New evidence of alternative migration patterns for two Mediterranean potamodromous species.

Iberian barbel (Luciobarbus bocagei Steindachner, 1864) and Iberian nase (Pseudochondrostoma polylepis Steindachner, 1864) are two Mediterranean potamodromous fish species known to perform annual upstream migrations to reach spring spawning grounds. In the Mondego River basin, at the Coimbra dam, migratory movement patterns and individual size structure were assessed through a video recording monitoring system installed on an upstream section of a vertical-slot fish pass. Visual census for these target species during two consecutive annual cycles (2013-2014) revealed alternative migratory patterns, with the first peak of upstream movements in autumn, for both barbel (October-November) and nase (November-December).

Acoustic fish community in the Madeira Archipelago (North Atlantic Ocean): Characterization of sound diversity and daily patterns.

Marine ecosystems are increasingly subjected to anthropogenic pressures, which demands urgent monitoring plans. Understanding soundscapes can offer unique insights into the ocean status providing important information and revealing different sounds and their sources. Fishes can be prominent soundscape contributors, making passive acoustic monitoring (PAM) a potential tool to detect the presence of vocal fish species and to monitor changes in biodiversity.

Do catadromous thinlip grey mullet benefit from shifting to freshwater? A perspective from fatty acid signature analysis.

To investigate the potential benefits of the catadromous thinlip grey mullet (Chelon ramada Risso, 1827) migration to freshwater, the total lipid content and fatty acid (FA) profile of female's muscle and gonads caught in both the estuary and river were analyzed. The freshwater contingent presented a higher body condition, greater muscle gross energy, and larger gonads with higher lipid reserves. These animals showed a muscle profile rich in C16:1n-7 and lower LC-PUFA that contrast with the higher relative amount of C18:1n-9, n-3 FA, and unsaturated LC-PUFA, such as C18 and C20 FA found in the estuarine contingent.

Not so much a sea bass: Divergent European sea bass (Dicentrarchus labrax L.) freshwater incursions.

European sea bass (Dicentrarchus labrax [Linnaeus, 1758]) is a euryhaline marine migrant fish highly valuable for fisheries and aquaculture. Although juveniles are known to use estuaries and occasionally move to freshwater environments, these freshwater incursions had not been reported for adults. Recently, this behavior was observed in the Tagus River (Portugal) for adults occurring up to 150 km from the river mouth, about 80 km upstream from the tidal influence, suggesting the existence of a freshwater contingent.

Seascape genomics reveals limited dispersal and suggests spatially varying selection among European populations of sea lamprey ().

Sea lamprey is an anadromous and semelparous fish without homing behaviors. Despite being a freshwater, free-living organism for a large part of their life cycle, its adulthood is spent as a parasite of marine vertebrates. In their native European range, while it is well-established that sea lampreys comprise a single nearly-panmictic population, few studies have further explored the evolutionary history of natural populations.