Phase I- Ecological Economics of Mangrove-Associated Fisheries – Food Security and Sustainability

This project envisaged three main goals: to develop a conceptual framework for economic valuation of mangrove-associated fisheries, to analyse the ecological economics of mangrove mud crab fisheries at Incomati River and to integrate needs of the local community to conservation of mangrove resources – case study at Ungwana bay, Kenya. The study aimed to benefit both national micro (local communities) and macro economies, ensuring food security and the scientific community at large. The project was implemented at Ungwana bay, Gazi bay, Kipini mangroves, Ngomeni and Mto Tana in Kenya and at Incomati estuary, North East of Maputo bay, Mozambique.

A number of activities were carried out at Incomati during the project; i. Assessment of mangrove vegetation diversity, deforestation, forest structure, mangrove area variability and human pressure using a combination of remote sensing, GPS and ground-truthing, ii. Assessment of the seasonality, population abundance, size structure and diet characteristics of mud crab Scylla serrata using box trap and burrow excavation methods, iii. Assessment of charcoal production from mangrove forests through interviews. In order to assess the biology and trade of mud crab (Scylla serrata), some biological parameters (Carapace composition and estimate the fresh medium weight, sex and maturity), fishing effort (number of fishermen involved and catch) and monetary yields were estimated, iv. Also the anthropogenic transformation of mangroves and mud crab fisheries was studied.

The structure and regeneration of the mangrove forests in Ungwana bay were studied along belt transects in Kipini, Mto Tana and Ngomeni with aid of medium scale panchromatic aerial photographs. Effects of mangrove habitat degradation on fish abundance and diversity in Ungwana bay were also determined. Socio-economics of the fisher communities in the mangrove areas of Malindi-Ungwana bay was assessed using both secondary and primary cross-sectional data.

At Gazi Bay, Kenya, the following studies were done: comparative study of shrimps and epibionts abundance and diversity among natural, degraded and replanted mangroves was done, using stake nets and wood frames respectively; and return of ecosystem goods and services in replanted mangroves.

The main project output was research documents. Twelve research documents focusing on mangrove deforestation versus mud crab, woodcutters vulnerability and market surveys of Scylla serrata (mud-crab) in Mozambique, Structure and regeneration status of mangrove forests in Kenya, Estimations of above-ground biomass of mangroves and mangrove fisheries in Ungwana bay, Demonstration of extensive mangrove deforestation at Incomati estuary and how mangrove deforestation leads to mud-crab depletion and development of allometric equations for estimating above-ground biomass for mangroves in Kenya.

Some of the project’s outputs have a significant contribution to management, and decision-making processes at national, regional or global levels as explained below. Information on the direct relationship between mangrove deforestation and mub-crab availability; Mangrove deforestation and need for mangrove re-plantation in heavily deforested areas of Incomati estuary in Maputo. Identification of need for management plan of mangroves in peri-urban areas of Maputo and Beira in Mozambique; Identification of the role of stand tables for mangrove forests of Ungwana bay, Kenya, which will aid in the development of sustainable mangrove management plans; Allometric equations developed in this project will be useful in determining standing biomass of mangroves in Kenya and serve as a resource tool for the Forest department, mangrove conservation bodies and research institutions in Kenya. Knowledge on the mangrove fishery of Ungwana bay will help in sensitizing the need to conserve mangrove ecosystem and steer the vital need of local communities’ participation for sustainable mangrove conservation.

The project spinned off two projects: the PUMPSEA “peri-urban mangrove forests as filters and potential phytoremediators of domestic sewage in East africa” project and the TRANSMAP “Transboundary networks of marine protected areas for integrated conservation and sustainable development:  biophysical, socio-economic and governance assessment in East Africa”, project

For future studies along the project area, WIOMSA should focus on mangrove forestation trials, alternative livelihoods for people who were dependent on destroyed mangroves and the relationships between mangrove deforestation and fisheries. Description of mangrove status and management in all WIO countries and allometrics for mangrove species may also be considered.