Limnetica 32
Energetic aspects of spawning migrations and their implications for the management of southern European diadromous fish populations
Migratory species display very important roles in aquatic ecosystem functioning. The journeys between different habitats throughout the lifetime increase survival and reproductive success; however, a large energetic investment is required. Most diadromous fish species cease feeding soon before they start the spawning migration; thus, the energy available for maintenance, gonadal development and migratory journeys is limited. Diadromous species spend up to 90 % of the total energy available, and in some cases, the entire population dies during migration. The energy consumption during this phase is critical and affects the spawning and post-spawning success.
Several diadromous species are endangered due to the increase in human activities that have negative effects on aquatic habitats. The southern distribution range of most of the European diadromous species is the Iberian Peninsula. Several threats to diadromous species are present in this region, and extra energy consumption is required during spawning migration which compromises their conservation. Consequently, management measures for such species should consider their energetic limitations.
This review presents the energetic implications of diadromous spawning migrations and discusses the anthropogenic factors that negatively affect the spawning journeys of native southern European species. The spawning energetics of the diadromous species should be considered by natural resource managers; however, the integration of this domain still requires additional studies to measure the effects of the anthropogenic activities on these species.
