1. Evaluation of above- and below-ground carbon stocks of mangrove forests in
Ambaro/Ambanja and Mahajamba bays, Madagascar.
H. Andriamitantsoa, L. Ravaoarinorotsihoarana, D. Ramampiherika, T. Jones, G. Cripps
(holyheriniaina@gmail.com)
Mangrove forests play an important role in climate change mitigation thanks to their significant
capacity to sequester carbon dioxide (CO2). The purpose of this study was to estimate the total
above- and below-ground carbon stored by mangrove forests in the primary mangrove ecosystems in
Ambaro/Ambanja and Mahajamba bays, located in the North-Western of Madagascar. To estimate
above- and below-ground carbon stocks, mangroves were initially stratified based on canopy cover
(Closed-Canopy (CC) and Open-Canopy (OC)). Within mangrove strata, measurement plots were
targeted and established systematically. Based on field measurements of diameter at breast height
(DBH) and tree height in 113 plots, allometric equations were applied to estimate biomass which was
subsequently converted into carbon stocks. The CC mangroves in Ambaro/Ambanja and Mahajamba
bays were 145.33±11.08MgC.ha-1 and 214.99±35.97MgC.ha-1 respectively, while the OC mangroves
in Ambaro bay were 36.44±4.56MgC.ha-1 and 38.36±5.7MgC.ha-1 in Mahajamba bay. The variability
exhibited in these preliminary results is likely attributed to ecological differences and substantially
more widespread degradation in Ambaro/Ambanja. These results help assess the feasibility of
implementing Reducing Emission from Deforestation and forest Degradation (REDD) projects based
on mangroves, and further demonstrate their significance for CO2 sequestration and their potential
financial value to decision makers.
2. Perception of the coral reefs health state and the coral farming by the villagers
of Sarodrano (Southwestern coast of Madagascar)
FANOMEZANA Lanjaniaina Cynthia, TODINANAHARY Gildas Georges Boleslas , LAHITSIRESY MAX
Gasimandova1, TSIRESY Gaëtan, LAVITRA Thierry, EECKHAULT Igor, PASCAL Benjamin
(lanjacynthia@yahoo.fr)
In order to promote polyaquaculture in the Southwestern coast of Madagascar, the “Polyaquaculture
Research Unit” (PRU) project is undertaking a case study to check out the feasibility of the
implementation of a new form of mariculture: the coral farming. Then, the study of the perception of
the coral reefs health state and the coral farming by the villagers was carried out at Sarodrano, a
pilot village in terms of village based aquaculture. Collected data from the investigations where
analysed using Khi-2 test. Results show that more than 90% of villagers affirm that the coral reefs in
this zone are degraded and the main causes are: turn of the corals blocs, stamping of the corals, use
of destructive fishing gears and sedimentation. However, corals are still diverse and healthy in some
sites of Sarodrano’s reefs: Nosy Tafara (including Nosy Arakaivo, and two small coral reefs near Nosy
Velomitahy) and in the front of the Coral reef of Sarodrano. That situation involves the importance
and the necessity of the coral farming in this village even if it is ignored by the villagers. Indeed, less
than 30% of the people have heard about the coral farming and that only after the implementation
of the PRU project and several field missions of the PRU researchers in the village. Nevertheless, after
a brief explanation of the coral farming system, 85% of the villagers are interested by practicing the
activity even if they (72%) do not really know if it is simple or complicated. For 88% of them, a “Vezo”
people can farm corals since it is not against their culture. And finally, 85% of interviewed persons
accept to practice the coral farming, but the rest still hesitates essentially because of the ignorance
of the practice.
