98 
Fishery Bulletin 115(1) 
Our results indicate that adult female spiny dogfish 
may select warmer inshore habitats not for foraging 
but to reduce gestation time of embryos, as has been 
reported to occur in the round stingray (Urobatis hal- 
leri) and may be common in other elasmobranchs (Jirik 
and Lowe, 2012). Further research should be focused 
on understanding the influence of primary productivity 
on habitat selection in spiny dogflsh, by sex, to evalu- 
ate the link with gestation and the possible link with 
foraging success (Dell’Apa et ah, 2015). 
From a management perspective, the results of this 
study indicate a higher probability of catching spiny 
dogfish at higher latitudes, mainly on the Georges 
Bank shelf area, where the stock of this species is com- 
monly reported to aggregate between spring and fall 
(Rulifson, 2010). Results also indicate that there is a 
higher probability of adult male aggregations inshore 
in coastal waters during the fall. Additionally, a lower 
abundance of adult females was predicted to be found 
in the fall in these same waters. Combined, these re- 
sults indicate that the Georges Bank shelf area may be 
explored for the development of a male-only directed 
fishery in the fall. However, further studies are needed 
to confirm this hypothesis, studies that possibly could 
combine data analyses of both fishery-independent 
(e.g., NEFSC surveys) and fishery-dependent surveys 
in the New England region. 
Additionally, the results from this study indicate that 
a potential male-only directed fishery, mainly in the 
Georges Bank shelf area, could be limited to fishing in 
the afternoon, when fewer aggregations of adult females 
are predicted to be associated with coastal waters, and 
in the fall, when higher numbers of adult females are 
predicted to select deeper waters. Sagarese et al. (2014a) 
noted that during the fall, adult females may move into 
offshore waters as a strategy to avoid encountering adult 
males — a suggestion also made by other authors (Veris- 
simo et al., 2011; Dell’Apa et al., 2014). Future research 
should be undertaken to compare and integrate the spa- 
tiotemporal habitat distribution of spiny dogfish, by sex, 
found in this study with that of fishery-independent 
surveys, such as the surveys that the NEFSC has con- 
ducted in offshore waters and for a longer period of 
time, and with that of fishery-dependent surveys, which 
provide less standardized but more direct information 
on the influence of fishery exploitation of this species be- 
tween New England and North Carolina. Because tem- 
perature and depth are key environmental variables for 
prediction of the abundance in both sexes, more studies 
are also needed to understand the influence of climate 
change in the spatial distribution of spiny dogfish along 
the northwest Atlantic coast and continental shelf (Nye 
et al., 2009; Sagarese et al., 2014a). 
Acknowledgments 
We thank all the people who have worked on the 
FA^ Darana R at the Virginia Institute of Marine Sci- 
ence in Gloucester Point, Virginia, from crew members 
to those people who volunteered to help collect data 
and samples during the surveys. We are grateful to S. 
Sagarese and to 3 anonymous reviewers for their valu- * 
able inputs and comments that helped to improve the 
quality of this manuscript. 
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