Marta Tobeña

Marta Tobeña
University of the Azores | UAc · Departamento de Oceanografía e Pescas

Msc

About

15
Publications
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Citations
Introduction
Marta Tobeña currently works at the Departamento de Oceanografía e Pescas, University of the Azores. Marta does research in Marine Biology.
Skills and Expertise

Publications

Publications (15)
Article
Full-text available
Efficient use of the energy budget is of fundamental importance for long-distance migrants, which must cope with seasonal energy demands and environmental conditions. Time-activity budgets can provide information on how animals balance energy use and acquisition over their annual cycle, and on the costs and benefits of different migratory strategie...
Article
Full-text available
Wide-ranging connectivity patterns of common bottlenose dolphins (Tursiops trunca-tus) are generally poorly known worldwide and more so within the oceanic archipelagos of Macaronesia in the North East (NE) Atlantic. This study aimed to identify long-range movements between the archipelagos of Macaronesia that lie between 500 and 1,500 km apart, and...
Article
Full-text available
Aim Understanding the environmental drivers of movement and habitat use of highly migratory marine species is crucial to implement appropriate management and conservation measures. However, this requires quantitative information on their spatial and temporal presence, which is limited in the high seas. Here, we aimed to gain insights of the essenti...
Article
The importance of seamounts as foraging hotspots for cetaceans depends on interactions between ocean flow and topographical features that concentrate prey. However, the oceanographic processes driving these aggregations are still unclear. Here, we analyzed two months of passive acoustic recordings from two remote seamounts in the Northeast Atlantic...
Article
Full-text available
Marine spatial planning and ecological research call for high-resolution species distribution data. However, those data are still not available for most marine large vertebrates. The dynamic nature of oceanographic processes and the wide-ranging behavior of many marine vertebrates create further difficulties, as distribution data must incorporate b...
Presentation
Full-text available
The Azores supported a sperm whaling industry for over one century and presently host a growing whale watching industry that mainly targets this species. Despite the lower productivity in relation to other coastal areas, the waters around the Azores are one important feeding ground for the species in the North Atlantic. Yet, very little is known ab...
Data
Marine spatial planning and ecological research call for high-resolution species distribution data. However, those data are still not available for most marine large vertebrates. The dynamic nature of oceanographic processes and the wide-ranging behavior of many marine vertebrates create further difficulties, as distribution data must incorporate b...
Article
Full-text available
A total of 313 individual common bottlenose dolphins Tursiops truncatus was photo-identified in four Special Areas of Conservation (SACs) in the western Canary Islands, Spain (El Hierro, La Palma, La Gomera and Tenerife), over a 10-year period (2001–2011). Of these, 36 individuals were resighted subsequently off two or more different islands, deter...
Article
Full-text available
An aggregation of live pyrosomes’s colonies (P. atlanticum) in the Canary Islands is registered for the first time. A total 337 of individuals were captured in a single set of midwater trawling, with average sizes of 179.29 mm (± 53.28 mm). Estimation of the carbon content of the colonies sampled was 2·10-4 g/m2 and 0’04 C g/m2. The importance of t...

Questions

Questions (2)
Question
These organisms were found in the whale's faeces, in Macaronesia region.
We though it can be a digestive system of an organism, but it's difficult to understand why it wasn't disgested. It can be a parasite?
Thanks for your help in advance
Question
I'm looking for records in Canary upwelling for a specific date. I do not know where to find this information.

