010/E: 16, 8 p. [Available 
from website.] 