3. Evaluation of carbon stock in the mangrove of Ambaro Bay and Mahajamba
Bay (North of Madagascar)
HAINGONIRINA Tina Harizo (haingonirina@gmail.com)
Mangrove forest plays a very important role in the fight against climate change through the carbon
storage in whatever biomass and especially on the sediment. Several studies on soil carbon stock of
forest land have already been made in Madagascar; the study on mangrove soil is still rare. The
present study is still the second research study soil carbon stock of mangrove in Madagascar. The
lack of information on this area makes the difficulty of integrating the ecosystem in REDD. This
justifies that this study is really important in evaluating the soil carbon stock of mangroves in two
different sites: Ambaro bay and Mahajamba bay. The methodological approach is especially soil
studies. The observations direct of field are followed by soil sampling to analyze the Radio Isotope
Laboratory. For sampling, five depth levels are fixed (0-15 cm, 15-30 cm, 30-50 cm, 50-100 cm and
100-150 cm), and four strata types of mangroves are considered (open canopy, closed canopy,
degraded and tan).The results of the laboratory analysis according to the protocol of Walkley-Black
can know the carbon content of the soil and the bulk density to calculate the total carbon stock of
the soil. The study shows that the difference between the depth levels and strata considered in the
two study sites are significant. The stock of carbon varies depending on the depth and also the
following strata studied. Than the depth is deep, the higher the carbon increases. The study results at
both sites shows that the average stock of soil carbon Mangrove Ambaro bay is very high (454.20 ±
20.89 Mg / ha) compared to the stock of soil carbon Mahajamba bay (193, 60 ± 13.98 Mg / ha). An
unexpected result appeared during the fieldwork in Ambaro Bay: it is the discovery of a new species
Xylocarpus moluccensis.
4. Relative abundance of zooplankton at Nosy Tafara coral reef (Sarodrano,
South-western Region of Madagascar)
LAHITSIRESY MAX Gasimandova, FANOMEZANA Lanjaniaina Cynthia, TODINANAHARY Gildas Georges
Boleslas, TSIRESY Gaëtan, EECKHAULT Igor, LAVITRA Thierry
(mlahitsiresy@yahoo.fr)
Marine life is based on the exchange and transformation of energy which link all the organisms in a
huge system forming the food chain. In order to estimate the availability of the base of the chain, a
study of the distribution of zooplankton was carried out at Nosy Tafara coral reef (Sarodrano, Southwestern Region of Madagascar, at latitude 23°30’), from February to April 2013. In this study, four
sampling were done during the full moon and new moon using plankton net of 63µm mesh. Samples
were fixed with 3% formalin and macroplankton and microplankton are identified at the laboratory
using photonic microscope. The population of zooplankton at Nosy Tafara is dominated by nauplii
larvae, the tintinnid and copepods with the proportion of 53%, 29% and 15% of the total zooplankton
population respectively. The rest is composed by pteropoda (1%) and appendicular (2%) This
significant abundance, especially of nauplii larvae can be explained by a high abundance of
phytoplankton in this area which is a food source for zooplankton and filter-feeding organisms.
According to these results and considering that the Nosy Tafara coral reefs health state including
Arakaivo which is preserved and Nosy Velomitahy and Nosy Masaka with a potential of regeneration,
may there have any correlation between the abundance and diversity of the zooplankton and the
health state of the coral reef? An additional study of zooplankton in other degraded and nondegraded coral reefs should be done so as to allow the comparison of the results.
5. Effect of the size release of sea cucumber juveniles on their survival and
growth during the 3 first months of rearing in pens (case of Tampolove site).
Thierry LAVITRA, Gaetan TSIRESY, Richard RASOLOFONIRINA, Antoine ROUGIER & Igor EECKHAUT
(lavitra_thierry@yahoo.fr)
For sea cucumber Holothuira scabra farming, juveniles of 15g size are transferred into pens, for their
growth where high mortality is occurred during the 2 first months of rearing. This is due especially to
the predator crab Thatlamita crenata. The use of covered pen (nursery) was supposed to be the best
solution to protect those juveniles. An experiment was carried out in Tampolove (sea cucumber
farming site in the north western coast of Toliara-Madagascar) from June to September 2012 which
aimed to see the effect of the nursery and the size release of juveniles on their survival and their
growth. For this experiment, 8 nursery and 8 pens of 16m² each were constructed and 4 size classes
different of juveniles were tested: [0-5g[; [5-10g[; [10-15g[and [15-20g[. The rearing density was 3
individuals m-2. After 3 months of rearing, the results showed that the average survival rates were
83,75%+/-6,18; 88%+/-13,88; 78%+/-17,49 and 83%+/-13,63 for the H. scabra juveniles of [0-5g[; [510g[; [10-15g[ and [15-20g[ of size release respectively. Thus the size release of H. scabra juveniles
did not affect their survival (p=0,7640). Also, the use of nursery did not affect their survival rates
(p=0,226). They were 87,50%+/-11,42 and 78,88%+/-12,87 respectively for juveniles reared in
nursery and in fences. Regarding their growth, as juveniles of different sizes were released at the
beginning of the experiment, their average weights were different (p=0,0001) after 3 months of
rearing. They were 35,25g+/-4,14; 48,80g+/-3,80; 58,32g+/-5,72 and 62,99g+/-4,02 respectively for
juveniles of size release of [0-5g[ ; [5-10g[ ; [10-15g[and [15-20g[ In the other hand, no significant
difference was observed for the weight of juveniles reared in nursery (51,66g+/-13,39) and of those
reared in pens (51,01+/-10,59) (p=0,794). Sea cucumber juveniles of 5g could be released in pens and
the use a nursery is not necessary in Tampolove.
