The Beluga Sturgeon is probably the most famous of all the sturgeon fish. They are ancient fish, that have graced our planet for millions of years.
Often referred to simply as the Beluga, the species is scientifically known as (Huso huso), and belongs to the ‘Huso‘ genus, which is one of the four genera of sturgeon within the ‘Acipenseridae‘ family. Along with the River Baluga – kaluga (Huso dauricus) – these are the only two species within the genus and there are no subspecies.
This ancient creature primarily calls the Caspian and Black Sea basins home, as well as some surrounding waterways and rivers, like the Danube. At one tome though, their range was much bigger, including the Sea of Azov and the Adriatic Sea.
As one of the largest bony fish species, the Beluga Sturgeon’s sheer size dwarves other fish in their fresh or brackish water homes. However, their existence is threatened, primarily due to the high demand for their roe, known as beluga caviar. This elitist delicacy has led to significant overfishing and poaching, pushing this magnificent species closer to the brink of extinction. And for what? a spoonful of fish eggs!
Appearance & Characteristics of Sturgeon
Juvenile beluga are tiny, only a few centimetres long, but as adults these long lived fish are massive. The older the fish, the larger they are and historically, examples have been recorded reaching a length of up to 23 feet (around 7 meters) and over 3,400 lbs (1,530 kg). It’s rare to find examples anywhere close to this today, as with overfishing, finding very old beluga is like finding a needle in a haystack. Of examples caught today, the average adult is closer usually between 5-11 feet, and no more than 600 lbs. If they are given the chance to thrive again, and to reach old age, they are capable of growing much bigger.
The beluga is sexually dimorphic with females growing up to around 20% larger than males. They have a distinctive elongated body, with a unique tail and a skin adorned with protective scutes. Their dorsal fin is soft and flexible, while their anal fin is shorter and more rigid.
As they age, their appearance undergoes a transformation. While juveniles possess a slender frame and a narrow head, adults become more robust, with a pronounced hump on their back. Their large, crescent-shaped mouth changes too, becoming even more prominent. This helps them to consume a variety of prey.
Like many sturgeon fish, the beluga has amazing electroreceptors that help them locate prey, and sensory barbels in front of their large mouths, that help them detect food on the seabed.
Distribution – Location and Habitat
The Beluga Sturgeon’s primary habitats are in Russia and Central Asia, particularly the Caspian and Black Seas, with occasional sightings in rivers like the Danube. There is also a small population that exists in the Mediterranean Sea. Historically, they also roamed the Adriatic Sea, the Sea of Azov, and the rivers that connect these vast water bodies.
They can exist in water of widely varying salinity. From freshwater rivers, to brackish water and saltwater seas. They prefer deeper waters but not too far from the coast. They migrate to shallower regions, and make their way up estuaries and rivers during spawning seasons.
The Lifestyle & Behaviour of Beluga Sturgeon
Beluga Sturgeons are fascinating creatures with intriguing behaviours. Being anadromous, they undertake long migrations from saltwater habitats to freshwater rivers to spawn. These journeys can be perilous, but the drive to reproduce ensures their continued migration.
They prefer clean, hard substrates for laying their eggs, ensuring the next generation has the best chance of survival. Their spawning frequency varies, with most individuals reproducing every four to seven years.
While beluga might be seen in groups during their migration to mating and spawning waters, they are otherwise relatively solitary. Especially as they get older. They are not usually aggressive by males may compete for the best spawning grounds, especially if locations are few and far between.
Diet & Nutrition of Beluga Sturgeon
The diet of the Beluga Sturgeon changes throughout their lives as they grow and mature into their adult forms, but they are always carnivorous by nature. As opportunistic feeders, they adjust their diet based on availability. While younger sturgeons feed on smaller invertebrates, adults consume prey larger in size and variety.
They consume large fish, molluscs, crustaceans, depending on the availability in their particular habitat. Beluga in different regions, eat different prey, but some of their favourites include mullet, flounder, herring, carp and roach. Their large, crescent-shaped mouths allow them to capture and consume many types of prey, ensuring they receive the necessary nutrients for growth and survival.
