Interest in the economic potential of the oceans is increasing. In Norwegian waters, marine activities present many potential stressors to seabirds and migratory birds when crossing the ocean.
In the next decades, it is expected that there will be additional developments in activities making use of the marine and maritime sectors, under the name “blue growth”. However, growth in the blue economy could increase the cumulative stressors on marine habitats, impairing environmental conditions through loss of ecosystem functions, habitat, and biodiversity. The development of the offshore wind industry plays a key role in reducing greenhouse gas emissions, and Norway is amongst the European countries that has the best wind resources. As a result, wind power is one of the energy sources that has experienced the most rapid growth. However, there are many other industries being developed at sea which can put further pressure on the marine environment. MARCIS has set out to identify and map relevant novel marine stressors, including their expected development in Norway in the coming years, as well as their potential impacts on seabirds and migratory birds. The identified novel stressors can be categorized into three main groups: (1) energy production, (2) food production and farming and (3) other activities such as seabed mining, tourism, outdoor activities, and marine military training grounds.
Left: Cultivation trials with sugar kelp that Sintef Ocean carried out in offshore conditions on the coast of Nordmøre (Photo: SINTEF Ocean). Right: Schematic drawing of a Macroalgal Cultivation Rig. (Modified from Bak et al 2018)
There is a high degree of variability in the maturity level of the different novel stressors and, as such, the assessment of the potential impacts on seabirds and migratory birds has been either based on existing scientific publications or extrapolated from other types of stressors. The mechanism by which seabirds and migratory birds can be impacted by novel stressors may vary between stressors. The main effects can be generally categorized into lethal effects and sub-lethal effects. Lethal effects are those that result in direct mortality such as from collision, entanglement, by-catch, and pollution, whereas sub-lethal effects can be broadly categorized into those resulting from displacement from an activity or area, or attraction to it. Birds may be displaced because they are avoiding a structure creating a barrier for their movement, or because an area they usually depend upon is modified or destroyed. Displacement results in increased energy expenditure or reduced energy intake, which, in turn, can lead to decreased fitness and increased mortality. In other cases, however, birds may be attracted to certain marine activities. For example, some activities may provide roosting structures or result in an increased food availability. These effects may result in energetic benefits due to increased food intake and shorter flying distances, but they may also increase the risk of exposure to lethal effects.
To make best use of these findings in the MARCIS project, available maps of expected developments of novel stressors on the Norwegian continental shelf could be a useful addition to the MARCIS app. To be able to include novel stressors in the MARCIS app, it is thus important to continuously evaluate the need for updating map layers to keep up with these potential upcoming activities, and to consider including activities such as blue biotechnology, hydrogen production, and marine landfills of mine tailings, which are currently limited to fjords. Results from this part of the MARCIS project may help in the understanding of which pressures seabirds and migratory birds might face in the future, and which stressors may have to be included in future cumulative impact assessments.
Summary of the most relevant potential lethal and sub-lethal effects of novel stressors.