Periodic Reporting for period 1 - FEAST (Fine scalE forAging Strategies of grey seals in relation to their biotic and abiotic environmenT)
Período documentado: 2019-02-01 hasta 2021-01-31
Apex marine predators, such as pinnipeds, play a key role in top-down processes and are considered bio-indicators of the health of marine ecosystem. In addition, understanding the way marine predators sense and use their environment to find and maximize resource acquisition is crucial because it determines their survival and reproductive success. However, gathering concurrent information on the movements of marine predators, their prey and in situ environment at appropriate spatio-temporal scales is crucial but challenging. The limiting factors of existing methods include coarse time-space resolution, complicated logistics, invasive techniques and the lack of validations of inferences made on predator-prey interactions.
Via the very recent advent of the smallest yet developed acoustic logger, it was now for the first time possible to harness the immense potential in studying the foraging ecology of pinnipeds with high rate on-board logging of acceleration and acoustics. Accelerometers have proven to be efficient in detecting prey capture attempts in pinnipeds and penguins as well as quantifying the energetics expenses associated with diving and foraging activity. Further, the development of acoustic recording tags has allowed biologists to get on-animal perspective of their auditory scene and, in combination with movement sensors (i.e. accelerometer, magnetometer and GPS), to relate sounds to the activities of the tagged animal. For instance, breathing sounds have been used to estimate foraging costs while combined active and passive acoustics allow for estimation of prey size and prey field densities encountered by the animal. In addition, their use in studying the effects of habitat disturbances on marine mammals have significantly informed conservation efforts. Finally, echoes received from active acoustic would allow to acquire fine-scale information on the environment used by animals instead of using coarse satellite and/or database products, i.e. sea-ice, seafloor.
Via the very recent advent of the smallest yet developed acoustic logger, it was now for the first time possible to harness the immense potential in studying the foraging ecology of pinnipeds with high rate on-board logging of acceleration and acoustics. Accelerometers have proven to be efficient in detecting prey capture attempts in pinnipeds and penguins as well as quantifying the energetics expenses associated with diving and foraging activity. Further, the development of acoustic recording tags has allowed biologists to get on-animal perspective of their auditory scene and, in combination with movement sensors (i.e. accelerometer, magnetometer and GPS), to relate sounds to the activities of the tagged animal. For instance, breathing sounds have been used to estimate foraging costs while combined active and passive acoustics allow for estimation of prey size and prey field densities encountered by the animal. In addition, their use in studying the effects of habitat disturbances on marine mammals have significantly informed conservation efforts. Finally, echoes received from active acoustic would allow to acquire fine-scale information on the environment used by animals instead of using coarse satellite and/or database products, i.e. sea-ice, seafloor.
In FEAST, we combined in a novel manner, the use of acceleration and acoustic data (passive and active acoustic) to quantify the links between pinnipeds foraging decisions and energetics with 3-D prey distribution using two species of coastal seals : the harbour and Weddell seals as highly relevant model species. Firstly, harbour seals target small fish (of commercial interest) in the shallow, temperate waters of Denmark generating almost inevitable interactions with human activities. We can also access harbour seal both in the wild and in captivity allowing for critical validation of both ecological and methodological assumptions before applying them to wild conspecifics and other species. In contrast, Weddell seals target bigger prey in colder, deeper water in an extreme but pristine environment, Antarctica. This allows for a unique comparison of niche specific foraging strategies among pinnipeds in two contrasting environments.
The originality and innovative aspects of FEAST lied at the intersection of bioacoustics, cutting edge engineering tools, signal processing, ecology and physiology to determine foraging optimization in free-ranging wild animals and how it can, ultimately, impact their individual fitness. In accomplishing FEAST objectives, I provide unprecedented tools, datasets and results to further understand the ecology of pinnipeds to ultimately address data gaps in assessing the potential impact of human activities and environmental changes on coastal marine mammals. This will be directly relevant to several of the objectives aimed by the European Commission’s Marine Strategy Framework Directive.
These are the objectives we addressed in FEAST:
WP1b: Quantify harbour seals’ fine scale foraging activity and associated energetic budgets to investigate how they optimize resource acquisition.
WP2b: Estimate prey type and field densities using active acoustic and D-Tags to simultaneously record seals’ foraging behaviour as well as direct information on the quality of the prey patch encountered.
WP3b: Estimate the body condition of wild seals, which is an important determinant of ecological fitness, from aerial images acquired from unmanned vehicles.
