Manta Project Fiji Impact Report 2023

2023
2022
Sighting Distribution
Manta sightings have now been recorded from March
through to December in Laucala Bay. During the 2023
survey season, peaks in sightings were recorded in
May, July and September. With only just under two
years of consistent data collection we are looking
forward to build upon survey efforts for the 2024
season.
It is hypothesised that large amounts of fresh water
being deposited into the bay by the nearby Rewa river
cause dense zooplankton clouds to form, which the
manta rays gather to forage on.
Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Laucala Bay,
Suva
Suva
Conservation
International Fiji
Viti Levu
Laucala Bay
Key Partners
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.
Conservation International Fiji and Manta Project
Fiji have collaborated on deploying technical
research equipment to better understand these
endangered rays.
Reef Manta Ray
(Mobula alfredi)
Oceanic Manta Ray
(Mobula birostris)
Project Overview
Laucala Bay sits just off of Fiji’s capital city, Suva. Laucala bay is a relatively flat
costal lagoon enclosed by a barrier reef to the South, by Suva city to the west
and the delta of Fiji’s largets river, the Rewa, in the east. Besides being adjacent
to the Rewa delta, several rivers feed into the bay shedding large amounts of
fresh water into the bay throughout the year.
After an intial oceanic manta sighting in 2018, followed by some sporadic
sightings throughout 2020, concerted manta surveys began in April 2022 to
better undertsand mobulid ray use of the site. Data is collected primarily through
drone surveys around the bay due to the size of the bay and the turbid nature of
the water.
Both species of manta ray are found in the bay, this means the bay is the only site
you can see the endangered oceanic manta ray but also one of a few sites
globally where reef manta rays and oceanic manta rays can be found foraging
together.
Drone
Surveys
193
Manta SightinGs
196
2022 2023
587
Oceanic manta sightings
Reef manta sightings
3
Drone
Surveys
583
243
Manta SightinGs
267
Oceanic manta sightings
Reef manta sightings
24
16 different manta
rays recorded
with a resighting
rate of 81%
FJ-MB-0001 was
first sighted in
late 2018 and has
been sighted 42
times since
FJ-MB-0008 is
the most sighted
manta with 61
sightings over
three years
Oceanic RESIDENTS?
FJ-MB-0001
2019 2020 2021 2022 2023 2024
2023 in review
267 manta ray sightings recorded
583 drone surveys conducted
Manta rays sighted on 46% of drone flights
8 different reef manta rays and 13 different oceanic manta rays sighted
First student-led project conducted in the bay
1 Satellite tag deployed
Individuals
FJ-MB-0020
FJ-MB-0017
FJ-MB-0016
FJ-MB-0015
FJ-MB-0014
FJ-MB-0013
FJ-MB-0012
FJ-MB-0010
FJ-MB-0009
FJ-MB-0008
FJ-MB-0007
FJ-MB-0006
FJ-MB-0005
FJ-MB-0004
FJ-MB-0002
Typically oceanic manta rays have a much lower re-sighting rate compared to reef manta rays,
hypothesised due to the difference in ecological habitat use, with oceanic manta rays
typically being associated with deeper oceanic water and a highly migratory nature.
Currently our knowledge is lacking in the homerange size of this population, we are hoping to
employ more sophisticated research methodologies in the future to better understand this
unique group of manta rays.