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217 p., Over the past 10 years, Species Distribution Models have become commonplace in the studies of biogeography, conservation biology, ecology, and climate change. However, most studies applying SDMs mainly quantify species-environment relationships and usually omit functional roles of species, biotic interactions and resource-consumer dynamics. Within this context, this thesis aimed to advance in the understanding of how biotic and abiotic factors shape species distribution and abundance by using the community of top predators of the Bay of Biscay as case study. To address this overall objective, we carried out three different studies that aimed to answer the following specific research questions:- To identify the main environmental and biotic drivers of species co-occurrences within the top predators-prey community of the Bay of Biscay. - To understand how co-occurring top predators share the environmental and trophic niche.- To define the role that prey, climatic and oceanographic variables in driving the spatio-temporal patterns of a highly mobile top predator.- To determine the relative importance of biotic and environmental drivers explaining the abundance and distribution of top predators.By this means, this thesis intended to obtain a more comprehensive understanding of the drivers governing the assemblage of top predators and a better knowledge of ecosystem functioning of the BoB.

The Working Group on Marine Mammal Ecology met in 2022 to address five terms of reference. Under the first of these, ToR A, new information on cetacean and seal population abundance, distribution, population/stock structure, was reviewed, including information on vagrant ma-rine mammal species. This was done to ensure the recording of possible range changes in marine mammal species in the future. For cetaceans, an update is given for the different species, providing for a latest estimate for all species studies. In this report, particular attention is given to the updating of information from Canadian and US waters, and together with those countries, latest estimates for cetacean species are provided. For seals, latest monitoring results are given for harbour, grey and Baltic ringed seals. In addition, where possible, local long-term trends are illustrated for those species, based on earlier WGMME efforts to assemble these data into the WGMME seal database. For both spe-cies’ groups, a first account of vagrant species is provided

217 p., Over the past 10 years, Species Distribution Models have become commonplace in the studies of biogeography, conservation biology, ecology, and climate change. However, most studies applying SDMs mainly quantify species-environment relationships and usually omit functional roles of species, biotic interactions and resource-consumer dynamics. Within this context, this thesis aimed to advance in the understanding of how biotic and abiotic factors shape species distribution and abundance by using the community of top predators of the Bay of Biscay as case study. To address this overall objective, we carried out three different studies that aimed to answer the following specific research questions:- To identify the main environmental and biotic drivers of species co-occurrences within the top predators-prey community of the Bay of Biscay. - To understand how co-occurring top predators share the environmental and trophic niche.- To define the role that prey, climatic and oceanographic variables in driving the spatio-temporal patterns of a highly mobile top predator.- To determine the relative importance of biotic and environmental drivers explaining the abundance and distribution of top predators.By this means, this thesis intended to obtain a more comprehensive understanding of the drivers governing the assemblage of top predators and a better knowledge of ecosystem functioning of the BoB.