High sea - Mini-symposium - WIOMSA symposium 2022

The contribution of marine science in areas beyond national jurisdiction in the Western Indian Ocean to the development of a regional ocean governance strategy

In partnership with the SAPPHIRE program, led by the Nairobi Convention, this mini symposium will highlight how advances in oceanographic research in the Western Indian Ocean (WIO) can be used to inform aspects of a regional strategy for ocean governance, particularly as it relates to the conservation and management of biodiversity beyond national jurisdictions (BBNJ).

It will provide information on a topic of regional importance, i.e., scientific information on areas beyond national jurisdictions (BBNJ) of the Western Indian Ocean (WIO) littoral states, which is currently relatively limited and poorly distributed and shared. The contribution of this information to a regional strategy to improve ocean governance in the WIO will be primarily to ensure that the importance of maintaining marine biodiversity in a healthy state to provide the basis for a sustainable blue economy is emphasized and integrated.

Comoros - poster WIOMSA symposium 2022

Monitoring coastal vulnerability to marine erosion in Comoros

Nourddine MIRHANI (CUP, Univ. of Comoros) ; Matthieu LE DUFF (Univ. center in Mayotte) ; Yann MERCKY (Univ. center in Mayotte); Espérance CILLAURREN (IRD, UMR Espace Dev) ; Gilbert DAVID (IRD, UMR Espace Dev)

Erosion affects a large part of the WIO coastlines and it is likely to increase in the future with the sea level rise driven by global warming. In this context, monitoring coastal erosion is a key tool for planning policies to adapt to global warming at the regional, national and local levels. Comoros islands are particularly exposed and vulnerable to coastal erosion. Coastal monitoring focuses on coastal vulnerability and deals with low-cost and participatory methods.

WIO Science and civil society - oral presentation WIOMSA symposium 2022

Empowering children to make informed decisions in the SW Indian Ocean: analysis of the Educational Marine Areas program

Authors : Georgeta Stoica (CUFR Mayotte); Philippe Charpentier (CUFR Mayotte); Lola Massé (IRD UMR Espace-Dev); Christelle Morel (Réserve Naturelle Marine de la Réunion); Karine Pothin (Réserve Naturelle Marine de la Réunion); Allen Cedras (Seychelles Parks and Garden Authority); Pascale Chabanet (IRD, UMR Entropie)

An Educational Marine Area (EMA) is a relatively new concept in environmental education established in 2012 in the Marquesas Islands (French Polynesia). It represents an educational programme and environmental awareness concept that implies the participatory management of a coastal marine area by pupils of primary schools. EMAs aim at enforcing the link between Science and Society and empowering children for better decision-making in issue related to the protection of the marine environment.

Madagascar -  poster WIOMSA symposium 2022

Overview of the fish assemblage through the small-scale fishing analysis in the Betsiboka estuary, northwestern Madagascar

Tsirilaza Benjamin (Univ. Tuléar), Andriambeloson Johary Andriamihaja (IOGA) ; Rasoloariniaina Jean Robertin (Institut d’Enseignement Supérieur d’Antsirabe) ; Andriamirado Rabarison Guy Arthur (CNRE)

The estuary and delta is a transition zone between the continental and oceanic environment. Studies on fish population in deltaic and estuarine areas have a social and economic importance because these specific estuarine systems are under threats linked to the expansion of human activities. The fish assemblage is explored by fishing practices in the Betsiboka delta and estuary, to complete the previous studies on sedimentology, biochemistry and mangrove ecosystem. The study on estuary fish assemblage requires knowledge of salinity gradient due to a change in salinity will influence the fish distribution and their habitats.

Madagascar - Poster - WIOMSA Symposium 2022

Assessment of the Betsiboka estuary mangrove areas from 1989 to 2019

Ravaka RANDRIANATOANDRO (University of Antananarivo); Éric DELAITRE (IRD, UMR Espace-Dev); Samuel RAZANAKA (Centre National de Recherches sur l'Environnement); Dominique HERVE (IRD, UMR SENS)

The Betsiboka estuary mangrove, one of the most extensive mangroves in Madagascar, is of socio-economic and environmental value that justifies spatial monitoring.

The spatiotemporal dynamic of the geomorphological formation of the Betsiboka estuary and its colonization by the mangrove has been reconstituted between 1989 and 2019 on the basis of eight LANDSAT images taken during the dry season at low tide, in such a way as to capture as much as possible of the emerged area. From this, we have devised maps of the land cover with three classes: water, bare soil / salt-marsh / non-mangrove vegetation, and mangrove, a map of changes in the land cover (1989 to 2019) and maps assessing the extent of the mangrove areas (extension and loss). In addition, on the basis of these maps, twelve transects were positioned from upstream to downstream, the same distance apart, perpendicularly to the main axis of the river, and including the two banks. This cartographical system embedded in a GIS provides a basis for quantifying the specific dynamics of the three land cover classes for each transect.

Mozambique - poster WIOMSA symposium 2022

Modeling saltwater intrusion in Incomati River as a contribution to the determination of Dynamic Environmental Flow

Clemêncio Nhantumbo (Eduardo Mondlane Univ., Faculty of Engineering), Dinis Juízo (Eduardo Mondlane Univ., Faculty of Engineering), Vânia Saúl (Eduardo Mondlane Univ., Faculty of Engineering), Nordino Paluluane (Eduardo Mondlane Univ., Faculty of Engineering), Mary Shirima (Eduardo Mondlane Univ., Faculty of Engineering)

The aim of this study is to analyse saline intrusion in the Estuary of Incomati River as a contribution to sustain interdisciplinary discussions on environmental flows requirements in this part of the system.

Madagascar - Poster - WIOMSA Symposium 2022

Estimation of the concentration of suspended solids in the Betsiboka river using Sentinel 2 satellite images

 Hary-Riana Ranjalahy (CNRE, PhD student); Robison, Laurent. (CNRE); Rakotondraompiana, S.; Rasolamanana, E.

Betsiboka, one of the largest rivers in Madagascar, flows into the Mozambique Channel at Mahajanga. It is also the river with the highest sediment load from ferralitic soils and known worldwide for its red color waters. The suspended matter load has progressively increased, to the point of almost filling the upstream part of the estuary and modifying the geomorphology of the entire downstream part, with the appearance of numerous islets. The objective of this study is to estimate the suspended matter load that the river drains using Sentinel2 satellite images.

Comoros - Poster - WIOMSA Symposium 2022

How to manage marine biodiversity by integrating a Vague notion? Ecosystem services under the constraint of social representations and field realities in the Comoros

Nassim Said Abdallah (Univ. de la Réunion), Gilbert David (IRD, UMR Espace Dev)

The evaluation of ecosystem services (benefits offered to humans by ecosystems) is still mainly focused on the supply of services or their monetary value without explicitly studying their actual contribution to the well-being of inhabitants or users, except for links to health (Prévot and Geijendorffer, 2016). Our work aims goal to address these shortcomings by consist proposing to explicitly assess the perception that individuals have of the contribution of ecosystem services as a component of their well-being.

The methodology implemented is based on the evaluation of social representations by associating both structured interview, cognitive graph and cognitive map. 

Mozambique - Poster - WIOMSA Symposium 2022

A participatory observatory in Macaneta coastal wetland for the design of socio-environmental flows from the Incomati River (Mozambique)

Stéphanie Duvail (UMR PALOC, IRD), Dercio Alberto (Univ. Aix Marseille and IRD)

Environmental flows are a critical issue for Mozambique: it is a downstream country with most of the catchments of the highly seasonal rivers originating in upstream neighbouring countries. These transboundary rivers are regulated by storage dams and are subject to significant abstraction, mainly for irrigated sugar cane. Many of the upland grasslands have also been converted to plantations of exotic trees that have reduced runoff. Thus, Mozambique has witnessed a loss of net productivity in many of its estuaries and deltas as more dams became operational, reducing freshwater and sediment flows. This is what is happening for the coastal wetland of Macaneta, in the Marracuene District, Maputo Province, at the mouth of the Incomati River. The Piggs Peak Agreement of 1991 signed between South Africa, Eswatini and Mozambique established a minimum guaranteed cross border flow of 2 m3 s-1 while it was estimated at around 200 m3 s-1 in the 1950s.