Two decades ago scientists deemed the round goby a dangerous Baltic Sea invader. Now they see a resource: trials for human food, pet food and uses in fertilizer and feed.
The round goby is a small fish from the perch order and the goby family. It originates from the Black and Caspian Sea region and spread to the Baltic Sea through ships’ ballast water. It was first discovered near Gdansk in 1990 and in Estonia’s Pärnu Bay in 2002.
“At first, there were only a few, but ten years later the population was already noticeable and by 2012 the catch had reached a ton,” food scientist Rain Kuldjärv recalled on Vikerraadio’s “Huvitaja” program.
Since then, catch volumes have increased and last year alone nearly 700 tons of round goby were caught in Estonia. For fishermen, it has proven to be a profitable catch, while for scientists the challenge lies in how to add value to this invasive species.
Small fish with a big head
The round goby typically measures 15–20 centimeters in length, with its head making up a large part of its body. “That means it yields little fillet and nearly half the fish is lost during cleaning,” explained Kuldjärv. At the same time, its meat is tasty and very low in fat — just up to 1 percent. This makes it valuable for both healthy diets and pet food.
Because large amounts of waste must be processed, scientists have studied ways to use the head and innards as well. Fertilizer and animal feed production have emerged as potential options.
Research on ways to add value to the round goby has been ongoing in Estonia for several years. Scientists are also taking part in an international project to develop new products, with Kuldjärv’s team focusing on pet food.
“We’ve tested biscuits in which 70–80 percent of the ingredients are round goby. We add a little cranberry and pea protein to improve the texture,” he said. They are also making freeze-dried snacks and low-temperature dried treats.
Although the round goby is unfamiliar to Estonian consumers, it has already been offered in restaurants and even smoked in consumer trials. “Surprisingly, people rated smoked round goby higher than smoked sprat — for both taste and smell. Its appearance, however, was a drawback,” Kuldjärv said.
In cutlets, the fish stood out for its light, white and juicy meat, giving a more appealing result compared to sprat. “It’s also good in soups and pan-fried. Only our fermentation test, where we tried to imitate spiced sprat, failed. The flavor just didn’t come through,” the scientist noted.
According to Kuldjärv, the round goby is becoming an ordinary fish in Estonian waters. He believes it is no longer something to fear but rather to use creatively. “In fact, the round goby is already part of our everyday life. It hasn’t displaced sprat or Baltic herring, but it can offer new opportunities both in the kitchen and in industry,” he said.
—