Maite Louzao

AZTI · Marine Research Division

Seabirds are one of the most threatened groups of marine fauna and are therefore good indicators of long-term and large-scale changes in marine ecosystems. Each year, numerous seabirds are admitted to Wildlife Rehabilitation Centers (WRCs), which play a crucial role in rehabilitating sick and injured individuals before releasing them back into thei...

The structure and functioning of ecosystems are largely determined by the interactions between species within a biological community. Among these interactions, species exhibiting similar vertical and spatial prey preferences can be identified, thereby belonging to the same trophic guild. Our study explored some trophic characteristics of a diverse...

In trawl-acoustic methods, machine learning can objectively assign species composition to echo-traces, providing a reproducible approach for improving biomass assessments and the study of schooling behaviour. However, the automatic classification of schools in multispecies environments is challenging due to the difficulty of obtaining ground truth...

The conservation and management of marine ecosystems hinge on a comprehensive understanding of the status and trends of top predators. This review delves into the ecological significance of marine top predators, examining their roles in maintaining ecosystem stability and functioning through an integrated analysis of current scientific literature....

Effective and sustainable management of small-scale fisheries (SSF) is challenging. We describe a novel approach to identify important fishing grounds for SSF, by implementing a habitat modelling approach, using environmental predictors and Automatic Identification System (AIS)-B data coupled with logbook and First Sales Notes data, within the SE B...

In the north-western Mediterranean there are two breeding species of procellariforms from the Procellariidae family: Scopoli’s shearwater Calonectris diomedea and the Balearic shearwater Puffinus mauretanicus. Long-term monitoring carried out in a number of breeding colonies provides enough data to be able to assess the conservation status of both...

How individual animals respond to climate change is key to whether populations will persist or go extinct. Yet, few studies investigate how changes in individual behavior underpin these population-level phenomena. Shifts in the distributions of migratory animals can occur through adaptation in migratory behaviors, but there is little understanding...

Estimates of population abundance are required to study the impacts of human activities on populations and assess their conservation status. Despite considerable effort to improve data collection, uncertainty around estimates of cetacean densities can remain large. A fundamental concept underlying distance sampling is the detection function. Here w...

Seasonal variations in hydrodynamic conditions play a critical role in prey availability at the base of the food web and thus have implications for trophic interactions at higher trophic levels. Here we use the combination of stomach content analysis (SCA) and stable isotope analysis (SIA) to investigate predator-prey interactions and trophic struc...

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are h...

The main goal of this paper is to improve the understanding of the spatial distribution of small-scale inshore fisheries (SSF) in coastal waters of the Bay of Biscay. The study used a participatory process, in which fishers, regional administration, and researchers were involved in supplying the data. Displayed on a 1-km2 grid, the data for effort...

Several bird species benefit from anthropogenic food subsidies, such as landfills and fishing discards, that are being reduced owing to introduced legislation. For instance, since 2019, Europe has passed legislation to reduce dramatically the amount of fisheries discards through the Landing Obligation (LO), which states that all fish species under...

In the context of trawl-acoustic surveys, the traditional method of integration per layer involves assigning the nearest and most similar species catch proportion to all echo-traces within a given layer. However, when the trawl catch composition is multi-specific, it becomes difficult to determine the individual school composition, and it remains u...

Fishery bycatch is a serious threat to several protected, endangered, and threatened species (PETs), requiring urgent action to develop and implement conservation measures. This study performs an Ecological Risk Assessment for the Effects of Fishing (ERAEF) using a spatially and temporally Productivity–Susceptibility Analysis (PSA) to calculate the...

Understanding the linkages within complex and evolving marine food webs is essential to comprehend marine ecosystem structure and dynamics. Carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope signatures are recognized to be powerful descriptors of the trophic ecology and trophic relationships within marine communities. Apex predators such as seabirds...

The use of Species Distribution Models (SDMs) has increased considerably in recent decades, notably for conservation purposes. SDMs are used particularly to characterise and predict marine top predator distributions thanks to the use of surface dynamic environmental variables (easily accessible and available at various spatial and temporal scales)...

Species Distribution Models are commonly used with surface dynamic environmental variables as proxies for prey distribution to characterise marine top predator habitats. For oceanic species that spend lot of time at depth, surface variables might not be relevant to predict deep-dwelling prey distributions. We hypothesised that descriptors of deep-w...

Species Distribution Models are commonly used with surface dynamic environmental variables as proxies for prey distribution to characterise marine top predator habitats. For oceanic species that spend lot of time at depth, surface variables might not be relevant to predict deep-dwelling prey distributions. We hypothesised that descriptors of deep-w...

