Evaluating blue fish alternatives to European sardines: Physiological condition, reproductive state and market potential of horse mackerel, mackerel and round sardinella

The European sardine ( Sardina pilchardus ) faces several challenges, such as the need to regulate fishing pressure to ensure the long-term sustainability of the resource. Its decline highlights the need to consider alternative blue fish, which can help diversify consumer choices. In an effort to identify alternative fish species, the current study examined the physiologic conditions, reproductive states and fat contents of sardines and three other blue fish species throughout the complete annual cycle. These species include the Atlantic horse mackerel ( Trachurus trachurus ), the Atlantic mackerel ( Scomber scombrus ), and the round sardinella ( Sardinella aurita ). The extensive sampling effort, which was conducted at nearly monthly intervals, yielded a total of 5,358 individuals across the four species. Atlantic horse mackerel exhibited high reproductive success, rapid postspawning recovery, and favourable muscle fat content and has emerged as a strong candidate for complementing or replacing sardines in the market during closures or fishing bans. Although the Atlantic mackerel is a promising candidate, the poor physiological condition of captured specimens indicates that its populations may be under considerable stress. As such, we cannot currently recommend this species as a sustainable resource but emphasize the need for continued monitoring. The low fatty acid levels in the round sardinella limit its potential as a direct replacement for sardines. However, given its favourable characteristics, such as low parasite counts and low mercury levels, it could be considered an alternative to sardines. Our results highlight the importance of constantly reviewing the knowledge and status of commercially exploited fish populations.