Making it easier for all countries to perform fish stock assessments

At a time when fish populations are threatened by overfishing, climate change and marine pollution, it is important for countries to know how much fish is left in their respective Exclusive Economic Zones and for researchers to conduct estimations on how the global ocean is faring in this regard.

Most mechanisms to assess the state of exploited fish populations, however, require fisheries scientists and managers to either use a large amount of wide-ranging fisheries data or expensive sampling equipment such as trawls, seines, acoustic and/or video surveys. But in most places, and particularly in developing countries, both extensive data and sophisticated sampling technology may be hard to come by.

This is where the MAVA-funded Learning and Sharing support received by the Sea Around Us comes in.

Based on the CMSY stock assessment methodology developed by Froese and colleagues in 2016 and which is particularly suited for data-limited situations, the Sea Around Us initiative created a series of four, ~6-minute animated videos that present the theoretical principles behind this computer-intensive method and offer a step-by-step guide on how to perform an assessment.

The target audience of these video tutorials includes fisheries managers, conservation NGOs and university students and researchers around the world but especially in developing countries, who are interested in understanding what happens, below water, when fisheries catches increase.

The idea is to show viewers how to estimate what would be the maximum sustainable yield (MSY) of a given fish/invertebrate species population by analysing fisheries catch time series from all sectors (industrial, artisanal, subsistence, recreational) in a given area over at least 10 years and if using the Sea Around Us data, up to 70 years.

By learning the CMSY methodology and learning how to perform assessments using it, users can get a detailed picture of how much fishing a stock can support in the long-term without depleting the biomass left in the ocean, provided that environmental conditions remain stable.

To increase the accessibility of the videos, not only were they made short but also in an animated format led by a scientist named Ola. They were also uploaded to YouTube, as the platform is light enough to work even with slow internet connections and is available in most countries. All videos were also voiced over in English and French and include subtitles in Spanish, Portuguese, Italian, Greek, Arabic, Chinese and Japanese.

In an initial dissemination phase, the videos were sent directly to over 1,500 people (researchers, students, fisheries organizations, and government organizations) from over 30 countries, with a special focus on African and Latin American countries. Now, the videos are freely available for all interested parties to access and learn the CMSY methodology.

The Sea Around Us has applied this method to over 2,500 fish and invertebrate populations exploited since the 1950s in the Exclusive Economic Zones of all maritime countries and the high seas. The overall results show sharp declines in popular seafood species across the world, with populations in the EEZs of countries such as Cape Verde, The Gambia, Guinea, Guinea-Bissau, Liberia, Mauritania, Senegal and Sierra Leone showing strong overexploitation rates.

Promoting the idea of in-country researchers, students and fisheries managers learning the CMSY methodology through the videos developed by the Sea Around Us and consequently performing their own stock assessments has the potential to inspire them to push for a redefinition of local policies and management mechanisms that do not lead to sustainable fisheries.

Read more on the Sea Around Us website here.

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