Journal articles
27. HIARA study protocol: impacts of artificial coral reef development on fisheries, human livelihoods and health in southwestern Madagascar
Golden CD, Hartmann AC, Gibbons E, Todinanahary G, Troell MF, Ampalaza G, Behivoke F, David JM, Durand JD, Falinirina AM, Frånberg C, Declèrque F, Hook K, Kelahan H, Kirby M, Koenen K, Lamy T, Lavitra T, Moridy F, Léopold M, Little MJ, Mahefa JC, Mbony J, Nicholas K, Nomenisoa ALD, Ponton D, Rabarijaona RRB, Rabearison M, Rabemanantsoa SA, Ralijaona M, Ranaivomanana HS, Randriamady HJ, Randrianandrasana J, Randriatsara HO, Randriatsara RM, Rasoanirina M, Ratsizafy MR, Razafiely KF, Razafindrasoa N, Romario , Solofoarimanana MY, Stroud RE, Tsiresimiary M, Volanandiana AJ, Volasoa NV, Vowell B, Zamborain-Mason J (2024) HIARA study protocol: impacts of artificial coral reef development on fisheries, human livelihoods and health in southwestern Madagascar. Frontiers in Public Health, 12
Abstract: The Health Impacts of Artificial Reef Advancement (HIARA; in the Malagasy language, “together”) study cohort was set up in December 2022 to assess the economic and nutritional importance of seafood for the coastal Malagasy population living along the Bay of Ranobe in southwestern Madagascar. Over the course of the research, which will continue until at least 2026, the primary question we seek to answer is whether the creation of artificial coral reefs can rehabilitate fish biomass, increase fish catch, and positively influence fisher livelihoods, community nutrition, and mental health. Through prospective, longitudinal monitoring of the ecological and social systems of Bay of Ranobe, we aim to understand the influence of seasonal and long-term shifts in marine ecological resources and their benefits to human livelihoods and health. Fourteen communities (12 coastal and two inland) were enrolled into the study including 450 households across both the coastal (n = 360 households) and inland (n = 90 households) ecosystems. In the ecological component, we quantify the extent and health of coral reef ecosystems and collect data on the diversity and abundance of fisheries resources. In the social component, we collect data on the diets, resource acquisition strategies, fisheries and agricultural practices, and other social, demographic and economic indicators, repeated every 3 months. At these visits, clinical measures are collected including anthropometric measures, blood pressure, and mental health diagnostic screening. By analyzing changes in fish catch and consumption arising from varying distances to artificial reef construction and associated impacts on fish biomass, our cohort study could provide valuable insights into the public health impacts of artificial coral reef construction on local populations. Specifically, we aim to assess the impact of changes in fish catch (caused by artificial reefs) on various health outcomes, such as stunting, underweight, wasting, nutrient intake, hypertension, anxiety, and depression.
26. Assessing recovery potential of coral reefs in Madagascar and the effects of marine protected areas
Randrianarivo M, Gasimandova LM, Tsilavonarivo J, Razakandrainy A, Philippe J, Guilhaumon F, Botosoamananto RL, Penin L, Todinanahary G, Adjeroud M(2024) Assessing recovery potential of coral reefs in Madagascar and the effects of marine protected areas. Regional Studies in Marine Science, Volume 77: 103710, ISSN 2352-4855
Abstract: Large-scale disturbances and local stressors, most notably bleaching events, sedimentation, and overfishing, impact coral reefs around Madagascar. To enhance reef resilience, managers have established several marine protected areas (MPAs) since 1966. Here, we assess the effects of MPAs on the resilience potential of coral reefs using a multi-factor Recovery Index (RI), based on a multi-criteria analysis: the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS). We sampled 18 stations, half of which in unfished areas, along three regions (Masoala in the NE, Nosy-Be in the NW and Salary Nord in the SW) that have been affected by the bleaching event of 2016, the most recent large-scale disturbance. We found a marked variation in RI between regions, with Masoala having the highest RI. We suggest that these results relate to the lower frequency of sea surface temperature anomalies (SSTa) along the east coast and the combination of more frequent SSTa and higher anthropogenic pressures on the west coast. We also found RI variation among stations; most stations with higher RI have high juvenile coral densities, which support important coral replenishment capacities. We further noted a positive effect of MPAs on recovery potential at Nosy-Be. We argue that the effectiveness of MPAs in Madagascar can be increased with Locally Managed Marine Areas, which feature a strong involvement of intended users and are often easier to manage. Our study also demonstrates that TOPSIS can be a useful tool to estimate the recovery capacities of coral assemblages and to support resilience-based conservation actions.
Keywords: Coral assemblages Recovery Index, Marine Protected Areas Management, Coral reefs, Madagascar
25. Differentiation of petro-sourced plastic microfilaments from organic microfilaments by SEM-EDX in environmental samples
Raharinaivo LR, Batignya A, Raquez JM, Mincheva R, Bittencourt C, Maherizo TGF, Todinanahary GGB, Lavitra T, Eeckhaut I (2024) Differentiation of petro-sourced plastic microfilaments from organic microfilaments by SEM-EDX in environmental samples. Marine Pollution Bulletin 205: 116625
Abstract: Quantifying microplastics (MPs) in marine environments is challenging due to the complexities of differentiation from other materials. This study aims to distinguish petro-sourced plastic microfilaments from organic ones in environmental samples using scanning electron microscope coupled with energy dispersive X-ray (SEM-EDX) analysis. Therefore, 38 particles resembling MPs (PRMPs) from sediments and organisms in Madagascar were analyzed. MPs identification thresholds were determined from SEM-EDX analysis of macroplastics and seaweed, the primary sources of microfilaments. SEM-EDX results of the 38 PRMPs were compared with identification/misidentification made by five MPs observation experts. Results indicated that a carbon/oxygen (C/O) ratio >1 distinguished macroplastics and MPs from other sources (seaweed and organic microfilaments). SEM-EDX analysis identified 81.58% of PRMPs as MPs. The average error made by one observer was 36.32%. These findings highlight the need for a method to assess identification error in MPs quantification and recommend SEM-EDX analysis of microfilaments to gauge observer error.