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Projects

Projects (3)
Archived project
This project will support the Azorean Regional authorities in developing a strategy for its marine waters and enable the Region to comply with the requirements of the Marine Strategy Framework Directive. Specifically, this project aims to assist the Regional authorities in assessing the conservation status of cetaceans, by strengthening research in the areas of cetacean distribution, abundance and habitat requirements, population status and trophic interactions, and providing information on the potential impacts acting on cetaceans. Research objectives of this project are: 1) to improve our understanding of species distribution, abundance, and habitat use; 2) to improve our knowledge of specie’s diet composition and trophic relationships; 3) to build spatially referenced databases of socioeconomic activities that may impact cetacean populations; and 4) to provide advice on the location and design of future Marine Protected Areas. To achieve these objectives, the project will combine existing datasets available at IMAR-DOP/UAç with data collected using best available technologies and monitoring techniques of cetacean species. Our research team built a georeferenced database (with Geographic Information System) that contains 11 years (1999-2009) of cetacean sightings and search effort, collected during dedicated surveys or by the Azorean Fisheries Observation Program. These data will be used in association with remote-sensed environmental data (available at IMAR-DOP/UAç) to investigate spatial and temporal patterns of distribution/relative abundance of cetaceans, and to determine how these patterns are influenced by the biophysical characteristics and productivity of the ecosystem. Understanding this relationship will allow identification of preferred and suitable habitats for each species/group of species in the waters around the Azores. However, cetaceans are highly mobile and most species move freely beyond the areas normally surveyed by research vessels or crossed by fishing boats, making it impossible to understand how they use available habitats and aspects of their life cycles in these remote areas. Satellite telemetry is the only possible way to follow large-scale movements of cetaceans and to allow interpreting these in relation to oceanographic and physiographic data. Since 2008, our research team successfully tagged 16 baleen whales with satellite transmitters. In this project, we intend to continue this work and deploy another 15 satellite transmitters (already acquired with funding from other Agencies) on large whales to follow their large-scale movements and be able to determine their distribution and habitat requirements in remote waters of the Azores and beyond. Deployment will be performed following the same method used in the past: the tags will be remotely deployed with an airgun, and implanted into the blubber of the whales with surgical grade stainless steel darts. Information on the position of the instrumented whales will be relayed by the ARGOS satellite constellation and used to analyse the movements of the whales in relation to environmental variables, to identify foraging grounds, to determine how long the animals stay around the Azores and the importance of the area in their overall life cycle, and to examine stock structure and determine links with populations from other geographic areas. Passive acoustic techniques will also be used to monitor distribution, abundance and habitat use of cetaceans in selected areas. A network of moored hydrophones (already acquired by with funding from other Agencies) will be deployed to detect and locate cetacean vocalizations and echolocation sounds. Acoustic data are automatically recorded and stored on the hard disks of the hydrophones and then periodically downloaded to laptops. The spectrograms obtained will be analysed visually and with algorithms to identify the vocalizing species or groups of species, which will provide information on how each species uses the area throughout time. In addition, acoustic data may be used to estimate density and population sizes of some cetacean species, using distance-estimation methods similar to those applied to data from visual surveys. We will conduct boat-based surveys to collect skin and blubber tissue from live animals to conduct isotopic analyses (using nitrogen and carbon isotopes) to determine diet composition and trophic level of different species and to better understand food-web interactions between cetaceans and prey species. Samples will be obtained with biopsy darts that make use of a cylindrical punch attached to the end of a modified crossbow bolt. We will analyse the impact of specific human activities on cetacean populations and their ecosystem. Potential impacts can include physical disturbance from underwater noise (from coastal development, military operations and seismic surveys), ship collisions, bycatch in fishing gear, and disturbance from whale-watching boats. The analyses will encompass a description of the potential effects and an assessment of the perceivable or predictable threats posed by each activity. A georeferenced database will be created and used to determine degree of spatio-temporal overlap of cetaceans and human activities that may have adverse effects on species and their habitats. In the end, this information may be used to help designing future Marine Protected Areas in the Azores, based on the known movements and spatial requirements of cetacean species, while taking into account human use of the marine ecosystem.
Archived project
Though earlier telemetry studies by me [6] and other colleagues [7,17] provided critical insights into the movements of whales in relation to their physical environment, few attempts have been made to link movement patterns with intrinsic processes affecting their motivation to move. This project aims to elucidate the processes underlying movement decisions of whales, by assessing the influence of ecological, social and physiological factors on movement behavior at various spatio-temporal scales. My research addresses the following specific hypotheses: H1: Migrating whales forage at discrete stopovers instead of adjusting their movements to continuously track food resources; H2: Movements and behavior of whales at stopovers (Azores) are influenced by food availability, their nutritional condition (low fat stores/high nutritional stress) and energetic demands (pregnant/lactating females, juveniles); H3: Movements and behavior of sperm whales are influenced by characteristics of their social units (e.g. presence, number and size of calves; unit size and composition; matriarch size).
Project
Scientific research on wild cetaceans off La Gomera (Canary Islands, Spain) + public education + cooperation with the local whale watching operators to improve the conservation statues of the cetacean fauna in the Archipelago