Danube Sturgeons: Endangered Animals Spotlight

Sturgeons are an ancient migratory fish that have outlasted the dinosaurs. There are 27 sturgeon species inhabiting coastal waters, rivers and lakes of the northern hemisphere, and the Danube River (which flows through much of Central and Southeastern Europe, from the Black Forest into the Black Sea) preserves some of the most important sturgeon populations nowadays. 

KEYSTONE SPECIES

Danube sturgeons are arguably a keystone species, which are defined as species that are so important to a particular ecosystem, that their removal would cause drastic and harmful changes. Danube sturgeons play an important role in maintaining the balance and diversity of their environment, and their presence indicates a healthy ecosystem. This is because they are apex predators (at the top of the food chain), and so they are crucial in regulating the populations of their prey (such as fish and invertebrates).

Sturgeons also facilitate nutrient cycling in their habitat: they excrete waste products that can be used by other organisms in the ecosystem. Finally, their migration patterns bring nutrients from one part of the river to another, which has a significant impact on biodiversity around them. 

CRITICALLY ENDANGERED

Until the 19th century, giant sturgeons migrated up the Danube as far as Germany. They used to grow up to 4.5 metres long and live up to 100 years. The Danube river is home to several sturgeon species, such as the Beluga sturgeon, the Sterlet, and the Russian sturgeon. Unfortunately, today five out of the six species native to the Danube are listed as critically endangered. 

This is due to, on the one hand, their habitat being disrupted by pollution. On the other hand, poaching plays a big role as well: sturgeons are valued for their meat and eggs (also known as caviar), and the illegal trade of these is one of the main direct threats to their survival. In order to protect the sturgeons, several countries in the Danube region have implemented laws and regulations, which include restrictions on fishing gear and the establishment of protected areas, such as the Natura 2000. However, the enforcement of these laws can be difficult, particularly in areas going through economic hardship. Poachers use illegal nets and other methods to catch the fish, and often target the larger and older ones, which are most valuable for their caviar. 

Illegal sturgeon fishing had often been cited as significant threats to the sturgeon population, but until recently, substantiated data had not been available. In 2021, a WWF market survey provided evidence of the actual scale of poaching and illegal trade of meat and caviar from wild-caught sturgeon in the Lower Danube Region (Bulgaria, Romania, Serbia and Ukraine).  The survey had a unique methodology that combined official data on illegal fishing activities from the authorities, a market survey and forensic analysis. 

WILDLIFE FORENSICS

Forensics has been historically used on humans, but only recently has it started being used to investigate crimes against wildlife. Wildlife forensics is a crucial tool to protect endangered species and habitats, as it can help identify the species of origin of seized wildlife products, leading to the prosecution of poachers and traffickers. It also helps combat the illegal trade of animal and natural products, since it can disrupt criminal networks by identifying the source of illegal products and tracing them back to the people profiting from them; and it is useful in legal terms, as it can provide crucial evidence in legal cases in involving wildlife crimes, which will hopefully deter future criminal activity. Finally, wildlife forensics can also inform conservation policies. 

WILDLIFE FORENSIC FUND

With all of the above in mind, the Wildlife Forensic Fund mobilises knowledge, expertise, capacity and innovation to fight wildlife crime. We raise funds for research, organise seminars and grant scholarships to students and rangers so they can learn about wildlife forensics. We are also proud to be a consortium partner of the project Nature FIRST, which aims to tackle the decline of biodiversity in Europe and beyond. For now, they are focused on specific European field sites, one of which is the Danube Delta river, Europe’s largest remaining natural wetland. 

Having noticed that one of the biggest threats for the Danube region was the poaching of sturgeons (not only because they are a threatened species on their own, but also because of the impact they have on the environment around them), Nature FIRST is closely monitoring the area, and developing tools to protect both the sturgeons and their ecosystem. Only through a data-driven approach that mixes ecology sciences, environmental observations and forensics can the problem be properly tackled and a solution be found.