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Fishery Bulletin 116(3-4) 
72W 71W 70W 72W 71W 70W 
Figure 7 
Occurrence (blue dots) of age-0 black sea bass (Centropristis striata ) in trawl sur¬ 
veys conducted during autumn by the Massachusetts Division of Marine Fisheries 
and the Northeast Fisheries Science Center (NEFSC) at the northern distribu¬ 
tional limit of this species off southeastern Massachusetts, from 1978 to 2016. 
See Supplementary Material for areal extent of the NEFSC sampling coverage 
(~36-44°N). Numbers of age-0 fish (n) are provided. Black lines indicate the 50- 
and 100-m isobaths. A red X indicates the position of the sea-surface temperature 
buoy referred to in Figure 8. 
spawning is not favored in southern New England wa¬ 
ters because the resulting age-0 fish would not grow to 
a sufficient size or store sufficient energy to avoid over¬ 
wintering mortality (Munch et ah, 2003; Bell, 2012). 
The timing and length of the spawning season may 
itself be subject to change, if warming continues, as 
suggested by supplemental data in Walsh et al. (2015); 
therefore further monitoring is warranted. 
Our estimates of hatching dates are both accurate 
and precise. Daily microincrement formation in black 
sea bass otoliths has been validated by Hales and Able 
(1995) using OTC marked fish released and recaptured 
in the wild. Our effort confirms the age validation step 
of Hales and Able (1995) and shows the level of preci¬ 
sion in our specific estimates. Nonetheless, we have as¬ 
sumed that the first microincrement corresponds with 
hatching specifically, but it could be laid down earlier 
during embryogenesis. In general, we assume a negli¬ 
gible difference between the times of deposition of the 
first growth ring, hatching, and spawning. A review of 
the literature suggests that our estimates of hatching 
dates may differ from spawning dates by as much as a 
week. Egg incubation is reported to range from 38 h at 
23°C to 75-120 h at 15-16°C (Wilson, 1889; Hoff 5 ; Ken¬ 
dall, 1972). The difference between spawning, hatch¬ 
ing, and the first microincrement may be more than 5 
d in Buzzards Bay and Nantucket Sound with May bot¬ 
tom temperatures of 10-12°C (King et al. 2 ), but would 
be shorter later, June or July, as temperature increas¬ 
es and survival of eggs would improve (optimized at 
22-25°C; Watanabe et ah, 2003). These potential ad¬ 
justments would push the calculation of spawning sea¬ 
sonality earlier, especially when sea temperatures are 
5 Hoff, F. H. 1970. Artificial spawning of the black sea bass 
Centropristis striata melanus (Ginsberg), aided by chorionic 
gonadotrophic hormones. Fla. Dept. Nat. Resour. Mar. Res. 
Lab. Spec. Sci. Rep. 25, 17 p. 
