Climate Change and Fish Migration | Diades
When fish travel between rivers and the sea, they carry with them a story that reaches far beyond the waterline. A coalition of European organisations came together under the name Diades to research that story in depth, then share what they found. Chocolate Films was commissioned by the project to produce four films and an animation. The challenge: to translate five years of scientific fieldwork into vivid, watchable content.
Fish migration is about more than the movement of a single species. It connects freshwater ecosystems to the wider conversation about climate change, biodiversity, and the health of our natural world. Collaborating with Diades, our writers, directors, producers and editors worked closely alongside scientific experts to find the human story inside the data, and to tell it in a way that stays with the viewer.
A Genuinely International Project
Diades brought together more than 27 partner organisations across several European countries. The list includes the Office Français de la Biodiversité, the Irish Federation of Sea Anglers, and the Centre for Environmental and Aquaculture Studies. For Chocolate Films, a project at that scale is exactly the kind of challenge we welcome.
Working across so many partners means taking real care to understand the goals of each stakeholder before a single frame is shot. Our producers held regular weekly calls with the wider group. They conducted extensive research and built a shared understanding of what each partner needed the films to achieve. The result was a suite of short information films drawing together varied perspectives into one compelling body of work.
What made this project work was listening first. Our partners trusted us with research they have spent years developing. Our job was to serve that material with honesty and creativity in equal measure.
Making the Films Accessible
By its very nature, the project required content in multiple languages. This shaped our approach from the earliest stages of pre-production. At Chocolate Films, we feel that filming contributors in their own language helps protect the authenticity of what they share. It allows emotion, nuance and expertise to come through naturally.
That commitment meant sourcing filmmakers with the relevant language fluency. Our post-production team advised the client throughout on subtitling strategy and quality control. This ensured the final films were clear and accessible to audiences across all the partner territories.
On Location: The Story of Fish Migration
Over the course of the project, our filmmakers shot in some remarkable locations. These included Minho river in Portugal, the Guipuzcoan rivers and the river Ulla in Spain, the Gironde-Garonne, the Dordogne and the Normand-Breton Gulf in France, and the Tamar, Taff and Frome rivers here in the UK.
This was specialised fieldwork. Thorough risk assessment shaped every stage of travel and content collection. Producers planned shoots around weather conditions and the lunar cycle to place our filmmakers on riverbanks after dark. The crew captured small fishing boats using specialist lenses and drones from the shore.
Contingency planning of that depth is a craft in its own right, and one we take seriously. The Diades project showed what is possible when a production team with genuine environmental knowledge works alongside marine organisations, local fishing communities, and scientific partners, with mutual respect and a shared investment in the outcome.
Part of a Wider Commitment to Sustainability
Chocolate Films works extensively in the sustainability sector, and our own operations follow a sustainable production model built around the same values we bring to client work.
Diades sits alongside other long-term environmental partnerships we are proud to hold. For the Villars Institute, we produce expert interviews, event films and social content on an ongoing basis, giving them a consistent, high-quality platform to share their work and advance the case for a nature-positive future.
If you are working on a project in the environmental, sustainability or nature sectors and want to talk about how film can serve it, we would love to hear from you.
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