Atlantic herring demonstrate a remarkable tendency to return to their birthplace for spawning, similar to the patterns observed in migratory birds, sea turtles, and salmon. A recent study published in the journal Science Advances highlights this behavior among herring in the Baltic Sea.
Led by Dr. Dorothee Moll from the Thünen Institute of Baltic Sea Fisheries in Rostock, the research team provided the first definitive evidence of this phenomenon known as natal homing. Their investigation showed that these fish are likely to spawn in the same bays, lagoons, and estuaries where they were originally hatched.
The researchers utilized the chemical “fingerprint” from the otoliths, or ear stones, of the fish, combined with genetic analyses, to trace the origin and migratory patterns of the herring. Findings indicated that between 56% and 73% of the herring returned to their natal areas for reproduction, regardless of the size of the spawning region.
“This is the first evidence of pronounced spawning site fidelity in herring,” stated Dr. Moll, who is the lead author of the study. Previously, it was believed that younger, inexperienced herring would simply follow older fish to established spawning grounds, thereby learning the migration routes. However, this new research suggests that the various spawning locations along the coastline are not interchangeable.
Dr. Moll emphasized the significance of these findings for coastal zone management, underscoring the need to protect local spawning habitats to maintain the productivity and resilience of marine ecosystems. The Thünen Institute of Baltic Sea Fisheries has been examining the population dynamics of herring for several years, and this study builds on research conducted in 1997.
Earlier theories proposed that herring shoals might include “strays” during their extensive migrations between feeding and spawning grounds, which could facilitate genetic exchange among subpopulations. The current research allows Dr. Moll and her team to test this hypothesis and assess the proportion of returning herring versus strays.
Given the increasing human impact on coastal ecosystems, these findings are crucial. They highlight the close relationship between fish population productivity and the conservation of local spawning grounds, reinforcing the importance of habitat protection efforts.
For more details, refer to the study by Dorothee Moll et al, titled “Direct evidence of natal homing in an Atlantic herring metapopulation,” published in Science Advances.
