Graduate Research, Dept. of Environmental Conservation September 2015 – May 2018
University of Massachusetts Amherst – Amherst, MA
University of Massachusetts Amherst – Amherst, MA
Yellowtail snapper Ocyurus chrysurus
Between 2015 and 2016, eight yellowtail snapper were tagged with acoustic transmitters in Buck Island Reef National Monument (BIRNM), a marine protected area in the U.S. Virgin Islands, managed by the National Park Service. Individuals were tracked within an array of 78 passive acoustic receivers, with an additional 25 nested in a VEMCO Positioning System (VPS) to the west of Buck Island adjacent to the shelf break. Broad-scale data were analyzed using network analysis and showed all individuals had core use receivers (areas of high connectivity) near capture locations and near the shelf break (black halos around grey circles are core use receivers; Figure 1).
Fine-scale movement analyses with the VPS positioning data showed distinct space use patterns between fish, reduced movement at night, and no significant study population habitat selectivity. Overall, it was important to quantify differences in the ecological inferences made between broad- and fine-scale telemetry data. Broad-scale telemetry is more suited for identifying movement corridors and should be used in a strategic manner for understanding MPA effectiveness. Fine-scale telemetry data allowed us to capture individual movement patterns, space-use, and habitat selection, and should be used when research seeks to answer those questions. |
Figure 1. An example of a yellowtail snapper (Tag 19664) spatial network graph in BIRNM. Grey circles are receivers and ones with grey halos are receivers Tag 19664 visited. Grey circles with black halos are core use receivers. Larger halos indicate more use, and thicker lines connecting circles shows higher numbers of connections (or inferred movement) between them.
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Horse-eye jack Caranx latus
Due to opportunistic tagging of fish in BIRNM, movements of seven horse-eye jack were tracked with identical methods to the yellowtail snapper research. Little is known about horse-eye jack, despite their prevalence across their range from New Jersey, USA to Brazil. Network analysis suggested this species is highly mobile and frequently leaves the boundaries of BIRNM, but it largely resident to the general area. Species that are highly mobile present challenges to static spatial management and thus is an important consideration to how these areas are designed to meet the needs of multiple species of interest and economic concern.
Great barracuda Sphyraena barracuda
Fine-scale VPS data supported previous research in BIRNM (Becker et al. 2016) that showed barracuda are highly territorial and patrol their core use territories daily. Fish displayed both resident and transitory behaviors, and these larger exploratory movements away from home territories coincided with a full moon event (unpublished data). Further, there is evidence that barracuda exhibit diel variation in location of activity spaces (Becker, Finn, Novak et al. 2019).