Metapopulations and the Atlantic herring

Two opposing concepts of Atlantic herring, Clupea harengus L., population structure are critically reviewed with the objective of unifying these divergent views under the metapopulation concept. It is concluded that neither the discrete population concept nor the dynamic balance concept adequately explains all the data associated with herring population structure and dynamics, including meristic and morphometric measurements, life-history traits, homing, year-class twinning, and biochemical analyses. However, the available information does suggest that Atlantic herring population structure and dynamics are well described within the metapopulation concept. The example of sympatric seasonal-spawning populations is used to illustrate the strategy, opportunity and mechanism by which local population integrity and persistence are maintained within the adopted-migrant hypothesis. Local population integrity is maintained through behavioural isolation, i.e. repeat rather than natal homing to spawning areas, while local population persistence is ensured through the social transmission of migration patterns and spawning areas from adults to recruiting individuals.