Keywords: Madagascar, Identification, SEM-EDX, Macroplastic, Microplastic, Ratio
24. Local perceptions of the socioeconomic and environmental impacts of sea cucumber farming in southwestern Madagascar.
Lavitra T, Moridy F, Rabearison M, Rodine C, Rakotomahazo C, Nomenisoa ALD, Ranivoarivelo L, Rasolofonirina R, Rakotoarimanana A, Franberg C, Troell M, Eeckhaut I, Todinanahary GGB (2024) Local perceptions of the socioeconomic and environmental impacts of sea cucumber farming in southwestern Madagascar. SPC Beche-de-mer Information Bulletin #44: 48-58
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Abstract: This study explores local perceptions of the socioeconomic and environmental impacts of sea cucumber farming in south- western Madagascar. Among the 298 households surveyed, 69 were actively engaged in sea cucumber farming, participating in sales six to nine times annually, with each farmer selling 43–158 adult sea cucumbers per period. Repurchase prices per village ranged from MGA5 33,660,000 to MGA 150,534,200 per year, corresponding to an average selling price of MGA 2,078,378 per farmer per year. Sea cucumber farming significantly enhances household living conditions, as indicated by impacts such as furniture acquisition, fishing gear, and home construction. Two primary challenges faced by sea cucumber farmers are theft in sea pen enclosures and conflicts over marine space initiated by non-sea cucumber farmers. Regarding environmental impacts, villagers found it challenging to respond comprehensively, primarily noting the attraction and aggregation of various marine animals around sea cucumber enclosures, including juvenile sea cucumbers, finfish, gastropods, bivalves, octopus, shrimp, and squid. In conclusion, sea cucumber farming contributes positively to the standard of living for village farmers in southwestern Madagascar. The engagement of sociologists is imperative for addressing social challenges and fostering the development of this sector.
Keywords: sea cucumber farming, socioeconomic impacts, environmental impacts, household perceptions, southwestern Madagascar
23. Use and management of seagrass ecosystems in southwestern Madagascar
F Rakotonjanahary; C Rakotomahazo; J Nirinamamiko; T Razakarisoa; GGB Todinanahary; T Lavitra; G Lepoint; MA Vanderklift; L Ranivoarivelo (2024) Use and management of seagrass ecosystems in southwestern Madagascar. African Journal of Marine Science, 1–13
Abstract: Madagascar’s seagrass meadows are among the least-studied ecosystems in the western Indian Ocean region. To facilitate sustainable management, understanding the traditional uses of seagrass areas in relation to current management policies is necessary. This study assessed the uses of, and policies relevant to, seagrass ecosystems off southwestern Madagascar. We interviewed 131 community members in five coastal villages around the Bay of Ranobe in Toliara Province. Answers to the survey revealed a good level of awareness of seagrass, though 55% of respondents perceived the status of the seagrass areas as deteriorating. Opinions varied on the source or degree of threats to seagrass, but 74.8% of respondents suggested destructive fishing methods or other factors, including natural phenomena and animal grazing. The responses highlight that seagrass meadows serve as areas important for fishing, seaweed cultivation or sea cucumber farming, and the passage of boat/pirogue transportation. There are currently no tangible policies that directly protect or manage the seagrass areas regarding these activities, although some national regulations and local management initiatives are indirectly relevant, notably no-take zones and the local-level codes known as Dina. Development and implementation of a national management plan for seagrass ecosystems is a key gap. This demands the collection of scientific data to support decision-making to ensure long-term provision of the services provided by seagrass meadows. The involvement of coastal communities in the management of seagrass ecosystems will be necessary for the success of any new policies.
Keywords: Bay of Ranobe, coastal communities, community perceptions, legislation, local knowledge, local resources, survey questionnaire, threats
22. Coral recruitment in the Toliara region of southwest Madagascar: Spatio-temporal variability and implications for reef conservation
Botosoamananto RL, Todinanahary GGB, Gasimandova LM, Randrianarivo M, Guilhaumon F, Penin L, Adjeroud M (2024) Coral recruitment in the Toliara region of southwest Madagascar: Spatio-temporal variability and implications for reef conservation. Marine Ecology e12794
Abstract: Investigating coral recruitment is critical to better understand replenishment and resilience capacities of coral reef ecosystems and to improve their conservation. Here, we examined the spatio-temporal patterns of coral recruitment and the influence of confamilial adult coral cover in the region of Toliara, southwest Madagascar. Terracotta tiles were immersed from October to late January over a 3-year period (2018–2021) at 10 stations located on major reef habitats. Overall recruitment rates were relatively high compared to those of other reefs in the Southwestern Indian Ocean, ranging from 219.20 recruits.m−2 in 2018–2019 to 156.30 recruits.m−2 in 2020–2021. Recruit assemblages were dominated by Acroporidae (45.5%) and Pocilloporidae (45.0%), whereas Poritidae (1.9%) and “other” recruits (3.6%) were rarely recorded. Recruitment patterns varied among stations and habitats, with higher rates in patch reef (187.06 recruits.m−2) and outer slope stations (156.99 recruits.m−2) compared to inner slope stations (108.04 recruits.m−2). With the exception of “other” recruits, recruitment rates decreased between 2018 and 2019 and 2019 and 2020, followed by an increase in 2020–2021 that reached or even exceeded initial values at some stations. The abundance of Pocilloporidae recruits was positively correlated with the cover of confamilial adult corals, highlighting potential stock–recruitment or recruitment–limitation relationships, or an aggregative settlement of young stages near the established adult colonies, whereas no such relationships were recorded for other coral family categories. This study identified sites on the outer slope and patch reefs to consider prioritizing for protection as recruitment hotspots, as well as degraded inner slope sites that could benefit from restoration, with the important caveat that any measures should be accompanied by alternative income-generating activities through local involvement that suits the Malagasy context, such as locally marine managed areas.