In the Bay of Biscay, regional monitoring programmes and data on abundance and distribution of floating marine litter are scarce, contrary to many other European marine regions. Here, a joint analysis of multiyear observations (2017–2019) of floating micro and macrolitter and oceanographic conditions was conducted for the Bay of Biscay by combining...

Marine mammals have been proposed as ecosystem sentinels due to their conspicuous nature, wide ranging distribution, and capacity to respond to changes in ecosystem structure and functioning. In southern European Atlantic waters, their response to climate variability has been little explored, partly because of the inherent difficulty of investigati...

Characterizing the structure and functioning of marine ecosystems requires a deep understanding of the dynamics of its populations and the biotic interactions among them. To this end, we developed a mass-balanced food-web model of a regional sea in the Northeast Atlantic, the Bay of Biscay (BoB), considering one of the most important anthropogenic...

In habitat modelling, environmental variables are assumed to be proxies of lower trophic levels distribution and by extension, of marine top predator distributions. More proximal variables, such as potential prey fields, could refine relationships between top predator distributions and their environment. In situ data on prey distributions are not a...

Ecosystem-based fishery management (EBFM) is based on a holistic approach, recognising all the interactions within an ecosystem rather than considering single species or issues in isolation. Studies of catch profiles of target and bycatch species for different fleets and metiers are necessary for successful management of target species. Such studie...

Increasing human activities have detrimental consequences on marine ecosystems and their impact can have cumulative effects. Within marine ecosystems, seabirds respond to ecosystem variability and face multiple human pressures, especially threatened species. In long-lived species, juveniles and immatures could represent up to 50% of the total popul...

Aim Understanding the mechanisms that allow the coexistence of species is key to preserve full ecosystem functioning. In dynamic environments, the study of ecological niches faces the complexity associated to the three dimensionality of the habitat and requires information that reflects such heterogeneity. Within this context, this study intends to...

Foraging distribution of flying seabirds is constrained by environmental factors influencing individual decision-making. This must be particularly true during the breeding period, when individuals face additional limitations imposed by their central-place foraging behaviour. We used GPS data loggers and Argos PTTs to track the foraging flights of B...

Gelatinous zooplankton (GZ) have long been regarded as organisms taking over perturbed systems (e.g. competing with fisheries and damaging aquaculture), but more detailed studies are required in order to better understand their role in marine ecosystem functioning. The present study characterised the GZ in the Bay of Biscay (BoB), (1) determining b...

Protected areas (PAs) are increasingly being used world‐wide for the conservation and management of wildlife. Systematic conservation planning (SCP) aims at ensuring biodiversity persistence while minimizing the threats faced by the species and/or the economic costs related to protection. To account for spatio‐temporal interactions between species...

Effective conservation and management measures are needed to face the unprecedented changes that marine ecosystems, and particularly marine megafauna, are suffering. These measures require the identification of high-value biodiversity areas (HVBAs) which in turn require the identification of the essential ocean variables (EOVs) that shape the envir...

To develop an ecosystem-based approach to fisheries management a holistic perspective is necessary that goes beyond target species management, to preserve ecosystem functioning and, therefore, secure future food availability. To achieve these objectives, current fishery data collection programmes should widen their objectives to include the collect...

In marine ecosystems, seabird populations are well monitored, thus allowing their use as indicators of system fluctuations at multiple spatio-temporal scales. Population abundance estimates are essential features of any conservation and management measures and initiatives. Population abundances can be used to delineate the distribution range and fo...

Competition between closely related species that exploit similar niches is expected to lead spatial divergence or exclusion. However, in some cases, coexistence can be possible through the partition of resources. In the Bay of Biscay, where a rich community of small pelagic fishes is found, five species of specialist pelagic birds cooccur during th...

Distribution maps of cetaceans and seabirds at basin and monthly scales are needed for conservation and marine management. These are usually created from standardized and systematic aerial and vessel surveys, with recorded animal densities interpolated across study areas. However, distribution maps at basin and monthly scales have previously not be...

Identifying the role that environmental factors and biotic interactions play in species distribution can be essential to better understand and predict how ecosystems will respond to changing environmental conditions. This study aimed at disentangling the assemblage of the pelagic predator-prey community by identifying interspecific associations and...

Seabirds have been widely used to monitor marine debris by the analysis of plastic ingestion. With the aim of obtaining the first data on ingestion of plastics by different seabird species in the Bay of Biscay and evaluating their suitability as biomonitors of plastic pollution in this area, a total of 159 seabirds of fifteen species were analyzed....

