Found in our rivers, canals, lakes and reservoirs, the eel is the only European fish to leave European rivers to spawn in the sea. It undertakes one of the most extraordinary journeys seen in nature. The eel was once abundant around the UK but is now critically endangered with numbers having declined by up to 95% in recent decades. © Tim Watts
Perhaps one of our most well-known UK fish, recognisable by the distinctive black spots on its side, the Atlantic salmon hatches in freshwater, migrates to the sea and then returns to freshwater to spawn. Numbers returning to spawn in UK rivers have dropped by over 40% © wild wonders of Europe/WWF
Sturgeons can be found in China’s Yangtze River, and are one of the four indicator species WWF monitors as a sign of the river’s overall health. The fish spawn in freshwater and then migrate out to sea to develop, returning to the river to propagate throughout their lifetime. Hydropower dams and other infrastructure that blocks their upstream migration present major threats. © WWF
The Mekong River, flowing through Lao PDR, Thailand, China, Cambodia, Vietnam and Myanmar, is home to the iconic Mekong giant catfish, one of the world’s largest freshwater fish (nearly 3m long). Though once common in the Mekong, rapid population declines have made the giant catfish into ghosts in the river. Among other things, dams are a big threat, because they block migration routes and isolate some populations. © WWF
The golden mahseer, often referred to as the tiger among fish because of its colour and name, can be found in India’s Ganga River. This beautiful fish can grow up to nine feet long and weigh 120 pounds. The mahseer’s lifecycle is complicated, and intimately related to how much water is in the river. It travels upstream during the monsoon to spawn and so depends on the river being unobstructed and free-flowing. © WWF
On 21 May, individuals, communities and projects from around the world will come together and take part in a global initiative to create awareness about the importance of free-flowing, unobstructed rivers for migratory fish.
Fish – such as Atlantic salmon, European eel and sea lamprey – need to travel up and down rivers, as well as between rivers and the sea, to reach spawning and feeding grounds or to find safe areas in times of drought or flood. However, many of these species are in real trouble because of man-made obstacles like dams, weirs and sluices, which create barriers in the river that fish can’t navigate and prevent them from completing their essential journeys.
Migratory fish face challenges in the UK but also throughout the world. Many of the world’s greatest rivers are home to migratory fish, for example the Mekong’s giant catfish, the Yangtze’s sturgeon and the Ganga’s golden mahseer.
There’s a handy directory on the World Fish Migration Day website listing a whole host of events across the UK and further afield. Through our projects like the HSBC Water Programme and WaterLIFE, we’re supporting occasions like this as part of our efforts to excite local communities and groups, and help them get more involved in improving the health of our rivers. You can find out more about what we’re doing by visiting the WaterLIFE website and the WaterHub.
I thought it would be nice to mark the day by celebrating some of the amazing migratory species that live here in the UK and around the world. Enjoy!