10.5061/DRYAD.4J0ZPC89T
Andrzejaczek, Samantha
0000-0002-9929-7312
Stanford University
Schallert, Robert
Stanford University
Forsberg, Kerstin
Planeta Oceano
Arnoldi, Natalie
Stanford University
Cabanillas, Mariano
Federal University of Rio Grande do Sul
Purizaca, Wilmer
Planeta Oceano
Block, Barbara
Stanford University
Data from: Reverse diel vertical movements of oceanic manta rays off the
northern coast of Peru and implications for conservation
Dryad
dataset
2021
2021-02-22T00:00:00Z
2021-02-22T00:00:00Z
en
194186719 bytes
8
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
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 (< 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.
Five pop-up satellite archival (PSAT) tags (MiniPAT 348F-00; Wildlife
Computers Inc., WA, USA) were deployed on oceanic manta rays (Mobula
birostris) 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.
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.