Manta Project Fiji Impact Report 2023

Feeding Sites
Zooplankton Diversity
Non-Feeding Site
Acetate Protozoa, 4%
Chaetognaths, 5%
Chaetognaths, 4%
Chaetognaths, 4%
Chaetognaths, 2%
Copepod, 75%
Lucifer sp., 8%
Copepod, 88%
Copepod, 81%
Lucifer sp., 4%
Copepod, 94%
Sagitella, 5%
Lucifer sp., 11%
Lucifer sp., 15%
Copepod, 100%
Assessing the foraging
habitat of oceanic
manta rays in laucala
bay, FIji
Suva
Viti Levu
Laucala Bay
Project Overview
Oceanic Manta Ray
(Mobula birostris)
This research project was led and designed by University of the South Pacific
undergraduate students Karalo Drekenavere and Devavrat Bishwa and focuses
on Laucala Bay, Fiji, where recurrent sightings of M.birostris raise questions
about their ecological significance and the potential impacts of anthropogenic
activities.
The investigation examined water quality parameters, fecal coliform bacteria
concentration, microplastics, and zooplankton composition within the bay at
four foraging sites and one non-foraging site. During the study a drone was used
for real-time identification of foraging manta rays and to give the boat direction
to the specific site. Once at the specified site with the manta ray foraging water
samples and parameters were taken and a plankton net deployed.
Copepods were
present at all
sampled sites,
both feeding and
non-feeding
Lucifer sp., a species of
prawn was a surprise
finding at every feeding
site. Lucifer sp. were not
present at the
non-feeding site
Chateognaths, also
known as arrow
worms were present
at all feeding sites
but absent from the
non-feeding site
Fragments, 63%
Fibres, 32%
Line, 5%
Only copepods were
present at the non-feeding
site, displaying clear
differences between the
feeding and non-feeding
site
microplastic Distribution
Feeding Sites
Microplastic fragments accounted for
63% of all microplastics collected at
feeding sites, with fibres making up
32% and line only 5%.
Water Quality Parameters:
Lucifer sp.
Key Partner
- Temperature, Dissolved Oxygen and
Salinity
- Turbidity
- Fecal Coliform Bacteria
Fragments, 13%
Fibres, 87%
Non-feeding Site
Microplastic fibres accounted for the
majority of all microplastics collected
at non-feeding sites with 87% and
fragments only accounting for 13%.
- Microplastic Composition
The University of
the South Pacific
The University of the South Pacific marine science
campus sits on the foreshore of Laucala Bay. This
has created a great opportunity for Manta Project
Fiji and the Univeristy to work together collecting
data in this critical ecosystem.
- Zooplankton Analysis and Composition
Karalo Drekenavere (right) and Devavrat Bishwa
(left) collect water samples at foraging sites in
Laucala Bay, Suva
Laucala Bay, Suva
Feeding and non-feeding
sites displayed very
different compositions of
microplastics, possibly due
to the differing
oceanographic conditions
Microplastic Fragment