Little is known about the movement patterns of gray triggerfish, Balistes capriscus Gmelin, in the northern Gulf of Mexico. To examine fine‐scale movements, gray triggerfish (n = 17) were tagged with transmitters and tracked with the VR2W Positioning System from 17 October 2012 to 9 December 2013. Most (76%) tagged fish survived and were tracked for 1–57 weeks. Tagged fish showed significantly larger home ranges and core areas in autumn than winter–spring and during day than night. Seasonal movement patterns were positively correlated with water temperature. Gray triggerfish stayed close to the reef (mean ± SD distance = 35.9 ± 28.4 m) and showed high site fidelity (64%) and high residency (>57 weeks). These patterns emphasise the importance of structured habitat for this species and suggest that artificial reef building in the northern Gulf of Mexico has enhanced this population.

The Western Dry Rocks (WDR) area off Key West, Florida, is an open fishing area that contains a multispecies fish spawning aggregation site, but grouper spawning there has yet to be confirmed. The movements of 18 adult and subadult grouper at WDR were tracked using acoustic telemetry to determine how this area is used by grouper species and whether it contains a grouper spawning aggregation site. Tagged fish consisted of 10 Black Grouper Mycteroperca bonaci, 5 Nassau Grouper Epinephelus striatus, 2 Gag M. microlepis, and 1 Yellowfin Grouper M. venenosa. Overall, tagged grouper were more likely to be present in the WDR array during winter spawning months, with species-specific seasonal differences. Our results indicated that grouper presence increased during spawning months, although some adults and subadults were present year-round. Grouper made more movements per day during nonspawning months compared to spawning months, although the north side of WDR was the most heavily used area, regardless of the time of year. Additionally, spatial graphs of grouper movement suggested that different grouper species utilized different areas of WDR. Increased presence of grouper during spawning months suggests that the WDR area may contain a grouper spawning aggregation site, which would mean that fish species aggregate to spawn at this location year-round. The success of the Florida Keys fisheries critically depends on the protection of multispecies spawning aggregations like that potentially contained at WDR.

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Background With the increase in telemetry studies over the past decade, improving understanding of how different tagging methods influence the probability of presence in a receiver array is important in maximizing the resulting data. Disappearance from the array may be due to mortality from surgery complications, tag loss, predation, or emigration. Internally tagging fish on a boat can cause barotrauma injuries, increased stress from prolonged handling times, or predation after fish have been released back into the water. Conducting in situ internal acoustic tagging at depth of capture removes barotrauma stresses and simplifies the release method, which may improve fish survival and decrease risk of disappearance from the array. In this study, we used 8 years of acoustic tagging data to determine if the tagging method (in situ versus on the boat) influenced the likelihood of a fish being detected 4 and 6 days after the tagging event. Results At 6 days after tagging, Kaplan–Meier survival curves revealed that the probability of presence for fish tagged on the boat was 66% compared to 90% for fish tagged in situ. Tagging method was the only variable to significantly affect probability of presence based on Cox proportional hazards models, with fish tagged in situ ~ 75% less likely to disappear from the array compared to fish tagged on the boat at both 4 and 6 days after tagging. Examining tagging methods separately, handling time only marginally influenced probability of presence of boat-tagged fish and no variables had a significant effect on probability of presence of in situ tagged fish. Conclusions In this study, tagging method was the only variable to significantly affect the probability of presence for internally tagged fish. Other factors had little to no influence, but correlation of variables limited what factors could be included in the models. Implanting internal acoustic tags in situ is not a practical method for every species and for every environment, but given the increased probability of presence demonstrated here, we strongly suggest it be considered where applicable.

Herbivorous reef fishes control algal growth and are critical for maintaining reef health. Grazing effects vary due to community composition, so a diverse herbivore community is important for preventing phase shifts from coral to algal-dominated reefs. However, herbivore communities and grazing effects vary spatially, resulting in non-uniform distribution of algal mitigation across the seascape. Therefore, understanding how habitat influences herbivore communities is essential for predicting the spatial distribution of these species’ ecological services. This study used underwater visual surveys (n = 5455) to examine how habitat influences spatial patterns of herbivorous fish densities and species richness in the Florida Keys and Dry Tortugas, Florida. Herbivorous fishes were ubiquitous, and communities were dominated by small herbivores such as damselfishes (Pomacentridae), gobies (Gobiidae), surgeonfishes (Acanthuridae), and small– to medium–bodied parrotfishes (subfamily Scarinae). A suite of factors influenced herbivorous fish communities but boosted regression tree results showed that habitat relief, depth, and spatial location within the Florida Keys and Dry Tortugas were the most important factors. In general, herbivore occurrence, density, and species richness increased as percent of low relief hardbottom habitat (<0.2 m high) decreased. In addition, density and occurrence of herbivores generally increased at shallower depths. Spatial location influenced the density of herbivores with potential hotspots predominantly located in the Upper Keys and the Dry Tortugas Bank. These data provide a valuable understanding of the spatial distribution of herbivorous reef fishes, and aid management decisions regarding the protection and sustainability of herbivore resources and the ecosystems that rely on them.