21. Thermal sensitivity of black corals (Antipatharia: Hexacorallia): Comparisons between sympatric species from a thermally fluctuating site in Madagascar and between allopatric congenerics
Godefroid M, Vandendriessche M, Todinanahary GGB, Ransquin I, Dubois P (2024) Thermal sensitivity of black corals (Antipatharia: Hexacorallia): Comparisons between sympatric species from a thermally fluctuating site in Madagascar and between allopatric congenerics. Science of The Total Environment, 908: 68311
Abstract:This study investigated factors shaping the thermal sensitivity in antipatharians, a taxon whose members form dense aggregations in all oceans, harbouring a high biodiversity. First, we tested the thermal responses of five sympatric species (Antipathes grandis, Cupressopathes abies, Stichopathes cf. maldivensis, Cirrhipathes anguina and Cirrhipathes cf. spiralis) from the Great Reef of Toliara (Madagascar), using an acute ramping methodology. We then compared the thermal performance curves (TPCs) for oxygen consumption of these five species. Results indicated that phylogeny alone does not explain differences in thermal sensitivity (Antipathidae vs. Myriopathidae). On the contrary, morphology (branched vs. unbranched) appeared as a key factor, with unbranched species (S. cf. maldivensis, C. anguina, C. cf. spiralis) being more tolerant to thermal stress than branched ones (A. grandis and C. abies). Several hypothesis could explain these variations in thermal tolerance across morphology, such as tissue thickness, surface/volume ratio or mass-transfer efficiency. Secondly, we compared the TPC of Stichopathes from Madagascar with those previously obtained in congenerics from the Canary Islands and French Polynesia. This revealed a higher thermal tolerance in the two former than in the latter. It is proposed that it is linked to higher annual temperature variability (but not daily variability) in these two sites compared to French Polynesia. It is concluded that thermal sensitivity in antipatharians is linked to their morphology influencing their physiology and to their thermal history. Phylogeny at the family level plays a less important role in explaining differences in thermal sensitivity in antipatharians.
20. Review: Comparative Environmental Impacts and Development Benefits of Coastal Aquaculture in Three Tropical Countries: Madagascar, Tanzania and Indonesia
Kunzmann A, Todinanahary GGB, Msuya FE, Alfiansah Y (2023) Review: Comparative Environmental Impacts and Development Benefits of Coastal Aquaculture in Three Tropical Countries: Madagascar, Tanzania and Indonesia. Tropical Life Sciences Research
early view : https://ejournal.usm.my/tlsr/article/view/4536
Abstract: Aquaculture is still in early development in Madagascar and Tanzania, while in Indonesia, aquaculture has a long history. In Madagascar, villagers are farming seaweed and sea cucumbers, as part of small-scale community-based aquaculture (CBA). They followed a contractual model between a private farming company and farmers. Local non-governmental organizations (NGOs) and public institutions in Madagascar jointly strive to reverse the trend of ongoing anthropogenic coastal degradation. In Tanzania, the cultivation of red seaweeds has been established for over 30 years, with declining production attributed to climate change. While shrimp farming still involves, to some extent, clearing of mangroves in Tanzania, seaweed culture has only mild impact on coastal ecosystems. Farming areas provide shelter and habitat for juvenile fish, crabs and other organisms. Therefore, NGOs ask for support to improve culture methods. Various problems and shortcomings in Indonesia have been clearly identified, including issues related to new aquaculture areas, pollutants, emerging diseases, insufficient broodstock and fry supply, as well as a lack of technology and manpower. To address these challenges and ensure the growth of aquaculture production, the government has implemented national policies and established training and broodstock centers throughout the country. In Madagascar, the CBA programme stands out as a success story and can serve as a template for other coastal regions and countries. In Tanzania, adoption of the CBA model for co-culture could be the future. In Indonesia, due to a very long coastlines and complicated legislation, IMTA seems to be particularly suitable, as successfully tested in model regions.
Keywords: Tropical Coasts, Livelihood Diversification, Aquatic Ecosystems, Marine Pollution, Seafood
19. Effects of Madagascar marine reserves on juvenile and adult coral abundance, and the implication for population regulation
Randrianarivo M, Botosoamananto RL, Guilhaumon F, Penin L, Todinanahary GGB and Adjeroud M (2023) Effects of Madagascar marine reserves on juvenile and adult coral abundance, and the implication for population regulation. Marine Environmental Research, 190: 106080
Abstract: Recruitment is a critical component in the dynamics of coral assemblages, and a key question is to determine the degree to which spatial heterogeneity of adults is influenced by pre-vs. post-settlement processes. We analyzed the density of juvenile and adult corals among 18 stations located at three regions around Madagascar, and examined the effects of Marine Protected Areas (MPAs). Our survey did not detect a positive effect of MPAs on juveniles, except for Porites at the study scale. The MPA effect was more pronounced for adults, notably for Acropora, Montipora, Seriatopora, and Porites at the regional scale. For most dominant genera, densities of juveniles and adults were positively correlated at the study scale, and at least at one of the three regions. These outcomes suggest recruitment-limitation relationships for several coral taxa, although differences in post-settlement events may be sufficiently strong to distort the pattern established at settlement for other populations. The modest benefits of MPAs on the density of juvenile corals demonstrated here argue in favor of strengthening conservation measures more specifically focused to protect recruitment processes.
Keywords: Coral assemblages, Spatial patterns, Marine protected areas, Recruitment process, Population regulation, Madagascar
18. Wild sea cucumber fishery in southwestern Madagascar
Maka OD, Pascal B, Todinanahary GGB (2022) Wild sea cucumber fishery in southwestern Madagascar. SPC Beche-de-mer Information Bulletin #42: 36-45
Abstract: Sea cucumbers have been overexploited in southwestern Madagascar, and some measures have been established for sustainably managing them. Since these management measures have been in place, however, very few assessments of the holothurian fishery have been made. From January to December 2018, we performed an assessment of fishery activities (fishing effort, catches, processing and marketing of products), and governance analysis at three main holothurian fishing villages (Sarodrano, Ankiembe and Andrevo). The results show that 12 species of sea cucumbers are collected by fishers in the study area. Compared to previous studies (Rasolofonirina and Conand 1998; Rasolofonirina et al. 2004), catches have increased, althoughthese mainly comprise Holothuria notabilis (95.4% of catches for Andrevo, 95.4% for Ankiembe and 60.2% for Sarodrano), which have a low commercial value. Three forms of holothurian commercial chains were identified involving fishermen, middlemen, fishmongers and private operators. Fishmongers and/or fishermen take care of the first part of the processing (evisceration, first cooking, salting and second cooking), and operators complete the process to obtain exportable trepang. The holothurian fishery in southwestern Madagascar is developing but some of the established measures for their management and governance are poorly applied. Thus, it is recommended to improve aspects of their governance and to reinforce and renew existing management systems.
