May et al.: Fine-scale movements of Pristispectinata 
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Figure 4 
Visualization of diel movements from pooled locations of all 20 juvenile smalltooth saw¬ 
fish (Pristis pectinata ) caught and tagged with acoustic transmitters in upper Charlotte 
Harbor (Peace and Myakka Rivers), Florida, during (A) day (0900-1659) and (B) night 
(2100-0559) from May through October 2016. The color scale denotes the number of first 
detections per hour, per receiver, for each individual. The light blue color indicates areas 
where a range of 0-100 or 0-500 detections was recorded, and the white color indicates 
areas with no detections. 
shoreline habitats, yet this study is the first to explore 
interactions with oyster reefs. Although juveniles did not 
select the restored oyster habitats more often than other 
available shallow habitats, as the reefs mature, perhaps 
juveniles will interact with them more often as habitat 
complexity increases and more potential forage species 
reside in the area (Harding and Mann, 2001). 
Throughout the mixed semidiurnal tidal regime of the 
Charlotte Harbor estuarine system, smalltooth sawfish 
were detected on the southern shoreline significantly more 
often during the first flood and first ebb tides of the day, 
regardless of height. Because these first tides typically 
occurred at night, the primary driver for the across-river 
movement was likely diel, rather than tidal. 
This study is the first to use an automated positioning 
system on a sawfish species, and results indicate that this 
technology is effective in the shallow habitats where indi¬ 
viduals in the early life history stages of this and other 
relatively large fish species reside. The array of acoustic 
receivers allowed tracking data that traditionally have 
been collected manually to be automatically recorded 24 h a 
day. On the basis of the results of this preliminary, summer- 
focused study, similar arrays will be deployed in this and 
other nursery hotspots, including on the northern shoreline 
