DOI: 10.5061/dryad.4j0zpc89t
title: Data from: Reverse diel vertical movements of oceanic manta rays off the northern coast of Peru and implications for conservation

description: An understanding of the vertical movements of elasmobranchs across their
 range is crucial to defining critical habitat use, its overlap with
 anthropogenic activities, and subsequently managing such interactions. In
 this study, satellite telemetry was used to investigate the vertical
 habitat use of three oceanic manta rays (Mobula birostris) tagged on the
 northern coast of Peru. All three oceanic mantas exhibited patterns of
 reverse diel vertical migration, where vertical movements were
 significantly deeper at night than the day, as well as an overall
 preference for surface habitats (&lt; 2 m). High-resolution archival
 data (3-5 s) from two recovered tags revealed fine-scale behaviours, where
 individuals predominately remained in coastal surface waters throughout
 the day and oscillated up and down through a highly stratified water
 column at night. Our results suggest that coastal vertical movements were
 motivated by a combined foraging and thermal recovery strategy, whereby
 oceanic mantas dived to forage on vertically migrating zooplankton at
 night and returned to surface waters to rewarm between dives, indicating
 that the coast of northern Peru may be a foraging habitat for these
 animals. High use of surface waters here, however, may put oceanic mantas
 at high risk from several anthropogenic impacts such as entanglement with
 fishing gear and vessel strikes. Increased sample size and the use of
 other techniques, such as animal-borne cameras and tri-axial sensors, are
 required to validate our foraging and thermal recovery hypothesis and
 confirm this region as a foraging habitat for oceanic mantas.
description: Five
 pop-up satellite archival (PSAT) tags (MiniPAT 348F-00; Wildlife Computers
 Inc., WA, USA) were deployed on oceanic manta rays (<i>Mobula
 birostris</i>) in May (n = 1) and July (n = 4) 2018 off the Tumbes
 region of the northern coast of Peru (Fig. 1). Mantas were visually
 located at the surface by boat-based searches carried out together with
 local fishermen, and externally tagged by free-divers. All tags were
 leadered according to Wilson et al. (2015). Briefly, leaders consisted of
 a ~15−17 cm length of 180 kg monofilament (Moimoi, X Hard) covered with
 one layer of Aramide and shrink wrap, and were attached to the manta via a
 custom-built titanium dart. Mantas were tagged by a swimmer with a pole in
 hand, and tags were placed into the dorsal musculature, off the midline of
 the posterior dorsal surface of each manta ray. PSATs were programmed to
 sample ambient light levels, ambient temperatures, and pressure at 3-5
 second intervals and to detach after 90 (May) or 180 (July) days (Table
 1). Depth and temperature time-series were transmitted at five-minute
 intervals, and recovery of two tags through collaboration with local
 community members allowed for the whole archival datasets to be
 downloaded.
description: MR1: 5218001 MR2: 5218005
 MR3: 5218007 Tags from MR1 and MR3 were
 physically recovered, allowing download of the full data
 archives. Data were extracted from the raw tag data
 using the Wildlife Computers Data Analysis Program 3.0 (available at https://wildlifecomputers.com/support/downloads/). Please refer to the PDF at https://static.wildlifecomputers.com/Spreadsheet-File-Descriptions-1.pdf for more detail on each file.