Overfishing and climate change in oceans: VUB biologists develop guidelines for protected areas

Overfishing and climate change in oceans: VUB biologists develop guidelines for protected areas

Area selection and citizen participation crucial for success

Overfishing of seas and oceans remains a major problem. One solution is to set up Marine Protected Areas (MPAs), where fishing is no longer allowed – but this doesn’t always take into account the organisms present or the impact on local fishing communities.


Dr Hajaniana A Ratsimbazafy and Professor Marc Kochzius of VUB’s Marine Biology Research Group have carried out a multidisciplinary study in which they combined historical, political, economic and demographic evaluations of the Madagascan coast with biological research into genetic diversity, population structure and connectivity. The result is a scientifically unique document that can help policymakers to select and manage an efficient network of protected areas around the island. The holistic approach can be useful elsewhere to address the problem of overfishing while ensuring the economic security of local populations whose living depends on fishing. Kochzius: “We are the research group that has done the most research on the connectivity of coral reefs and mangroves in East Africa worldwide. As a result, we today have a much better understanding of the connectivity of this region, which in turn can produce nature conservancy recommendations for these countries.”

Marine reserves are set up to maintain a habitat or populations at a specific location. Often too little attention is paid to careful biological research into the distribution pattern of the endangered species. However, this information is important for the successful establishment of MPA networks.


The marine biology research group at VUB, with the Institute of Marine Sciences of Madagascar, has carried out a study on the management of marine reserves in Madagascar. The island, a hotspot for biodiversity, is transforming ever larger parts of its territory into nature reserves, and aims to triple its current protected marine area by 2020. Dr Ratsimbazafy analysed five key species – the blue starfish, an octopus, a snail species and two shrimp species – to investigate genetic diversity, genetic population structure and connectivity between 18 possible MPAs along the coast of Madagascar using mitochondrial COI sequences and nuclear microsatellites. A survey of 18 experts from Madagascar was then added to this field study. 


Both studies emphasise that the current distribution of marine reserves does not cover all existing populations around the island. According to the researchers, it is therefore necessary to align the establishment of marine reserves with the capacity of the organisms to spread (i.e. to colonise other areas) in order to promote resistance to disturbed areas, but also to be able to better define the existing populations. Furthermore, in the area of marine reserve governance, efforts between stakeholders should be better coordinated and local communities should be given more responsibility. The integration of customary law into regulations for the conservation of the marine environment and sustainable management in Madagascar is also crucial.


The results of the governance analysis have already been published in the Marine Policy Journal this year. Two results from the population genetic studies have been published (in the Oxford Journal of Molluscan Studies in 2018 and in Plos One in 2019), and three other results are in preparation for publications.


“Preserving marine life is a major challenge. One of the main culprits is overfishing: fish consumption continues to rise and some 30% of fish products are fished unsustainably,” says Dr Ratsimbazafy. “If we want to be able to continue to consume fish and preserve marine life, there is definitely work to be done. In addition to consuming more sustainable fish, establishing reserves is certainly a good thing. But with global warming, there is another factor that is endangering fauna and flora.”






Dr. Haj A. Ratsimbazafy  (EN-FR)


+32 484 99 59 15


Prof Marc Kochzius (NL-EN-DE)


+32 470 26 49 78

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Dr. Haj A. Ratsimbazafy (ENG en FR)
Prof Marc Kochzius (NL, ENG en DU)
Dr. Haj A. Ratsimbazafy (ENG en FR)
Prof Marc Kochzius (NL, ENG en DU)
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