Seasonal patterns in round goby (Neogobius melanostromus) catch rates, catch composition, and dietary quality

Abstract The round goby (Neogobius melanostomus; Pallas, 1814) is one of the most widespread invasive fish species. It originates from the Black Sea and the Sea of Azov but has un-intentionally been introduced to fresh and brackish water bodies on both sides of the Atlantic. Small-scale fishermen catch large amounts of the invasive round goby as the species continues to spread and populate new areas of the Baltic Sea. We were concerned with the possibilities for a “use and reduce” solution to the round goby invasion. However, to capture the interest of restaurants, supermarkets, and distributers, more information about seasonality in product supply and nutritional quality is needed. We therefore studied a round goby bycatch fishery in the Western Baltic Sea (Denmark) and describe the seasonal dynamics in catch rates, size distribution, condition factor, lipid and protein content, fatty acid profile, and meat texture. We found that while the catch rates peaked in spring, lipid content and meat texture improved significantly, later in the year. Protein content also peaked in late summer and fall, but it was only marginally higher compared to spring. We compare the results to relevant species and conclude that round goby is a relatively lean fish all year (only slightly fatter than for example cod). The firmness of the meat in fall, resembles farmed trout and it has a highly favorable fatty acid composition, reflected by a low n-6 to n-3 ratio. The main bottleneck related to the introduction of round goby to the consumer market is likely going to be the small size.