Research methodology and approach: To address these WPs, FEAST required the concomitant acquisition of the horizontal (GPS track) and vertical movements (dive profiles and 3D acceleration) as well as passive and active acoustics of the seals. Passive acoustic allows to record sounds associated with the surroundings of the seals but also provides access to physiological inferences, such as breathing sounds. Active acoustic allows getting information on objects that are in front of the seals, such as the prey they target. To do so, I took advantage of the latest development of D-Tags and sonar tags – size reduction, extended battery life, combination of movement sensors (i.e. GPS, magnetometer and accelerometer) – that were deployed on harbour and Weddell seals. Finally, recent advances in unmanned aerial vehicle (UAV) technology, and its increased accessibility have made UAVs an attractive tool for wildlife research and monitoring. UAVs offer a safe and inexpensive tool to collect data from individuals (i.e. behaviour and morphometric)
The originality and innovative aspects of FEAST lied at the intersection of bioacoustics, cutting edge engineering tools, signal processing, ecology and physiology to determine foraging optimization in free-ranging wild animals and how it can, ultimately, impact their individual fitness. In accomplishing FEAST objectives, I provide unprecedented tools, datasets and results to further understand the ecology of pinnipeds to ultimately address data gaps in assessing the potential impact of human activities and environmental changes on coastal marine mammals. This will be directly relevant to several of the objectives aimed by the European Commission’s Marine Strategy Framework Directive.
These are the objectives we addressed in FEAST:
WP1b: Quantify harbour seals’ fine scale foraging activity and associated energetic budgets to investigate how they optimize resource acquisition.
WP2b: Estimate prey type and field densities using active acoustic and D-Tags to simultaneously record seals’ foraging behaviour as well as direct information on the quality of the prey patch encountered.
WP3b: Estimate the body condition of wild seals, which is an important determinant of ecological fitness, from aerial images acquired from unmanned vehicles.
Research methodology and approach: To address these WPs, FEAST required the concomitant acquisition of the horizontal (GPS track) and vertical movements (dive profiles and 3D acceleration) as well as passive and active acoustics of the seals. Passive acoustic allows to record sounds associated with the surroundings of the seals but also provides access to physiological inferences, such as breathing sounds. Active acoustic allows getting information on objects that are in front of the seals, such as the prey they target. To do so, I took advantage of the latest development of D-Tags and sonar tags – size reduction, extended battery life, combination of movement sensors (i.e. GPS, magnetometer and accelerometer) – that were deployed on harbour and Weddell seals. Finally, recent advances in unmanned aerial vehicle (UAV) technology, and its increased accessibility have made UAVs an attractive tool for wildlife research and monitoring. UAVs offer a safe and inexpensive tool to collect data from individuals (i.e. behaviour and morphometric)
Understanding the sensory and energetic avenues marine predators adopt to maximize resource acquisition in relation to their environment is fundamental to: 1. quantify how changes in prey distribution and availability, due to environmental changes and anthropogenic activities such as commercial fisheries, may affect population dynamics of the studied species; 2. inform on the ecosystem status in order to facilitate more effective conservation and management decisions (e.g. implementation of Marine Protected Areas, re-assessing marine resource intake numbers, marine spatial planning for infrastructure developments such as OREs).
Altogether, this project, its overall scope and the position it led to are opening new avenues for research collaborations with Aarhus university where research focuses on the impact of noise on marine mammals as well as broadening its scope in the context of ORE development which are both particularly important for the European Commission’s Marine Strategy Framework Directive, societal, economical and environmental issues.
This MSCA and the skills acquired as part of the training program implemented in the MSCA has allowed K. Heerah to secure a permanent position at France Energie Marines (FEM). FEM has hired K. Heerah for her long-time expertise on marine mammals and the bio-acoustic expertise she has acquired during her MSCA fellowship at Aarhus University. FEM is a research institute for the energetic transition where K. Heerah is coordinating and developing research projects to study marine mammals and seabirds in relation to Offshore Renewable Energies. K. Heerah will use the work and tools developed during the MSCA to feed new projects on the marine megafauna in the context of ORE developments.
Altogether, this project, its overall scope and the position it led to are opening new avenues for research collaborations with Aarhus university where research focuses on the impact of noise on marine mammals as well as broadening its scope in the context of ORE development which are both particularly important for the European Commission’s Marine Strategy Framework Directive, societal, economical and environmental issues.
This MSCA and the skills acquired as part of the training program implemented in the MSCA has allowed K. Heerah to secure a permanent position at France Energie Marines (FEM). FEM has hired K. Heerah for her long-time expertise on marine mammals and the bio-acoustic expertise she has acquired during her MSCA fellowship at Aarhus University. FEM is a research institute for the energetic transition where K. Heerah is coordinating and developing research projects to study marine mammals and seabirds in relation to Offshore Renewable Energies. K. Heerah will use the work and tools developed during the MSCA to feed new projects on the marine megafauna in the context of ORE developments.