Keywords: sea cucumber fishery, management, governance, southwestern Madagascar
17. A contemporary baseline of Madagascar's coral assemblages: Reefs with high coral diversity, abundance, and function associated with marine protected areas
Randrianarivo M, Guilhaumon F, Tsilavonarivo J, Razakandrainy A, Philippe J, Botosoamananto RL, Penin L, Todinanahary GGB and Adjeroud M (2021) A contemporary baseline of Madagascar’s coral assemblages: Reefs with high coral diversity, abundance, and function associated with marine protected areas. PLOS ONE, 17(10): e0275017.
Abstract: Madagascar is a major hotspot of biodiversity in the Western Indian Ocean, but, as in many other regions, coral reefs surrounding the island confront large-scale disturbances and human- induced local stressors. Conservation actions have been implemented with encouraging results for fisheries, though their benefit on coral assemblages has never been rigorously addressed. In this context, we analyzed the multiscale spatial variation of the composition, generic richness, abundance, life history strategies, and cover of coral assemblages among 18 stations placed at three regions around the island. The potential influences of marine pro- tected areas (MPAs), algal cover, substrate rugosity, herbivorous fish biomass, and geo- graphic location were also analyzed. Our results highlight the marked spatial variability, with variation at either or both regional and local scales for all coral descriptors. The northeast coastal region of Masoala was characterized by the high abundance of coral colonies, most notably of the competitive Acropora and Pocillopora genera and stress-tolerant taxa at several stations. The southwest station of Salary Nord was distinguished by lower abundances, with depauperate populations of competitive taxa. On the northwest coast, Nosy-Be was character- ized by higher diversity and abundance as well as by high coral cover (~42–70%) recorded at unfished stations. Results clearly underline the positive effects of MPAs on all but one of the coral descriptors, particularly at Nosy-Be where the highest contrast between fished and unf- ished stations was observed. Biomass of herbivorous fishes, crustose coralline algae cover, and substrate rugosity were also positively related to several coral descriptors. The occurrence of reefs with high diversity, abundance, and cover of corals, including the competitive Acro- pora, is a major finding of this study. Our results strongly support the implementation of locally managed marine areas with strong involvement by primary users, particularly to assist in man- agement in countries with reduced logistic and human resources such as Madagascar.
16. Exploring the policy and institutional context of a Payment for Ecosystem Services (PES) scheme for mangroves in southwestern Madagascar (2022)
Rakotomahazo C, Ranivoarivelo NL, Razanoelisoa J, Todinanahary GGB, Ranaivoson E, Remanevy ME, Ravaoarinorotsihoarana LA and Lavitra T (2021) Exploring the policy and institutional context of a Payment for Ecosystem Services (PES) scheme for mangroves in southwestern Madagascar (2022). Marine Policy, 148 (105450)
Abstract: Although Payments for Ecosystem Services schemes emerged since the 1980′s to manage forest ecosystems, their application to mangrove forests is still recent, and evidence of their effectiveness is still questioned towards the complex legal status of mangroves. This study explored the context of policy and institution regarding the Payment for Ecosystem Services (PES) implemented in the mangroves of the Southwestern Madagascar. We used Policy content analysis to examine the interactions between the Madagascar sectoral policies and the PES design frameworks developed under the Reduction of Emission from Deforestation and forest Degradation (REDD+) mechanism of the United Nations Framework Convention on Climate Change. In addition, semi-structured interviews with national and local stakeholders were conducted to identify i) institutional interplay between PES and mangroves and ii) challenges faced with the implementation of PES in the mangroves. We found that environmental, fisheries and land use planning policies that concern mangrove management are coherent with the frameworks and supportive of PES implementation. Lack of clear legal frameworks and coordination between the sectoral ministries, weakness of government organisations due to political instability, and limited local governance capacity are the major challenges for the implementation of PES schemes in mangroves. These led to lower motivation to collaborate in mangrove conservation efforts among the members of local communities. We emphasized that the existence of the mangrove PES initiative like in the Baie des Assassins could be a catalyst for Madagascar to develop clear policy, legislation, and institutions to support effective implementation of the PES schemes in mangroves.
Keywords:Mangroves, Policy, Legal framework, Payment for Ecosystem Services, Baie des Assassins
15. Spatial Patterns of Coral Community Structure in the Toliara Region of Southwest Madagascar and Implications for Conservation and Management
Botosoamananto RL, Todinanahary GGB, Razakandrainy A, Randrianarivo M, Penin L and Adjeroud M (2021) Spatial Patterns of Coral Community Structure in the Toliara Region of Southwest Madagascar and Implications for Conservation and Management. Diversity 13(10), 486
Abstract: The Great Reef of Toliara, on the southwestern coast of Madagascar, has been documented as harbouring flourishing reef communities in the 1960s, but has since been affected by various threats, causing a coral decline last reported in 2008. In 2017, we examined the spatial heterogeneity in coral community structure in the region of Toliara. Coral assemblages were characterized by a marked spatial variability, with significant variation for most of the descriptors among the three major habitats and also among stations within habitats. We recorded high coral cover, with values >40% at six of the 10 stations, which was associated with high abundance of coral colonies. We also documented the return to an Acropora-dominated coral assemblage. While these positive results suggest a recent return to healthier coral assemblages, they must be tempered, as the diversity that we recorded was lower than in the 1960s. Moreover, we found a high cover of algae at several stations, suggesting that the ecosystem is likely close to the tipping point toward a phase shift. Finally, the population size-structure of major coral taxa was positively skewed, with few large colonies to ensure the replenishment of local populations. The marked spatial variation suggests that marine protected areas should integrate a sufficiently large area to capture the scale of this spatial heterogeneity.
