
Freshwater fish are often neglected by conservationists in favor of their brightly colored, more photogenic ocean relatives. But Cape Town-based biologist and photographer Jeremy Shelton bucks the trend, photographing fish like these Breede River redfins.

Focusing on freshwater fish is increasingly important, with as many as a third of global populations in danger of extinction and 80 species already extinct, according to a 2021 WWF report. A Cape galaxias is pictured here in the Sonderend River in the Western Cape of South Africa.

Survival of freshwater ecosystems is critical both for biodiversity and for people. They provide clean water for drinking, agriculture and sanitation. Pictured here is the Rondegat River, Cederberg, which was the site of an alien fish eradication program in 2012. Since then, biodiversity in the area has flourished.

This picture shows Clanwilliam sawfin -- found only in the country's Northern and Western Cape provinces -- swimming in the Driehoek River. South Africa's rivers are home to exceptional biodiversity, with half of its freshwater fish species found nowhere else in the world, according to the 2018 national biodiversity assessment.

However, freshwater fish are also the most threatened species group in South Africa and wetlands and rivers are under more pressure than any other ecosystem, the report says. Pictured here are red minnows in the Rondegat River.

According to the report, the main threats to freshwater fish populations are habitat degradation, climate change and predation by invasive alien fishes, such as the sharptooth catfish (pictured).

Pollution is another major threat to freshwater ecosystems, as is climate change and water extraction. Shelton wants to capture these threats in his images.

These dead fish are pictured in the Gouritz River, a dry part of the Western Cape. Shelton says that the fish were killed due to excessive water extraction and a harmful algal bloom.

But fish aren't the only subject of Shelton's photographs. Rivers and wetlands support a diversity of life, from amphibians like the Cape river frog (pictured), to river crabs, insects and water snakes.

Pictured here are critically endangered ghost frog tadpoles, found only in South Africa. The main threats to the species, according to the International Union for Conservation of Nature, are agriculture and aquaculture, human disturbance, water management and invasive non-native species.

The stonefly (pictured) acts as a healthy river indicator, explains Shelton. As one of the most sensitive invertebrates in South Africa, its presence indicates that the water quality is good and fit for human use. But if it disappears, it's a sign of pollution or some other disturbance, he says.

Shelton also likes to capture the moments of connection and curiosity between people and freshwater life. Shown here snorkelling with Cape kurper fish is Jordan Calder, a conservation biologist turned life sciences schoolteacher.