An emerging body of literature has demonstrated the benefits of the use of circle hooks relative to standard J-hooks in commercial and recreational fisheries. In the pelagic longline fishery for tunas (Thunnus spp.) and swordfish (Xiphias gladius Linnaeus, 1758), the use of circle hooks has resulted in greater catch rates of some target species, lower catch rates of some bycatch species, and a higher percentage of many target and bycatch species alive at the time of haulback (gear retrieval). However, a lack of agreement among results of studies conducted in different fisheries and areas, using different baits and rigging techniques, and with different styles and sizes of circle hooks has hindered the adoption of this terminal tackle as a management measure at the international level. Nevertheless, some countries have mandated the use of circle hooks in pelagic longline fisheries to protect bycatch species, and some individual fishers have incorporated circle hooks because they appear to maximize individual profit. In the recreational fishery for billfishes (family Istiophoridae), which is primarily a catch-and-release fishery in the United States, studies have demonstrated that circle hooks result in higher rates of external hooking and post-release survival than standard J-hooks. The use of circle hooks in billfish fisheries has been promoted by the sportfishing industry and is currently required by some nations; however, partnerships promoting active outreach and education with stakeholders in both commercial and recreational fisheries are critical to maximize the use and conservation benefit of this technology.

Pop‐up satellite archival tags (PSATs) were deployed on 19 sailfish Istiophorus platypterus captured in the southern Gulf of Mexico and Florida Straits between 2005 and 2007 on commercial pelagic longline gear (n = 18) and recreational rod‐and‐reel gear (n = 1). The data from three tags indicated mortality events and were excluded from subsequent analyses. All PSATs were programmed to collect pressure (depth), temperature, and light‐level data for 10 d at approximately 90‐s intervals. These transmitted point data subsequently allowed the reconstruction of vertical movement patterns. The remaining 16 PSAT data sets indicate that sailfish are primarily associated with the upper surface waters within the top 20 m (75.7% of total time during the day versus 46.7% at night) but undertake numerous short‐duration vertical movements below the local mixed layer to depths of 50–150 m, presumably to feed. Analyses of 2,279 individual vertical movements among all 16 tagged sailfish indicated two distinct types (short‐duration “V” and longer‐duration “U” movements) similar to those reported for white marlin Kajikia albida. Sailfish also exhibited movement type differences between diel periods (having higher proportions of V movements in daytime), suggesting directed foraging at depth. Although short‐duration movement to depths by these tagged fish contribute a small percentage of the total time at depth, these depths overlap with the monitored shallow‐set pelagic longline gear depths actively targeting swordfish by the vessel in the local fishery. These results suggest that time‐at‐depth histograms alone may be insufficient to capture feeding motivations at depth and, therefore, true interaction potentials between individual sailfish and pelagic longline gear. Received August 14, 2010; accepted April 24, 2011

Artificial reefs may enhance the biological production of reef-associated flora and fauna, but their trophic structure relative to that of natural reefs remains understudied. We assessed trophic relationships by 1) comparing reef fish communities and 2) comparing δ13C and δ15N in 43 fish species from both artificial reef sites and adjacent natural reef tracts in Broward County, Florida. We tested the effect of sampling location (artificial, first, and second reef), general feeding strategy (herbivore, omnivore, invertivore, and carnivore), phylogeny, and standard length on δ13C and δ15N. The reef fish communities of the artificial and natural reef tracts were significantly different; the artificial sites also exhibited more variability. For all samples, δ13C and δ15N ranged from -19.5 to -13.1‰ and 6.7–13.3‰, respectively. Significant effects were detected for both general feeding strategy and phylogeny. Significant differences were also seen in δ13C and δ15N profiles between artificial and natural reefs; however, these changes were primarily driven by differences in fish community structure, rather than by changes in the feeding strategy or trophic relationships of individual fish taxa. The trophic guild invertivore was the only group of fish to demonstrate significant isotopic differences between both reef tracts (inner and outer) and reef types (artificial and natural). The artificial reef may act more as a foraging corridor between the natural first and second reef tracts for omnivores and carnivores. If the function of artificial reefs is to provide additional foraging habitat for fishes, then perhaps more time is needed for the trophically important, infaunal invertebrate community to develop similarly to the natural reef environment.