Introduction

Background

In complex oil spill response operations, focusing tactics and strategies is essential in order to optimise mitigation and reduce impacts on seabirds and other vulnerable biological resources. Along the more than 100 000 km of Norwegian shoreline, distribution of different species varies significantly over the year, and the coastal environment varies diversely in terms of water depth, extent of intertidal areas, and degree of wave exposure. In order to address these challenges, a set of priorities and strategies have been developed towards presence of ecological groups of seabirds and shorebirds, linked to the barrier philosophy of Norwegian oil spill response.

The priorities depend on a combination of temporal seabird and coastal seal habitat use and oil spill drift patterns linked to the oceanographic and seascape characteristics and needs to be linked to spill response tactics considering operational factors including water depth, wave exposure and access to the shoreline.

This approach allows for a systematic decision support, to be applied under the spill response planning as well as operations identifying which response units and tactics to be deployed where, depending on time of the year, presence of species and operational conditions of the coastal environment.

The barrier philosophy

On the Norwegian Continental Shelf (NCS), the Clean Seas Association for Operating Companies (NOFO) has developed an oil spill response structure where tactics and strategies from offshore to onshore spill operations are described for five distinct barriers (Figure 1).

• Barrier 1 – Offshore, near the source of the oil spill
• Barrier 2 – Offshore, along the oil drift trajectory
• Barrier 3 – Coastal areas
• Barrier 4 – Nearshore, oil in the tidal zone
• Barrier 5 – Stranded oil

While these barriers are based on the logic and logistics of oil spill response operations, they also have a geographic dimension, that may be linked to the presence and vulnerability of Valued Ecosystem Components (VECs) like seabirds and coastal seals.

Priority values and vulnerabilities

According to the Norwegian Environment Agency (NEA), the highest priority for protection in the case of oil pollution is for naturally occurring, non-compensable biological resources of high value and vulnerability. Priorities are given by applying the MOB model, using a scale from 1 to 3 on Value (Local to National/International) and Vulnerability (Low to High).

From application of this model, seabirds and coastal seals are the VECs that may achieve the highest score, thus the focus of the PriStrat project.

Data and information sources

Sources of information and data for this project include:

• SEAPOP
• NINA input to the NEA “Priority map” project
• Akvaplan-niva input to the NEA “Priority map” project
• Akvaplan-niva photographic material
• Akvaplan-niva Environmental Zoning System
• Vulnerability designations applied in environmental risk assessments
• Discussions with NINA and IMR

Approach

Recognizing the need for prioritisation of spill response resources in the case of a significant oil spill, our approach was for ecological groups of seabirds and species of coastal seal to identify periods of the year with heightened sensitivity accompanied by changes in distribution patterns.

From this, we identified what the focus of response should be in order to minimize the impact on each group and species. This information was linked to the individual barriers in oil spill response, and we further described what tactics and strategies could be applied to achieve the optimal response.

Other measures that could reduce the impact from an oil spill would be to apply hazing techniques to scare seabirds and seals away from an oil spill, lure or entice them away from the spill, and cleaning of oiled wildlife.