Chalk stream salmon, a genetically distinct population of Atlantic salmon native to England’s chalk rivers, are facing a sharp decline, raising concerns among conservationists and river advocates. These fish, sometimes referred to as England’s “white rhinos” due to their rarity, have seen their numbers dwindle to a level that threatens the viability of their populations.

The chalk stream salmon, proposed by scientists to be classified as a separate subspecies—Salmo salar calcarianus—are believed to be the genetic ancestors of all Atlantic salmon, having inhabited the first rivers that emerged after the last Ice Age. Annual returns of these fish to rivers such as the Itchen now number only in the hundreds. Recent data from 2024 estimates the spawning run on the River Itchen at around 182 salmon, a figure substantially below the threshold for a self-sustaining population.

The decline has been attributed to a combination of factors, including polluted waters, water abstraction, obstructed migration routes, and adverse conditions at sea. However, some threats to the salmon population along the Itchen may be more immediately addressable. For example, poaching along the river’s best spawning grounds presents a significant concern.

An encampment in the river’s wooded stretches near Southampton has been identified as a hotspot for illegal fishing activity. Reports from local riverkeepers indicate that poachers use nets to catch salmon, kill the fish, and sometimes publicly share videos of their catches, contributing further to the fishery’s decline. Estimates suggest that between 20 and 40 salmon may be taken illegally each year from this vulnerable population—amounting to up to 20% of the annual run.

Efforts to curtail poaching and protect the salmon have been hindered by bureaucratic delays and resource allocation issues. Southern Water allocated £1 million to fund specialist bailiffs dedicated to chalk stream conservation over a ten-year period, but the funds, managed by the Environment Agency, have yet to result in active enforcement. Concerns within the Department for Environment, Food and Rural Affairs regarding the optics of accepting money from a utility company have reportedly stalled deployment.

Local authorities have also been criticized for failing to take decisive action. The Environment Agency and local councils have not removed the encampment, installed signage to demarcate fishing rights, deployed surveillance cameras, or enacted temporary fishing bans on vulnerable stretches of the Itchen.

Advocates point out that addressing poaching through increased enforcement and community engagement could provide immediate relief to the struggling salmon population, even if it does not resolve all underlying environmental challenges. Meanwhile, the situation also highlights broader social issues, including homelessness, as some individuals living at the encampment cite lack of housing and the safety of the woodland location as reasons for their presence.

Conservationists emphasize that while the issues are complex, inaction could cost the chalk stream salmon their last strongholds. With their spawning season underway, the need for swift, coordinated measures to protect this fragile population grows ever more urgent.