Cetaceans play important roles in marine ecosystems and can be regarded as oceanic ecosystem engineers. By enhancing nutrient cycling and carbon storage and sequestration, cetaceans have the capacity to alter their environment. Whales release buoyant, nutrient-rich fecal plumes in surface waters that can stimulate phytoplankton growth, creating the essential foundation upon which marine life relies.

Conservation science can be said to have an additional requirement to ‘pure’ science – that is the need not only to do the best science possible and recognise its limitations – but the need to be able to influence decision makers and others of the need to take action to achieve the holy grail of good conservation status for populations and their environment. Almost inevitably, taking action will have socio-economic implications. The science itself is an essential, but not the only, factor that will be taken into account when politicians and managers make their decisions.

The principle that science provides the background for basic political decision making processes is tested today around the globe. While it is scientifically clear that climate change will reduce biodiversity worldwide, the installation of renewable energies is often rather seen as a foe than a friend to nature conservation. Conservation and climate protection are challenged by finding suitable solutions that quickly enable a basis for working together towards a common goal.

Although extinction due to climate change are still uncommon, they might surpass those caused by habitat loss or overexploitation over the next few decades. Among marine megafauna, mammals fulfil key ecological roles in the ocean, and the collapse of their populations may have irreversible consequences for ecosystem functioning. However, the biogeography, essential step for predicting effects of climate change on marine megafauna was not so far explored in the literature.

Sperm whales (Physeter macrocephalus) and long-finned pilot whales (Globicephala melas) are the most abundant species among the community of deep-diving cetaceans occurring off the west coast of Ireland, North-east Atlantic. To address a knowledge gap on these elusive species in an area subject to increasing levels of anthropogenic noise, fixed bottom-mounted autonomous acoustic recorders were deployed from 2014 to 2016 at thirteen locations.

Over the last two decades, the collection of hydrographic profiles from CTD attached to deep diving seals has been very successful in collecting data from the polar regions of the Ocean. A judicious choice of the species, sex and age of individuals makes it possible to obtain data in under-sampled regions such as areas of pack ice or continental shelves.

Marine species live in complex landscapes with scattered food and numerous disturbances that interrupt the animals’ normal foraging behaviour. Cetaceans are disturbed by noise from ships, seismic surveys, offshore construction work, etc., but the extent to which this influences the individuals’ energy balance depends on the time it takes till they can commence feeding after being disturbed. Animals that are able to move to alternative foraging grounds, or to return to the area they were scared away from, are thus less severely affected.