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Fishery Bulletin 111(4) 
Figure 2 
Spatial extent of the area used in the large-scale analysis of shark distribution in the northern Gulf of Mexico dur- 
ing 2006-09. (A) Seventeen National Marine Fisheries Service statistical zones (4-21 east to west, excluding zone 
12), which spanned depths from 1 to -250 m, where the bottom-longline sets were conducted by the NOAA Southeast 
Fisheries Science Center Mississippi Laboratories during the months of August and September. (B) Sampling locations 
for the large-scale bottom-longline data for 2006-09 are indicated by filled circles; trawl data for 2007-09 from the 
Southeast Area Monitoring and Assessment Program database (http://seamap.gsmfc.orgl are indicated by open circles. 
survey design that ensured equal effort across blocks 
1-8 and the range of depths sampled (Fig. 1A). At each 
station, a single bottom-longline was set and soaked 
for 1 h. The main line consisted of 1.85 km (1 nmi) 
of 4-mm monofilament (545-kg test) that was set with 
100 gangions. Gangions consisted of a longline snap 
and a 15/0 circle hook baited with Atlantic Mackerel 
( Scomber scombrus). Each gangion was made of 3.66 m 
of 3-mm monofilament (320-kg test). 
Sharks that could be boated safely were removed 
from the main line, unhooked, and identified to species 
following Castro (2011). For each individual, sex, length 
(precaudal, fork, natural, and stretch total in centime- 
ters), weight (in kilograms), and maturity stage (when 
possible) were recorded. All length measurements 
originated at the tip of the rostrum and terminated at 
the origin of the precaudal pit, the noticeable fork in 
the tail, the upper lobe of the caudal fin in a natu- 
ral position, and the upper lobe of the caudal fin in 
a stretched position for precaudal, fork, natural, and 
stretch total lengths, respectively. Maturity in males 
was assessed according to Clark and von Schmidt 
(1965). Sharks were tagged either on the anterior dor- 
sal fin with a plastic Rototag 1 (Dalton ID, Henley-on- 
Thames, UK) or just below the first dorsal fin with a 
metal dart tag. Which tag type was used depended both 
1 Mention of tradenames or commercial companies is for iden- 
tification purposes only and does not imply endorsement by 
the National Marine Fisheries Service, NOAA. 
