The research of the FFishGUL is mainly focused on Iberian fish, integrating different scientific areas such as taxonomy/systematics, genetics, ecology, biogeography, evolution and conservation biology.

The Iberian Peninsula is a hotspot of aquatic biodiversity, including a large set of restricted endemic fish species, most of which are currently listed as highly endangered. Despite the widespread concern about the conservation of native fauna, several key questions about biodiversity patterns and processes remain unanswered. To address these issues, a variety of morphological, ecological, genetical and cytogenetical analyses have been undertook in the frame of several research projects and contracts, under a comparative scope.

Overall, the majority of the research projects conducted by FFishGUL in CBA facilities aim to accomplish the following three general objectives:
    i) to acquire basic knowledge on evolutionary processes responsible for generating and maintaining genetic diversity within and among populations. This is likely to stimulate the long term economic viability and social value of fish species in the complementary domains of recreational and commercial exploitation (fisheries) and biodiversity conservation;

    ii) to allow the training of highly qualified biologists, researchers and research professionals in areas of high priority for Portugal, namely fish biology, evolutionary genomics, molecular ecology and conservation;

    iii) to increase the public awareness of the usefulness of university research regarding the improvement of management and conservation practices of natural populations.

Inside the FFishGUL there are three sub-units which integrate the research in the distinct topics - ecology, genetics and cytogenetics:

Ecology sub-unit: addresses the patterns of species distribution, abundance and diversity at multiple hierarchical scales and the processes that generate them. Its main focus is on the variation in population life-history traits and demographic parameters, resource use and selection, assemblage structure and function, and dispersal pathways and boundary processes, across both undisturbed and impaired Mediterranean stream landscapes. This is expected to provide also the basis for the development of broad strategies for the conservation of individual species, the maintenance of community diversity and the protection of key landscape processes;

Genetic sub-unit: the members of this sub-unit are affiliated at FCUL and MB and have a large experience in studies on phylogeny, phylogeography, population genetics and in conservation genetics and management of endangered fish populations. The research group has been using mitochondrial and microsatellite markers and has been also developing sequencing and SNPs in nuclear genes. More recently, they started addressing new questions in landscape genetics and functional genomics, particularly in non-model organisms, relating evolution to ecology and development. They are also developing candidate genes for sex determination in fish and candidate genes with putative adaptive role. The study of these genes within natural populations will permit to understand their role in selective/adaptative changes and in the diversification of natural populations;

Cytogenetic sub-unit: mainly targeted on fish chromosome differentiation and evolution, using conventional and molecular techniques, and also on the role played by both hybridisation and genome multiplication on evolutionary processes. The existence of a well-established diploid-triploid-tetraploid complex in Iberian freshwaters (the hybridogenetic minnow Squalius alburnoides) increased our interest. In fact, recent molecular data suggest for these phenomena a much higher significant role than previously suspected, even in the genome evolution of some vertebrate groups; therefore the main goal will be to contribute to these important questions of evolutionary biology.

The Squalius alburnoides complex originated through interspecific hybridization: