Habitat selection and 3D space use partitioning of resident juvenile hawksbill sea turtles in a small Caribbean bay

Abstract

Understanding how aquatic animals select and partition resources provides relevant information about community dynamics that can be used to help manage conservation efforts. The critically endangered hawksbill sea turtle (Eretmochelys imbricata) spends an extended part of its juvenile development in coastal waters. A strong proclivity to remain resident in small areas, often in high density, raises questions about how juveniles partition resources including selection of habitat and spatial overlap among conspecifics. Using between 36 and 41 acoustic receivers in the 1.5 km2 study site, this study quantified day-and-night habitat selection, as well as 2D and 3D space use of 23 juvenile hawksbills within two adjacent Caribbean foraging grounds—Brewers Bay and Hawksbill Cove, St. Thomas, US Virgin Islands—between 2015 and 2018. We found that coral reef, rock, and the artificial dolosse forming an airport runway, were the most strongly selected habitats based on resource selection indices. Individual activity spaces in 2D and 3D were both larger during the day compared to night, although the same parts of the bay were used by each individual during both periods. The 3D approach also showed deeper space use during the day. Weekly comparisons of activity space between individuals showed limited overlap (mean 95% UD overlap; day: 0.15 (2D) and 0.07 (3D), night: 0.11 (2D) and 0.03 (3D)), suggesting some degree of resource partitioning or territoriality. Results from this study provide relevant space use information for resource management of juvenile hawksbills, in which many populations are facing habitat degradation and population declines.

Comparing acoustic and satellite telemetry: an analysis quantifying the space use of Chelonia mydas in Bimini, Bahamas

“…Although the array design and species’ behaviour of our target population are highly specific, the results from this study suggest that acoustic telemetry may be more appropriate for answering fine-scale ecological questions, such as those related to diel and tidal movement patterns, habitat use within highly heterogeneous benthic substrate, or use of discrete habitats for specific behaviours (e.g. resting spots) [ 43 , 61 , 108 – 110 ]. Acoustic telemetry may also be better suited for studies in constrained water bodies (e.g.…”

Exploring Multifunctional Markers of Biological Age in Farmed Gilthead Sea Bream (<em>Sparus aurata</em>). A Transcriptomic and Epigenetic Interplay for an Improved Fish Welfare Assessment Approach

“…When results from S+3 vs S+1 fish were compared and the identified discriminant DE transcripts known to be located in coding areas (668) were matched with those containing DM regions of discriminant value (14,366), only 172 were overlapping (Figure 3A). The over-representation analysis of the list of discriminant DE coding transcripts (668) discerned 442 enriched functions (Gene ontology -Biological process, GO-BP, unique terms; Table S2A).…”

“…2 [12,13], though each target tissue would provide different information on the welfare state and particularly on the timing of the stress response. Likewise, behavioural monitoring is often difficult in the aquatic environment [14,15], but the use of miniaturized data-loggers externally attached to the operculum of sentinel fish represent a practical solution for a continuous and accurate individual tracking of swimming activity and breathing rates in tank-based rearing systems [16].…”

A Systematic Review of Acoustic Telemetry as a Tool to Gain Insights Into Marine Turtle Ecology and Aid Their Conservation

“…It has been suggested that vertical habitat partitioning may occur, which has implications for individuals' access to food and shelter (Makowski et al, 2006;Blumenthal et al, 2009b;Hart et al, 2012;Carrión-Cortez et al, 2013). Further exploration of how depth mediates space use is necessary, but the cost of additional sensors may be a limitation to incorporating this data into acoustic telemetry studies (Matley et al, 2021a).…”

“…However, since signals transverse through water easily, acoustic telemetry allows for near-continuous monitoring of marine turtles, who spend 91-97% of their time submerged (Renaud et al, 1995;Schmid et al, 2002), As a result, acoustic telemetry provides higher numbers of detections, improved resolution, and lower positional errors than other tracking techniques, such as satellite telemetry, which only transmits location data when turtles surface (Hazel, 2009;McClellan and Read, 2009;Hart et al, 2012;Whoriskey and Hindell, 2016). Therefore, when within the range of receivers, acoustic telemetry presents an opportunity for effectively collecting spatial information for marine turtles (Matley et al, 2021a;Pillans et al, 2021).…”