Alexandre Valente

Phylogeographical analysis reveals multiple conservation units in brook lampreys Lampetra planeri of Portuguese streams

The populations of brook lamprey Lampetra planeri of Portuguese Rivers were analysed phylogeographically using a fragment of 644 bp of the mitochondrial control region of 158 individuals from six populations. Samples representing L. planeri and migratory lampreys Lampetra fluviatilis of rivers draining to the North Sea and the Baltic Sea were also included to assess the relationships of Portuguese samples. The data support a clear differentiation of all the populations studied. Several populations, which are isolated among themselves and also from the migratory lampreys, proved to be entirely composed of private haplotypes, a finding that supports some time of independent evolutionary history for these populations. This, combined with the geographic confinement to small water bodies, justifies the recognition of at least four conservation units in the Portuguese rivers Sado, São Pedro, Nabão and Inha.

Evaluation of the water quality and biotic communities of two Portuguese reservoirs (Alto Lindoso and Ermal) and their relationship with recreational fishing

Alto Lindoso (Lima basin) and Ermal (Ave basin) dams (Fig. l) were built originally for the p_roduction of hydroelectricity but other uses of these reservoirs have evolved. These include recreational uses bathing, aquatic sports and angling. Al! these activities constitute potential pollution sources. Although anglers fish in both reservoirs, the Ermal Reservoir has higher angling pressure from a higher number of competition events than the Alto Lindoso Reservoir. The systematic use of baits poses potential risks for water quality, the established community and biological productivity.

Recreational fishery in Alto Lindoso reservoir (River Lima, north Portugal).

Abstract The presence of anglers in Alto Lindoso reservoir, at the Peneda Geres National Park, was noted during the entire fishing seasons of 1995 and 1996. Anglers presence was irregular, more intense on weekends and holidays, declining as the season progressed. Site choice was mainly determined by road accessibility. Inadequate fishing conditions, the poor and irregular catch results, and the changes in the fish community of the recent Alto Lindoso reservoir might be the causes for the observed decline of angler competition. Study of the fish community, based on angleris catch and gill net samples, revealed that the fish community was mainly formed by Iberian cyprinids. Angling appraisal and knowledge of the fish communities is needed before the development of a correct management strategy.

Biomanipulation of Furnas Lake, Azores: effects of repeated fish removal

Fumas Lake is a small mesoto eutrophic water body located in an ancient volcanic crater ofSiio Miguellsland Azores. In addition to agricultura( nutrient inputs, high densities of herbivorous fish (mainly common carp), as well as (irregular) hypolimnetic aeration contribute to maintain high levels of turbidity in the lake through resuspension of the nutrients accumulated in the sediment. ScHEFFER et al. ( 1993) suggested that turbidity in shallow lakes is not a smooth function of their nutrient status. Lakes are thought to have 2 distinct equilibria: a clear state dominated by macrophytes anda turbid state dominated by algae. A shift from turbid to clear water conditions is favoured by ( 1) reduction ofnutrient concentrations, reducing algal growth; (2) increased light availability, favouring vegetation, which retains sediments, protects zooplankton and consumes nutrients; and (3) reduction of planktivorous and benthos-feeding fish stock, reducing consumption of zooplankton, which grazes on phytoplankton, and reducing sediment resuspension with release of nutrients from the sediment pool (JEPPESEN et al. 2007). To improve water quality in the Fumas lake, a substantial part of the herbivorous and bottomfeeding (thus sediment resuspending) fish population, mainly common carp, was removed. Water quality was analysed in terms of turbidity, chlorophyll a, trophic state index values, macrophytes and zooplankton.