Predators & Threats to Beluga Sturgeon
While the Beluga Sturgeon’s size offers some protection against natural predators, they are not entirely safe. Larger fish and marine mammals can pose a threat to younger sturgeons, but even juveniles have some protection in the form of their scute like scales. There are no natural predators that regularly prey on beluga specifically, but birds of prey, sharks, and sea lions might occasionally target them, particularly younger fish that are smaller and easier to target.
The biggest threat by far to the beluga though, is humans and our demand for their eggs. Overfishing, driven by the demand for beluga caviar, is the number one reason for these fish facing catastrophic decline. The meat of the fish itself is not highly regarded, but the eggs are an elitist delicacy and the fish are exploited for these massively. Habitat destruction and pollution from industrial and commercial use of their waterways further compound the challenges they face.
Beluga Sturgeon Reproduction
Reproduction is a critical aspect of the Beluga Sturgeon’s life. They are anadromous, migrating to freshwater rivers to spawn. The choice of spawning ground is crucial, with preference given to clean, hard substrates. Some might make a journey over 1000km upstream to find suitable spawning ground.
LIke all sturgeons, beluga are oviparous, meaning they lay eggs. A single female can lay thousands, even millions, of eggs at once. The number of eggs laid varies, but they are sticky and adhere to the chosen substrate. However, not all of these eggs will be fertilized and only a fraction of these eggs survive to adulthood.
From the egg, they will hatch into larval fish, and then into fry. In their first year, they will grow to around 20 cm long, and when they get to this stage they will usually leave their nursing areas, back into the main, freshwater rivers or lakes with the rest of the population.
Males reach sexual maturity first, usually between 12-16 years old. Females take a few years longer, between 16-22 years old but even when they reach this, they require specific environmental conditions to be able to spawn their eggs. These conditions don’t happen every year, and most will only reproduce every 4 to 7 years.
Beluga caviar is a luxury that has been enjoyed for centuries. Extracted from the roe of the female Beluga Sturgeon, this delicacy is sought after for its rich, buttery flavor and large, pearl-like grains.
It is an elitist delicacy now, but for much of history it was considered to be ‘poor mans food’. When fishing the rivers of Russia and the surrounding territories, peasants would use everything. It wasn’t until the fish population started to become scarce in these rivers that the fish eggs became in demand, and it was the elite that could afford to buy them. The eggs went from the tables of paupers, to being reserved for royalty.
Today, its popularity, combined with the declining numbers of the Beluga Sturgeon, has made it one of the most expensive foods globally.
Lifespan of Beluga Sturgeon
Beluga Sturgeons are long-lived fish, with some individuals – anecdotally suggested to live for over a century. Today, most adult specimens caught are believed to reach around 50-60 years of age, but given the chance, they could certainly live longer. They don’t reach sexual maturity until between 12 and 22 years of age, and are large, ancient fish.
Population and Conservation
The current status of the Beluga Sturgeon is alarming. Classified as critically endangered by the IUCN, their numbers have seen a drastic decline over the years. Some populations, particularly the Adriatic, are considered to be ‘extinct in the wild’. They have been a victim of exploitation and overfishing for centuries, and a shameful example of where human desire trumps survival of species.
Conservation efforts are in place, with organizations like the World Wildlife Fund leading the way. Bans on beluga caviar imports and increased awareness are steps in the right direction, but despite these efforts, the caviar trade remains big business. In some respects, these efforts have simply served to inflate the price of caviar, rather than alter the behaviour.
Despite this, there are some success stories. Captive breeding programmes in Italy show promise at reintroducing beluga to areas where they are currently locally extinct. Efforts to repopulate by introducing fertilized eggs to existing populations in the Caspian also show promise, but its a fine balance trying to increase a population against the demand for their eggs.
5 Fun Beluga Sturgeon Facts for Kids
- The Beluga Sturgeon can grow up to 7 meters long, that’s like having a small car swim beside you!
- They’ve been on Earth for so long that they saw dinosaurs come and go.
- Some Beluga Sturgeons may be able to live for over a century – that’s like having a great-great-grandparent fish!
- They may travel hundreds of miles upstream, just to find the perfect spot to lay their eggs.
- Their eggs, known as caviar, are considered a luxury food item and can cost a small fortune!