6. Abundance and distribution of Thallamita crenata crabs (redoubtable
predator of sea cucumber Holothuria scabra juveniles) in Sarodrano and
Tampolove (two main sea cucumber farming villages in SouthWestern coast of
Madagascar) and identification of the best trap system and bait to catch them.
Thierry LAVITRA1, Gaetan TSIRESY, Richard RASOLOFONIRINA, Antoine ROUGIER2 & Igor EECKHAUT
(lavitra_thierry@yahoo.fr)
The sea cucumber farming is well developed in two main fishermen villages (Sarodrano and
Tampolove) in the Southwestern coast of Madagascar. The problem remains the high mortality rate
(60-70%) which occurred during the two first months of rearing. This is due to Thallamita crenata
crabs, the main predators of Holothuria scabra juveniles. This study aimed to (i) see the abundance
and distribution of those crabs in Sarodrano and Tampolove sites and (ii) identify the best trap
system and bait to catch them. For abundance and distribution study, the transect method of 50m
length and 2m width (100m² surfaces) was used. Within each study site, 5 transects were placed in
each biotope (littoral, seagrass bed and micro-atolls) and the number of crabs observed in 100 m²
were counted. For the trap system, 3 different types were tested: trap without bucket, trap with
bucket and trap made only with bucket buried in the ground. For each trap, 3 baits were used
(crushed fish, gastropod and crustacean hermit crab). The result showed that the T. crenata crab is
more abundant in Sarodrano (0,31 crabs.m-2+/-0,37) than in Tampolove (0,028 crabs.m-2+/-0,021)
and that for all biotopes studied (p=0,002). Also this crab occurred more in the sea grass bed
compared to the other biotopes (p=0,0001). Regarding the trap system, the one with bucket is more
efficient compared to those without bucket and made with a bucket buried in the ground (P=0,0001)
with average number of captured crabs 1,35; 0,56 and 0,13 per day respectively. Also the number of
the captured crab depended on the bait used (p=0,0001) where the crushed fish attract more crabs
than the crashed crabs or hermit crab . Many crabs are found in Sarodrano village and the use of trap
made with bucket using crushed fish as bait is requested for sea cucumber farming.
7. Nutrients
content
in
seaweed
Sargassum
densifolium,
seagrass
Thalassodendrom ciliatum and in teguments of juveniles and adults Holothuria
scabra.
Thierry LAVITRA1, Gaetan TSIRESY, Richard RASOLOFONIRINA, Antoine ROUGIER2 & Igor EECKHAUT
(lavitra_thierry@yahoo.fr)
Grounded seaweed Sargassum and sea grass are mostly used to feed sea cucumber Holothuria
scabra juveniles in the hatchery. In the other hand, there is lack of knowledge on the nutrients
content of these seaweed and sea grass which exist in the region (Toliara, southwestern of
Madagascar), nor even for the integuments of H. scabra. This study aimed to determine the nutrients
contents (macro and micro molecules) as well in the seaweed Sargassum densifolium and the sea
grass Thalassodendrom ciliatum as in the integuments of juveniles and adults of H. scabra. Seaweed,
sea grass and adults H. scabra samples were collected directly from the natural environment (Great
Reef of Toliara) while H. scabra juveniles were offered by the MHSA Company. All samples were
transported directly to the laboratory where they were rinsed abundantly with fresh water then kept
at -50°C in the freezer. All analyses are carried out at the chemistry lab of IH.SM except for the
protein content (analysis made in CNRE lab in Antananarivo). The results showed the high protein
content in the integument of H. scabra adults (>30%) against 7% for juveniles and 11,8% and 12,7%
in S. densifolium and T. ciliatum respectively. In the other hand, fat and carbohydrate contents are
very low in all studied samples (<2%). Regarding the micro molecules, the silicate content is very low
in all samples except for T. ciliatum (10,36mg/l). The same remark is made for the nitrate content
except for the integument of farmed H. scabra (7,4mg/l and 16,9mg/l for H. scabra juveniles and
adults respectively). The ammonium and phosphate contents are always less than 1mg/l in all
studied samples. This result would contribute largely to the determination of the appropriate food
that could be used for H. scabra farming in the near future.
8. The use of food compound to rear juveniles of sea cucumber Holothuria scabra
in the external pond.
Thierry LAVITRA1, Gaetan TSIRESY, Richard RASOLOFONIRINA, Antoine ROUGIER2 & Igor EECKHAUT
(lavitra_thierry@yahoo.fr)
The mariculture of edible sea cucumber Holothuria scabra is well developed in the southwestern
region of Madagascar. However problem occurs during the pre-growth stage where juveniles are fed
with sediment collected from the mangrove zone. This sediment should be renewed every month in
order to improve juveniles’ growth. This practice seems to be impossible at industrial level. The idea
is then to identify a food compound to feed H. scabra juveniles during the pre-growth stage. This
study aims to see the effect of the food compound on survival and growth of H. scabra juveniles
reared in the external pond. For this experiment, 4 external ponds of 16m² (4m x 4m) and 0,7m
depth each were constructed. H. scabra juveniles of 4 months old (5g in average wet weight) were
used and the rearing density is of 20 individuals m-2. Each experimentation lasts for 3 months. The
food compound is made of 25% Sargassum densifolium, 05% Thalassodendrom ciliatum, 15%
Kappaphycus alvarezii, 50% fish meal and 5% of corals powder. The results showed that the food
compound does not affect either the survival (p=0,0771) nor the growth (P=0,403) of H. scabra
juveniles reared in the external pond. After 3 months of rearing, their survival rates were very high:
86,80%+/-9,11 and 89,83%+/-9,21 respectively for juveniles fed with marine sediment and fed with
mixture of marine sediment and food compound. Regarding the biomasses, after 3 months of
rearing, they reached 241,11gm-2+/-95,48 and 282,75gm-2+/-133,24 respectively for H. scabra
juveniles fed with marine sediment and with mixture of marine sediment and food compound. Even
no difference was observed statistically for the survival and biomass of H. scabra juveniles fed or not
with the food compound; this result tends to show a slight good effect of this food compound for H.
scabra juveniles farming.
9. AMPA/HOLOTHURIE: a new project funded by the Malagasy Government to
promote sea cucumber farming in Madagascar.
Thierry LAVITRA1, Gaetan TSIRESY, Richard RASOLOFONIRINA, Antoine ROUGIER2 & Igor EECKHAUT
(lavitra_thierry@yahoo.fr)
The sea cucumber farming project pilot “Aqua-lab” was created and established in Toliara
(Southwest of Madagascar) on 1999 through the collaboration between Malagasy (IH.SM, University
of Toliara) and Belgium (ULB and UMons) universities. This project was funded by both Malagasy and
Belgium Government. The second phase of the project is achieved in 2008; then a new company
“Madagascar Holothurie” was created. Since its establishment, the company has worked with a
closed collaboration with NGOs (Blueventures and Transmada Development) and sectorial project
(PACP/IH.SM) in order to promote the mariculture of holothurians in fishermen villages. This
partnership has worked in a platform since 2009 and tried to get financial support together. On 2010,
the Malagasy agency “AMPA” (Agence Malgache pour la Pêche et Aquaculture) has decided to
support the platform and so the project « Applied research for the sea cucumber farming
development in the Southwestern region of Madagascar” was created. This project started to work
on 2011and for 3 years. For the first year of the project, 3 main research axes were developed:
applied, fundamental and socioeconomic researches within what several themes are treated such as
optimization of survival and growth of H. scabra, diversification of the species used for farming,
improvement of the production infrastructures, optimization of the reproduction, study of
socioeconomic changes in the farming villages and so on. The first year of the project was very
successful and the project entered on its second phase on 2013. This year, it will treat other themes
such as tagging and barcoding of sea cucumber, the use of polyaquaculture (sea cucumber and
shrimp farming), the improvement of the process to get better quality final product (trepang) and so
on. This project showed the effective part taken by the Malagasy government for the national
research for the sustainable resource management.
