88°W 
Figure 1 
Map of the locations of 5 artificial reef sites where a Vemco Positioning System (VPS) 
was deployed (black circles) and of 21 surrounding reef sites where an acoustic receiver 
was deployed (gray circles) within the Hugh Swingle General Permit Area (black square 
outline in inset) in the northern Gulf of Mexico. Gray triggerfish (Balistes capriscus) 
were tagged and released at the VPS sites from 23 January 2013 through 16 June 2017. 
Fish movements were monitored at all sites until 5 September 2017. The dotted lines 
Fishery Bulletin 120(2) 
indicate 5-m depth contours. 
Fish tagging and cage-release method 
We tagged and released adult gray triggerfish (sample size 
[n]=56) on artificial reef sites from 23 January 2013 through 
16 June 2017 and monitored movements until 5 September 
2017. Prior to tagging, we measured dissolved oxygen con- 
centration and temperature throughout the water column 
using a multiparameter water-quality sonde (YSI Model 
6920, YSI Inc., Yellow Springs, OH). Fish were tagged and 
released if dissolved oxygen levels were >2.5 mg/L. If water 
temperatures at the surface exceeded 27°C, ice was added 
to the holding tanks during sedation and recovery to reduce 
stress from high temperatures. 
Gray triggerfish were captured with hook-and-line 
gear baited with squid (Loligo spp. or Lolliguncula spp.) 
at 5 VPS sites (Fig. 1). On the research vessel, adult fish 
2250 mm FL (Kelly-Stormer et al., 2017) were anesthe- 
tized in 70-L containers with 150 mg tricaine methane- 
sulfonate (MS-222)/L seawater (Munday and Wilson, 
1997; Cho and Heath, 2000) for 80 s to level 4 of sedation 
(loss of equilibrium, fin movement stopped; Summerfelt 
and Smith, 1990). After anesthesia, fish were weighed 
(to the nearest 0.1 kg) and measured to the nearest 
millimeter in total length, FL, and standard length. An 
acoustic transmitter (V13-1L or V13P-1L) was surgi- 
cally implanted within the peritoneal cavity through a 
vertical incision of 1-2 cm on the ventral left side. The 
incision was then closed with 2—3 discontinuous, dissolv- 
able sutures (chromic gut surgical sutures, Ethicon Inc., 
Raritan, NJ). Povidone-iodine (Betadine, Avrio Health 
L.P., Stamford, CT) was applied over the incision to 
reduce the risk of infection. Fish were also tagged with 
an external anchor tag (FM-95W, Floy Tag & Manuf. Inc., 
Seattle, WA) inserted 1-2 cm posterior to the incision, 
with a unique identification number, contact information, 
and reward notice for later identification by fishermen or 
scuba divers (Herbig and Szedlmayer, 2016). 
After tagging, fish were transferred to a 185-L recovery 
tank with aerated seawater. During the recovery period, fish 
were monitored for increased opercular pumping, control 
