**4. Conclusion/discussion**

This demonstration has stressed the potential for applying a combined fine-scale Langrangian modelling design for improved prediction of the movements and intersections between an oil spill and seabirds. The oil spill risk modelling method provides a powerful tool for an initial screening of the potential impact on the various seabird species during a given period, even if the approach does not comply with a full risk assessment in line with the traditional MIRA class approach in Norwegian Waters [1]. Furthermore, combining the ABM model results of species movement directly with the result of oil particle movements provides consistent results independent of the grid mapping (i.e. results that are independent of the grid resolution). This makes results from different areas directly comparable.

More importantly, studies of the marine distribution of birds unambiguously point at the fine-scale distribution of most species of seabirds. Seabirds predominantly show an affinity to physical oceanographic properties such as fronts, upwellings and eddies, which enhance the probability of predators encountering prey [12–14]. In the Barents Sea this tendency is reflected in the ubiquitous concentrations of seabirds in the region of the Polar Front [15].

To accurately describe the overlap between the distribution of seabirds and oil slicks over time, one needs to be able to take account of the high degree of clustering and habitat association seen in seabirds. This solution can only be achieved with a Langrangian modelling approach like the one tested here. By using a standard Heuristic approach based on mean seasonal distrubutions of seabirds predicted impacts will unlikely resolve the true intersection in the distribution of the oil slick and the seabirds.

In other words, if high-resolution Langrangian models are not applied as part of the risk assessment of oil incidents mean values rather than in situ values for oil and seabirds predicted intersections will rarely match reality. As a result, risk assessments may lead to a type II error—a result estimating an impact in an area of low seabird density —or a type I error—a result erroneously pointing at a smaller or medium impact in an area where seabirds are highly concentrated. Thus, despite the large number of risk assessments of oil spills undertaken in the past accurate assessment of the impacts of oil slicks on seabirds remains a challenge.

*Combining Predicted Seabird Movements and Oil Drift Using Lagrangian Agent-Based Model… DOI: http://dx.doi.org/10.5772/intechopen.106956*

The combined fine-scale Langrangian modelling design seems to have a strong potential to pave the way for more realistic assessments of the concurrent distribution and movement of oil slicks and sensitive species of seabirds. Obviously, the calibration of the both the oil spill and seabird models requires that detailed empirical data are available regarding i) the oceanographic properties of the spill site, ii) the chemical composition of the oil and iii) the local density and distribution of the target species of seabird. Spatially refined assessments of the risk of seabird species sensitive to oil pollutions will enhance both the planning and environmental management of oil and gas exploration activities in the future.