The marine environment faces an increasing number of threats, mainly driven by anthropogenic activities, that are causing growing impacts on marine species and processes. In Europe, the EU Marine Strategy Framework Directive (MSFD) aims to achieve or maintain Good Environmental Status (GES) of the European waters by 2020. The Directive specifically...

In the last few decades, there has been a remarkable development of niche models to help understand the ecological response of species to current rapid environmental changes. In the present study, we applied niche modelling to the megafauna community of shelf waters of the northwestern (NW) and northern Iberian Peninsula in order to analyse the coe...

Marine predators move through the seascape searching for foraging resources. Prey configuration and oceanographic processes could therefore shape their 3-dimensional (3D) oceanographic habitats. Taking advantage of multidisciplinary oceanographic JUVENA surveys targeting biomass estimation of pelagic fishes, observations of 2 highly migratory pelag...

Marine litter is identified as the major ocean pollution today, with a significant impact on the environment. The transport of litter by ocean circulation is still poorly understood, and the management of marine litter remains a major challenge for local authorities. This work investigates the transport of floating marine litter (FML) in the coasta...

Changing environmental conditions can have non-linear effects from populations to ecosystems, which could increase following the strengthening of human activities. Investigating the potential role of threshold responses to increasing extreme events could help elucidate the mechanisms conferring resilience to populations and ecosystems, since extrem...

Shearwaters and petrels (hereafter petrels) are highly adapted seabirds that occur across all the world’s oceans. Petrels are a threatened seabird group comprising 124 species. They have bet-hedging life histories typified by extended chick rearing periods, low fecundity, high adult survival, strong philopatry, monogamy and long-term mate fidelity...

Trophic cascades and amplification throughout bottom-up processes make marine prey-predators particularly vulnerable to synergistic effects of exploitation and climate change. Understanding the species interactions in marine ecological networks is hence key for biodiversity conservation and sustainable management of exploited species. The present s...

Aim During their migration, highly mobile species cross multiple jurisdictional boundaries and multiple not‐specific marine protected areas (MPAs). When identifying the critical habitats where individuals aggregate, these areas can be ideal candidates for MPAs. This study was focused on the endangered fin whale (Balaenoptera physalus) for which the...

Aim Deep‐diving cetaceans are oceanic species exposed to multiple anthropogenic pressures including high intensity underwater noise, and knowledge of their distribution is crucial to manage their conservation. Due to intrinsic low densities, wide distribution ranges and limited presence at the sea surface, these species are rarely sighted. Pooling...

Estudios recientes sugieren que los depredadores marinos, y en especial las aves marinas, dependen sustancialmente de la presencia de otros depredadores para localizar el alimento. Este tipo de asociaciones interespecíficas también han sido ampliamente descritas entre los cetáceos, donde grupos mixtos de delfínidos han sido frecuentemente observado...

Capsule: Northern Gannet Morus bassanus counts obtained from a coastal monitoring network in northern Spain were highly determined by wind conditions. Aims: To determine how external factors including weather conditions affect seabird counts in a land-based seabird monitoring project (Red de observación de Aves y Mamíferos marinos, RAM project; Sea...

In the last few decades, there has been a remarkable development of niche models to help understand the ecological response of species to current rapid environmental changes. In the present study, we applied niche modelling to the predator community of the northern and northwestern shelf waters of the Iberian Peninsula to analyse the coexistence of...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...

The intensity of threats that marine habitats are suffering is increasing and they are mostly driven by anthropogenic pressures (e.g. overfishing or pollution). In addition, non-directly anthropogenic driven threats are also becoming serious threats due to global changes (e.g. extreme weather events or increasing of temperatures). In Europe, the EU...

Pelagic fishes and crustaceans represent a key component of the pelagic realm from an ecological point of view. This pelagic community plays a crucial role in ecosystem functioning due to its intermediate trophic position between plankton and marine top predators. In addition, inter-specific interactions might influence on the population dynamic of...

During the last decades, several fish stocks have been seriously reduced whilst others have shifted poleward following the displacement of their thermal habitat. Although top predators have been proved to dampen the fluctuations of their prey populations by foraging opportunistically, their life-history traits and their position at the top of the f...

Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community led open-source database of biodiversity time se...

In habitat modelling, environmental variables (e.g. depth, slope, sea surface temperature) are assumed to be good indicators of lower trophic levels distribution and thus good proxies of top predator’s distribution. However, as marine top predators are supposed to be mostly sensitive to prey abundance, the use of more proximal variables, such as pr...