10. Application of benthic diatoms for the biological quality evaluation with the
impact of municipal wastewater of Toliara city (Madagascar) Investigation
about a diatomic index
I. Rasoamananto, E Ranaivoson, L. Ydstebø, G. Lasserre (rasoamananto@yahoo.fr)
Samples of the untreated water were collected from wastewater discharge canals located
throughout the Toliara city, Madagascar every month for 14 months at five different stations. Among
these five stations, a natural spring, Belaza, located 30 km from the city of Toliara was selected as the
control station. Similarly, samples were collected from the effluent of the pond artificial of the
wastewater treatment; however, sampling was occurred three per week for a six-week. To assess the
overall pollution levels of the wastewater canals, average values for each of the physico-chemical
parameters were compared with government established norms. Average values for each of the
physico-chemical parameters were found to lie outside of the normal range. Phosphate and nitrite
measurements indicated a degree of seasonality, with phosphate concentration level increasing
during the rainy season, and nitrite concentration level increasing during the dry season. Monitoring
of the benthic diatoms communities resulted in the identification of a total of 131 species. Among of
those species, four species, including Navicula spp1 and Amphora spp1, were present in the network
of wastewater canals and the control station Belaza throughout most of the study period,
representing ≥1% of the species count. Nitszchia cf palea and Gomphonema parvulum were present
throughout the study period, representing ≥1% of the cell count, however, were observed only at
wastewater sampling stations. Three species, namely Navicula spp1, Nitszchia cf palea,
Gomphonema parvulum, were among the five total species observed in high densities in the wetland
samples, especially downstream of the ponds. The last two species: Nitszchia cf palea, and
Gomphonema parvulum appear promising as potential indicators of pollution in brackish waters,
given their tolerance to pollution and their role played in water purification, and should be the focus
of future research efforts.
11. Development of fish farming in the village of Ambondrolava (ToliaraMadagascar)
Clara, S. G. RAZANAMPARANY, Abigail de Martynoff, Benjamin Taylor, Ylénia, L. RANDRIANARISOA &
Thierry LAVITRA
The small scale fish farming, especially the tilapia farming is still ignored in the South-western region
of Madagascar. In 2011, the NGO HONKO started to develop this activity in Ambondrolava, a village
located 15 km North of Toliara city. In 2012, the same NGO in collaboration with the IH.SM (by the
PRADRA project) launched an experiment in the same village which aimed to compare the survival
and the growth of fingerlings (i) issued from the natural local ponds and those produced from the
hatchery and (ii) reared within two different farming systems (ponds and floating cages). For this
experiment, 8 ponds and 8 floating cages of 6m² surfaces each (2m x 3m) with 1m of depth were
constructed. In each cage and pond, fingerlings of average weight of 4,6g±0,85 (5,3 cm ±0,7 length)
were used. The rearing density was kept at 4 individuals m-2. The food of the livestock is locally made
and was distributed 2 times a day at a rate of 5% of the total biomass. After 8 weeks of rearing, the
results showed that: (i) the survival rate of local fingerlings (80,73%+/-19,28) was really high
compared to this of fingerlings issued from the hatchery (63,54%+/-17,50) (p=0,014) and the survival
rate is better for the fingerlings reared in the floating cages (85,94%+/-12,97) rather than those
reared in ponds (58,33%+/-5,59) (p=0,001); (ii) the fish biomass is generally high for the local
fingerlings (72,96gm-2+/-25,61) compared with that observed from the fingerlings from the hatchery
(50,64gm-2+/-14,49) (p=0,005) and the fingerlings reared in cages present a high biomass (75,82gm2+/-23,78) compared to those reared in ponds (47,77gm-2+/-11,63) (p=0,001). These results tend to
prove the feasibility of small scale tilapia farming in the village where locally fingerlings could be
used. As a farming system, the use of floating cage is suggested.
