
Sunset (yellow) moon wrasse. Photo by John Turnbull, Flickr.
Fish can look “bigger on average” even while they are actually shrinking due to warming waters caused by climate change.
Aquatic animals that breathe through gills — including most fish and many invertebrates — are the backbone of life in oceans, lakes and rivers. They support biodiversity, shape food webs and sustain fisheries that feed millions of people worldwide. Understanding how these animals grow, reproduce and survive is therefore essential to understanding how aquatic ecosystems work — and how they continue to support human societies.
Labour and human rights abuses, overfishing, unreported, unregulated and illegal fishing, all spurred by subsidies provided to distant-water fishing fleets, are some of the most pervasive practices linked to the global seafood industry.
Witnessing and reporting on all of this are fisheries observers. Often scientists – marine biologists or ecologists –, fisheries observers are tasked by national frameworks, regional bodies, or international fisheries organizations with gathering information that supports sustainable fisheries management. Some are hired by the fishing companies they monitor.

Helostoma temminckii or kissing gourami. Image by Jörn, Wikimedia Commons.

Daniel Pauly at the DocumenTerre Film Festival in Montignac-Lascaux , November 2025. Photo by DocumenTerre.
The 16th edition of the DocumenTerre Film Festival, which takes place on an annual basis in Montignac-Lascaux in southwestern France, had, this year, a special focus on the oceans.