Keywords: coral reefs; scleractinian corals; community structure; spatial variability; Madagascar
14. Perspectives on working underwater with black coral nubbins (Cnidaria: Antipatharia): the case of Cirrhipathes anguina (Dana, 1846)
Godefroid M, Todinanahary GGB, Dubois P, Eeckhaut I, Lepoint G, Terrana L (2021) Perspectives on working underwater with black coral nubbins (Cnidaria: Antipatharia): the case of Cirrhipathes anguina (Dana, 1846). Journal of Experimental Marine Biology and Ecology
Abstract: In order to test the feasibility of transplantation of the whip black coral species Cirrhipathes anguina (Dana, 1846) from Madagascar, transplants were installed on cultivation tables in two sites (the North Pass and the Grande Vasque) characterized by distinct environmental conditions. Following transplantation, the transplants were followed for short-term (20 days) healing capacities and medium-term (200 days) mortality and growth rates. Results show a successful transplantation in both sites with 0% mortality (except in the form of missing fragments) and a certain growth over 200 days. Maximum growth rates were 3.4 cm/month and 2.0 cm/month in the North Pass and in the Grande Vasque, respectively. In addition, mean time to total healing was delayed in the Grande Vasque compared to the transplants in the North Pass (10 days). Differences between sites are likely to be related to differences in environmental parameters. Altogether, the promising results obtained with the easy protocol used in this study encourage the use of black coral transplants in further in situ experiments and restoration projects.
Keywords: Black corals, Transplants, Growth, Healing, Cirrhipathes anguina, Madagascar
13. Improvement of live coral shipping conditions using an illuminated box
Todinanahary, G.G.B., Batigny, A., Lavitra, T., Grosjean, P. (2021). Improvement of live coral shipping conditions using an illuminated box. Western Indian Ocean Journal of Marine Science, 20(2):81-93
Abstract: The transportation of live coral nubbins is a major constraint of the coral trade. Corals must be transported within a timeframe of <20 hours using concentrated oxygen to avoid high post-transportation mortality. To understand the effects of transportation water quality on coral nubbin growth and post-transportation mortality, a series of trans- portation simulations were performed on Seriatopora hystrix. Different water volumes (dry method, 125 ml, 190 ml, and 325 ml) and oxygen concentrations in the gas phase (21 %, 40 %, and 85 %) were tested, and a 24 LED Handy Lamp was added to provide light irradiance of >100 μmol m-2 s-1 in the transportation box. During transportation nubbins extracted calcium carbonate for growth reducing water alkalinity and consequently pH to 6.67. Dissolved oxygen concentration also rapidly decreased to 0.19 mg L-1. The concentration of inorganic nitrogen, particularly ammo- nium ions, increased after 24 hours and reached very high concentrations after 48 hours. Before 48 hours, the larger the water volume and oxygen concentration, the faster the nubbin growth after transportation. Beyond 48 hours, in all cases, reduction in water quality became critical for nubbins and resulted in partial mortality. Illuminating the transportation box improved water quality for 72 hours using normal air.
Keywords: coral transportation, Seriatopora hystrix, light irradiance, resistance
12. Ecomechanics of Black Corals (Cnidaria: Anthozoa: Hexacorallia: Antipatharia): a Comparative Approach
Dugauquier J-M, Godefroid M, M’Zoudi S, Terrana L, Todinanahary GGB, Eeckhaut I, Dubois P (2021) Ecomechanics of Black Corals (Cnidaria: Anthozoa: Hexacorallia: Antipatharia): a Comparative Approach. Invertebrate Biology
Abstract: Mechanical properties of the skeleton of four antipatharians (the whip species Cirrhipathes anguina and Stichopathes cf. maldivensis, and the branched species Cupressopathes abies and Cupressopathes cf. pumila) living in shallow waters off the southwestern coast of Madagascar were investigated using a three-point bending test. The Young’s modulus did not differ according to species but was significantly higher in the distal segment of colonies, compared with the basal and median seg- ments. By contrast, the flexural stiffness was significantly higher in whip species com- pared with branched ones, and in the whip species, flexural stiffness was higher in the basal segment compared with the other two segments, an observation consistent with a specific adaptation of the species to a strong current environment. Although both species cohabit identical flow conditions, whip species are able to maintain their stalk in vertical position, whereas branched species can readily bend over. This sug- gests that the specific flexural stiffness is linked to contrasting feeding strategies of species with different morphologies in a similar strong current environment.
Keywords: antipatharians, biomechanics, flexural stiffness, Madagascar, Young’s modulus
11. First evaluation of coral recruitment in Madagascar
Todinanahary GGB, Hasintantely N, Eeckhaut I, Lavitra T (2021) First evaluation of coral recruitment in Madagascar. Western Indian Ocean Journal of Marine Science, 20(1):47-62
Abstract: The distribution of larvae and recruitment of scleractinians in the southwest region of Madagascar were evaluated for the first time between October 2013 and September 2014 at 3 sites. The presence of coral larvae (planulae) was monitored through weekly sampling using a plankton net and the recruitment rate evaluated by monthly sampling of the newly settled corals (<1 year stage) on recruitment tiles and by a monitoring of the recruitment of juveniles (1< Juveniles < 2 years) using the quadrat method. Planulae were present in the plankton for 9 months during the survey. The recorded mean annual density of planula varied from 0.43 ± 0.41 larvae m-3 to 3.23 ± 5.72 larvae m-3 depending on site, with a peak in larval density towards the end of November and the beginning of December. The variability in the occurrence of planula is very high and implied that the density observed in the year does not present a significant difference between the sites (pKW=0.33). The average density of total recruits was 620.13 ± 621.30 recruits m-2, 40.28 ± 50.97 recruits m-2 and 36.34 ± 33.82 recruits m-2, respectively at the sites of Nosy Tafara, Grande Vasque and Rose Garden. Seasonal distribution of coral recruitment was different between the sites. The mean annual density of newly settled recruits (< 1 month stage) was significantly higher at Nosy Tafara with 94.91±101.08 recruits m-2 compared to Grande Vasque and Rose Garden with 18.75±34.32 recruits m-2 and 11.57±18.47 recruits m-2 (pKW<0.001), respectively. The highest density of newly settled recruits was observed between October to December. Higher density of recruits was also observed in March at Nosy Tafara and in May at all three sites. Results of juvenile monitoring showed high rates (> 10 juveniles m-2) compared to other regions and the threshold, but it revealed high mortality among recruits. Coral recruitment in the southwest region of Madagascar was found to be high and could result in increased resilience of the coral reef assemblages.
Keywords: recruitment, planula, recruits, juveniles, scleractinians, Madagascar
10. Community Perceptions of a Payment for Ecosystem Services Project in Southwest Madagascar: A Preliminary Study
Rakotomahazo C, Razanoelisoa J, Ranivoarivelo NL, Todinanahary GGB, Ranaivoson E, Remanevy ME, Ravaoarinorotsihoarana LA and Lavitra T (2021) Community Perceptions of a Payment for Ecosystem Services Project in Southwest Madagascar: A Preliminary Study. Land 10: 597
Abstract: Despite the popularity of Payment for Ecosystem Services (PES) schemes as a new paradigm to enhance conservation of natural resources, evidence of their benefits to people and nature is often illustrated from desk-based reviews, but rarely investigated from the local sites where they have been implemented. We investigated local perceptions of a PES scheme implemented in the Baie des Assassin’s mangroves of southwest Madagascar with particular focus on its perceived future effects. To meet our goal, we first collated socioeconomic and mangrove ecological information through extensive literature research, and key informant interviews with 35 peoples within the 10 villages surrounding the bay to be used as reference conditions. Following this, a workshop with 32 participants from local communities was conducted, using participatory scenario planning to predict the effects of the PES project, and to identify concerns surrounding its implementation. Local communities perceived the PES scheme as a potentially valuable approach for the sustainable management of their mangroves, and perceived that it would address major socioeconomic issues and mangrove management problems in the bay as a result of the carbon offsetting from their mangroves. We conclude that to achieve acceptance and good governance of a PES project by local communities, needs and concerns surrounding the implementation of the PES project need be addressed.
Keywords: mangroves; biodiversity; ecosystem services; scenario planning; Baie des Assassins
9. Community Perceptions of a Payment for Ecosystem Services Project in Southwest Madagascar: A Preliminary Study
Delroisse J, Van Wayneberghe K, Flammang P, Gillan D, Gerbaux P, Opina N, Todinanahary GGB, Eeckhaut I (2020) Epidemiology of a SKin Ulceration Disease (SKUD) in the sea cucumber Holothuria scabra with a review on the SKUDs in Holothuroidea (Echinodermata). Scientific Reports 10: 22150
Abstract: Aquacultivated sea cucumbers often suffer from SKin Ulceration Diseases (SKUDs). SKUDs have been observed in six holothuroid species from nine countries. All SKUDs present a similar symptom— the skin ulceration—and can be induced by bacteria, viruses, or abiotic factors. We here provide an update on SKUDs in holothuroids and analyse the case of the SKUD observed in Holothuria scabra in Madagascar. Field observations revealed a seasonality of the disease (i.e. wintertime maximum peak). Morphological analyses of integument ulcers showed that sea cucumbers react by forming a collagen fibre plug. Metagenomic analyses revealed a higher proportion of Vibrionaceae (Gammaproteobacteria) in ulcers in comparison to the healthy integument of the same individuals. Experimental infection assays were performed with ulcer crude extracts and bacteria isolated from these extracts (e.g. Vibrio parahaemolyticus) but did not significantly induce skin ulceration. Our results suggest that the disease is not induced by a pathogen or, at the very least, that the pathogen is not found within the ulcers as the disease is not transmissible by contact. An initial cause of the SKUD in Madagascar might be the repeated and prolonged exposures to cold temperatures. Opportunistic bacteria could settle in the dermis of ulcerated individuals and promote the ulcer extension. We propose a general nomenclature for SKUDs based on the acronym of the disease, the affected sea cucumber species (e.g. Hs for Holothuria scabra), the concerned region using an ISO code 3166-2 (e.g. MG for Madagascar), the description date (e.g. 20 for the year 2020), and, when known, the inducing agent (first letter of the general taxon, b for bacteria, v for virus in currently known cases; a a if it is an abiotic inducing parameter; nothing if the inducing cause has not been precisely identified). The disease described in this work will be designated under the name SKUD Hs-MG-20.
8. Impact of Thalamita crenata (Decapoda; Portunidae) predation on Holothuria scabra juvenile survival in sea farming pens
Eeckhaut I, Février J, Todinanahary G, Delroiesse J (2020) Impact of Thalamita crenata (Decapoda; Portunidae) predation on Holothuria scabra juvenile survival in sea farming pens. SPC Beche-de-mer Information Bulletin #40: 11-16
Abstract:
We evaluate the impact of predation by the crab Thalamita crenata on Holothuria scabra juvenile survival in a sea farming site in Madagascar where crab predation pressure is high. Three experiments were carried out: the first was conducted to estimate the survival of sea cucumber juveniles of different body masses when placed in open enclosures; the second compared the survival of juveniles placed in opened and closed enclosures; and the third evaluated the survival of juveniles when placed in the presence of crabs in closed enclosures. Holothuria scabra juveniles were of a body mass between 1 and 80 g. The results showed that predation by T. crenata is a key parameter to take into account when farming H. scabra. The seeding of juveniles at sea should be performed with large individuals weighing at least 30 g to avoid predation.
7. Participatory planning of a community-based payments for ecosystem services initiative in Madagascar's mangroves
Rakotomahazo C, Ravaoarinorotsihoarana LA, Randrianandrasaziky D, Glass L, Gougha C, Todinanahary GGB, Gardnera CJ (2019) Participatory planning of a community-based payments for ecosystem services initiative in Madagascar’s mangroves. Ocean and Coastal Management, 175: 43-52.
Abstract: Although the dynamics of coastal resources are largely determined by the impacts of human users, spatially-explicit social data are rarely systematically integrated into coastal management planning in data-poor developing states. In order to plan a community-based mangrove payments for ecosystem services initiative in southwest Madagascar, we used two participatory approaches; public participation geographic information systems and concept modelling workshops – with 10 coastal communities to investigate the dynamics and spatial distribution of the mangrove resources they use. In each village we conducted participatory mapping of land and resource use with different livelihood groups using printed satellite images, and concept modelling workshops to develop concept models of the mangrove social-ecological system (including the identification of threats and underlying drivers, and proposals for targeted management strategies). Each community then proposed mangrove zoning consisting of strict conservation zones, sustainable use zones and restoration zones. Following validation and ground-truthing, the proposed zones and management strategies formed the basis of the zoning and management plan for the mangrove. Participatory approaches proved a simple and reliable way to gather spatial data and better understand the relationships between the mangrove and those who use it. Moreover, participation stimulated mangrove users to consider resource trends, the impacts of their activities, and required management actions, promoting a collective ‘buy-in’ for the project. Since participation extended beyond research to the development of management zones, rules and strategies, we believe that community ownership of the project has been strengthened and the chances of successfully conserving the mangrove improved.
Keywords: Community-based natural resource management, Concept modelling, Conservation, Participatory mapping Public participation GIS
6. Previously unlisted scleractinian species recorded from the Great Reef of Toliara, southwest Madagascar
Todinanahary GGB, Refoty ME, Terrana L, Lavitra T, Eeckhaut I (2018) Previously unlisted scleractinian species recorded from the Great Reef of Toliara, southwest Madagascar. WIO Journal of Marine Science, 17 (2): 67 – 77
Abstract: The scleractinian biodiversity of Madagascar is mainly known from one study performed in the Bay of Toliara (SW of Madagascar) in the 1970s. In the present study, this biodiversity was re-investigated 40 years later, at 2 sites previously considered as atypical, but now subject to high anthropogenic pressures. Results showed lower species diversity compared to the previous study, and to similar sites in the Indian Ocean region, but most of the well-represented genera were recorded. The occurrence of previously unrecorded species suggests that the scleractinian communities are changing, in addition to declining. The findings of the present study constitute a baseline of scleractinian structure studies, focused on diversity change. Further investigations on this reef must consider these changes, and management measures must be adapted to ensure greater efficiency.
Keywords: newly recorded species, scleractinians, biodiversity, Great Reef of Toliara, southwest Madagascar
5. Potential influence of phytoplankton density on doliolaria and pentactula appearances in sandfish hatcheries
Todinanahary GGB, Fohy N, Andriatsialonana C, Eeckhaut I (2018) Potential influence of phytoplankton density on doliolaria and pentactula appearances in sandfish hatcheries. SPC Bêche-de-mer Bulletin
Abstract:
The present study reports on the influence of phytoplankton food density on the time of appearance of doliolaria and pentactula. 72 h-old auricularia of Holothuria scabra were used at the beginning of the experi- ment. Two different food concentrations were used during the larval rearing: ~1500 cells mL-1 day-1 (F1) and ~120 cells mL-1 day-1 (F2). Results show that doliolaria appears significantly – ca 7 days – earlier with F1. Pentactula appears from 22 ± 6.6 days with F1, while with F2 they appear after 29.8 ± 9.3 days, but the difference is not significant. The results suggest that when the sea water is saturated with food (as in F1), the density of auricularia does not affect the larval life span (time of appearance of doliolaria). With low food concentration (as in F2), when the larval density is high, the quantity of food in the medium remains low, suggesting that food competition occurs between the larvae and slows down their development into doliolaria and pentactula.
4. Inventaire et étude de faisabilité de sites propices à l’algoculture, l’holothuriculture, la gestion de l’exploitation de poulpes et de crabes dans la Région Atsimo Andrefana
Todinanahary GGB, Behivoke F, Nomenisoa AL, Ravelojaona DK, Rakotoson AT, Tatangirafeno S, Rakotonjanahary F, Tsiresy G, Mara ER, Eeckhaut I, Lavitra T (2017) Inventaire et étude de faisabilité de sites propices à l’algoculture, l’holothuriculture, la gestion de l’exploitation de poulpes et de crabes dans la Région Atsimo Andrefana. Rapport d’étude, MHSA – PRU (Contrat n° 166/C/PIC2/2016), 357 p.
Abstract: L’inventaire et l’étude de faisabilité des sites propices à l’algoculture, à l’holothuriculture et à la gestion de l’exploitation de poulpes et crabes dans la région Atsimo Andrefana, réalisés par MHSA-PRU, ont été conduits dans l’optique de favoriser la croissance économique de la Région/Nation par l’identification de nouveaux sites favorables pour l’expension de l’aquaculture et d’autres produits d’exportation. Quatre communes rurales ont été prospectées : la commune rurale de Belalanda et la commune rurale de Manombo-Sud qui se trouvent dans la Baie de Ranobe, la commune rurale de Tsifota et la commune rurale de Befandefa au Nord. Les villages qui composent ces communes rurales sont des localités de pêcheurs dont les activités principales sont intimement liées à la pêcherie récifale. Au moins une séance de cartographie participative et un focus group ont été réalisés au niveau de chaque village pour collecter les connaissances et expériences des communautés. Des prospections en mer ont été ensuite effectuées pour identifier les sites in situ. Des entretiens et enquêtes individuelles ont été effectués dans chaque village pour compiler les données qualitatives et quantitatives. Avant, pendant et après les prospections sur terrain, l’équipe a rencontré les acteurs des 4 filières dans la Région. Ces rencontres avaient pour objectifs de présenter la présente étude et de solliciter ces acteurs à la contribution par rapport à leurs activités liées à l’étude. Ces acteurs sont les principaux intervenants ayant une expérience pratique concernant l’algoculture, l’holothuriculture, la gesion des poulpes et des crabes. Les principaux acteurs travaillants dans la Région Atsimo Andrefana sont, à part les autorités administratives publiques, les institutions de formation et de recherche (IH.SM, Université de Toliara), les opérateurs privés (COPEFRITO, MUREX International, OCEAN), les ONG (Reef Doctor, WCS, Blue Ventures) et les communautés villageoises. Au niveau des 4 communes rurales étudiées, 49 villages littoraux ont été investigués, parmi lesquels 34 présentent des sites propices à l’algoculture, 13 pour l’holothuriculture, 37 pour les sites d’exploitation de poulpes et 10 villages pour l’engraissement de crabe. Par rapport aux 4 filières en question, toute la zone de la Baie de Ranobe est gérée par des associations communautaires (Figure 1) avec l’appui de différentes ONG (e.g., Reef Doctor, Honko2) et en partenariat avec des sociétés privées (e.g., COPEFRITO, MUREX et IOT). La zone entre le village de Tsandamba et celui d’Andravona est gérée par l’association SOARIAKE, avec l’appui de l’ONG WCS, la zone Nord, jusqu’au village de Nosy Be est gérée par 2 associations (MANJABOAKE et VELONDRIAKE), avec l’appui de l’ONG Blue Ventures.
3. Community-based coral aquaculture in Madagascar: A profitable economic system for a simple rearing technique?
Todinanahary GGB, Lavitra T, Andrifanilo HH, Puccini N, Grosjean P, Eeckhaut I (2017) Community-based coral aquaculture in Madagascar: A profitable economic system for a simple rearing technique?
Abstract: Since a couple of decades, coral aquaculture has been developed in many countries to face an increasing live coral market and to support conservation of endangered natural coral reefs. To evaluate the potentiality of community- based coral aquaculture in Madagascar, we experienced suitable farming techniques using the species Acropora nasuta and Seriatopora caliendrum. Survival and growth rate of the nubbins were monitored during wet, warm and dry, cold seasons. To determine economical feasibility, the coral market was investigated and the yields were also calculated using the technical, biological and social parameters of the production. Coral nubbins were reared in situ at appropriate conditions. Coral nubbins reared during the wet, warm season showed a final survival rate of 67 ± 6% and 57 ± 4% respectively for A. nasuta and S. caliendrum, while in the dry, cold season, the survival rates were of 85 ± 7% and 69 ± 1% respectively. A. nasuta had a significantly higher survival rate than S. caliendrum during both seasons. During the wet, warm season, growth rates were 0.46 ± 0.16% d− 1 and 0.54 ± 0.16% d− 1 respectively for A. nasuta and S. caliendrum. In the dry, cold season, A. nasuta had 0.63 ± 0.18% d−1 of growth rate, while S. caliendrum grew 0.65 ± 0.15% d−1. Significant difference was observed between both species during the wet, warm season, but not during the dry, cold season. Furthermore, both species grew faster during the dry, cold season. These results are in the range of reference values for corals. The activity can be profitable from 25 coral nubbins sold per month. Profit can already be perceived from the second year and a total of more than EUR 27,000 earned after 5 years of developing project, for an initial investment of EUR 1978. Marine animals wholesale companies and biodiversity conservation NGOs seem to be the appropriate clients for this form of aquaculture on Madagascar.
Statement of relevance: This paper provides new form of coral aquaculture: the community-based coral aquaculture. The socially and environmentally responsible production of coral is among the benefits of this new economically viable form of aquaculture.
Keywords: Community-based, Coral aquaculture, Economy, Conservation, Madagascar
2. First records of illegal harvesting and trading of black corals (Antipatharia) in Madagascar
Todinanahary GGB, Terrana L, Tsiresy G, Eeckhault I, Lavitra T (2016) First records of illegal harvesting and trading of black corals (Antipatharia) in Madagascar. Journal of Madagascar Conservation and Developpement, 11: 1
Abstract: Black corals (Cnidaria: Antipatharia) have been used all around the world for a long time, whether as money or for medicinal pur- poses and jewellery manufacturing. Except in Hawaii where these fisheries are well known, black coral harvests are usually made without any control or any management. This is the case in many tropical islands and particularly in Madagascar, where the illegal trade is continually expanding. Since 2011, an illegal traffic of black corals has been occurring in the main cities of the southern and coastal regions of Ambovombe and Tolagnaro. In 2014 and 2015, hundreds of kilograms of black coral skeletons and a lot of diving material were seized by the authorities in the Anosy and Androy regions. Despite this and the continual harvesting of these natural resources, there has been no study of the excessive ex- ploitation in this region. This paper is the first to talk about this new threat and to analyse and discuss the benefits of these fishe- ries. The first seizures and the efforts carried out on the island to stop the trade are explained. This paper highlights the urgency of studying these corals before making an appropriate conservation and management plan.
1. Characteristics of the infestation of Seriatopora corals by the coral gall crab Hapalocarcinus marsupialis Stimpson, 1859 on the Great Reef of Toliara, Madagascar
Terrana L, Caulier G, Todinanahary G. Lepoint G, Eeckhaut G (2016) Characteristics of the infestation of Seriatopora corals by the coral gall crab Hapalocarcinus marsupialis Stimpson, 1859 on the Great Reef of Toliara, Madagascar. Symbiosis
Abstract:
This study describes the association between the obligatory symbiont coral gall crab Hapalocarcinus marsupialis and its stony coral hosts Seriatopora sp. within the Great Reef of Toliara in Madagascar and attempts to dis- cuss their symbiotic status through comparison with previous studies. These corals are inhabited by crabs living in galls that can be categorised in four distinct morphological stages, where the first one corresponds to a small bud and the last one represents a completely closed gall surrounding the crab inside. Within the reef, 563 colonies of Seriatopora species were observed by scuba-diving at ten different stations: 37.8 % of them were infested by H. marsupialis, with a total of 763 galls, and with a majority of stage 4 galls. Galls are monopolised by females that can have different morphologies. Females store the sperm in two spermathecae and are fertilised when their morphology and size are similar to males and the gall is not closed. Histological observations coupled with scanning electronic microscopy analyses show that closed galls are made of an external living tissue, a mid skeletal layer and an internal living tissue. The internal living tissue includes polyps similar to the external tissue, some of them being sex- ually mature. Nitrogen and carbon isotopic signatures
confirmed that these crabs are filter-feeders and do not feed on their host. This association perfectly highlights the difficul- ties to define the symbiotic status of a symbiont if one con- siders inflexible the three categories of symbiosis commonly defined.
Keywords : Coral gall crab, Stony coral, Cryptochiridae, Madagascar