12. Coral reefs of the South-western region of Madagascar: 56 local based
management reserves
TODINANAHARY Gildas Georges Boleslas, RAKOTOARINIVO William, TSIRESY Gaëtan, LAVITRA
Thierry1, EECKHAULT Igor (todinanaharygildas@gmail.com)
Along the coast from the Mangoky River (latitude 21°24’ S) in the North, to the Onilahy River
(latitude 23°34’ S) in the South, the South-western region of Madagascar represents an important
part of coral reef ecosystems of the Island. Along this coast also live an important fishermen people
with more than 40 fishermen villages. In order to manage efficiently these ecosystems and their
exploitable resources, the Malagasy government, through the PACP (“Projet d’Appui aux
Communautés de Pêcheurs”) project, in collaboration with private NGOs and other public research
institution such as IH.SM, has create from 2006 to 2012, 59 marines reserves which includes 56 coral
reef reserves and 3 mangrove forest. The total surface of the coral reef reserves is 5146 ha. The
creation of these reserves has involved 7 fishermen community based associations which are
becoming managers of the created reserves. In the other hand, village based marine aquaculture has
been developed including sea cucumber farming. To improve the development of the mariculture in
the region, the PRU of the IH.SM proposes also to develop algae (seaweed) and coral farming.
Compared to the seaweed farming, coral mariculture was never been developed in this region. But
will not the large surface of coral reefs and its reserves favor the implementation of this form of sea
farming? Will not that be an additional solution to improve the management of these rich but fragile
ecosystems?
13. Coral farming in Sarodrano (South-western Region of Madagascar): the first
experimental cuttings
TODINANAHARY Gildas Georges Boleslas, TSIRESY Gaëtan, LAVITRA Thierry, EECKHAULT Igor
(todinanaharygildas@gmail.com)
Coral farming is an almost new form of aquaculture in Madagascar. In the South –western region, no
village’s community,no private nor public society has tried to practice the coral farming. However, in
Sarodrano village, where algae and sea cucumber farming are developed, a research project is
undertaken within the “Polyaquaculture Research Unit” (PRU) in order to check out the feasibility
and to develop this new form of marine farming. Two iron coral farming tables have been tested to
support 104 coral fragments set as cuttings. 58 coral cuttings on the first table were exposed to air
(emerged) for about 5 to 10 minutes and 44 coral cuttings on the second table were exposed to air
for less than 1 minute (time to fix the cuttings on their support). Coral species of Acropora were used
for this first experiment. Physical and chemical parameters (temperature, luminosity, salinity and pH)
of the water were regularly measured to find out their correlation with the survival of the corals. And
any observation about disease and/or mortality is made during in-situ observations. Preliminary
results show that the coral cuttings that have been exposed for more than 5 minutes were stressed
(started to bleach) during the 2 first weeks, and those which has not been long exposed were not
bleached. But the corals of the first table started to recover few days after launching and continue to
grow. Only 4 and 3 coral cuttings (respectively) were dead after few days because of the failure of
the support system. This study is continued with special focus on the measure of the stress of the
cuttings using photosynthesis yield analyzer.
14. Study of zooplankton distribution in Sarodrano, South-western Region of
Madagascar: contribution to the coral recruitment and spawning assessment
TODINANAHARY Gildas Georges Boleslas, LAHITSIRESY MAX Gasimandova, TSIRESY Gaëtan, LAVITRA
Thierry, EECKHAULT Igor (todinanaharygildas@gmail.com)
Recently, coral reefs of Sarodrano are among the most studied in the Western Region of Madagascar.
Three of them are newly created marine reserves: Arakaivo, Nosy Velomitahy and Nosy Masaka.
Moreover, coral recruitment and the coral spawning in the South-western Region is studied since
February 2013 by the PRU/IH.SM research project. In order to contribute to this study, a monitoring
of the zooplankton of Sarodrano (latitude 23°30’S) was carried out on these reserves, using 63 µm
mesh plankton net. As the objective is to monitor the temporal distribution of planula larvae,
sampling is made every few days (2 to 5 according to the climatic conditions) after new and full
moon. Samples are preserved with formalin (3% of the volume) before identifying and counting the
plankton with photonic microscope. Results show that the relative abundance of the zooplankton of
Sarodrano is dominated during this period by nauplii larvae (50,1%) followed by tintinnids (27%) and
copepods (14,28%). Globigerina, pteropods, appendicular were also observed in the samples. During
this period, any planula was observed. Considering that the sampling dates correspond to the
suggested periods (few days after full moon), the hypothesis is that any coral spawning happened at
the Nosy Tafara coral reefs from February to April. However, new recruited corals are observed on
recruitment tiles installed in the same area during the same period. These results suggest that the
study should be continued in order to cover at least a reproduction cycle of the corals (1 year) and
different study zones.
15. Coral reefs of the South-western region of Madagascar: localization and
physiography updates.
TODINANAHARY Gildas Georges Boleslas, TSIRESY Gaëtan, LAVITRA Thierry, EECKHAULT Igor &
BEMIASA John (todinanaharygildas@gmail.com)
The South-western region (SWR) of Madagascar is known for its rich marine and coastal ecosystems,
especially the coral reefs. This study aims to gather all the necessary elements, and summarizes in an
updated and illustrated localization and physiography of the corals reefs between the river of
Manombo (latitude 22°58’ S) in the North and the Capricorn tropic (at the river of Onilahy: latitude
23°34’ S) in the South, using marine GIS applications. Used data are composed by satellite data from
the National Oceanographic Data Center (NODC) of Madagascar, and the field measurements of
geographical positioning. The region is divided into three zones from the North to the South: (1) the
Bay of Ranobe, (2) the coastal zone from Fiherenana River to Ifaty village, and (3) the Bay of Toliara.
Each zone respectively presents the following types of coral reef: (1) outer reefs, lagoon reefs and
coral banks; (2) shore reefs; (3) outer reefs including the “Grand Récif de Toliara” which is the greater
reef barrier in the Indian Ocean, inner reefs, coral banks and the Sarodrano reef. In total, the region
has more than 20 of coral reefs: more than 10 in the Bay of Ranobe, 01 long one on the shore from
Fiherenana to Ifaty, and 10 in the Bay of Toliara.
16. Coral recruitment potential, a new chance of regeneration for the Coral reefs of
Sarodrano
TODINANAHARY Gildas Georges Boleslas, TSIRESY Gaëtan, LAVITRA Thierry, EECKHAULT Igor
(todinanaharygildas@gmail.com)
As many coral reef of the South-western Region of Madagascar, the coral reefs of Sarodrano (latitude
23°30’S) are degraded and many species of coral reef‘s communities are threatened. However, any
study of the recruitment potential has been done. This study, undertaken at 3 stations around
Sarodrano (Nosy Tafara : Arakaivo, Nosy Velomitahy and Nosy Masaka aims to update the
monitoring previously made on these reefs using the PRE-COI method, and to check out the
recruitment potential of the sites using the method of recruitment quadrat described in the Global
Coral Reef Monitoring Network Manual. Results show three different situations: Arakaivo is still
preserved with dominance of Acropora species (46%) and other coral groups (23%) and only 31% of
rubble/dead corals and algal assemblage. Nosy Velomitahy and Nosy Masaka are degraded
(respectively 79% and 55% of fragmented dead corals and algal assemblage). However, these two
coral reefs present a large dominance of new recruited corals that are hardly countable with the PRECOI method because of their small size: an average of 26.25 new recruits per scare meter for
individuals less than 2 cm diameter and 11.75 per scare meter for those between 2 to 5 cm
diameters. Arakaivo has 14.45 new recruits per scare meter for individuals with diameter less than 2
cm and 9.7 per scare meter for those between 2 and 5 cm. New recruited species are represented
dominantly by Acroporidae and Pocilloporidae The presence and the abundance of these new
recruited corals on the degraded coral reefs prove that the main causes of the degradation are
fisheries activities of the villagers (anthropic causes). And the regeneration of the coral reefs is
possible with the support of the local management of the coral reefs as reserves that could prevent
the degradation from anthropic causes.