Hopp til hovedteksten
Ecosystem illustration
Print friendly version

Atlantis

Atlantis (Fulton et al. 2007) is a so-called end-to-end model, which means that it includes more or less everything, from physics to fisheries. It has been tested and run actively in several places around the world, (nine model domains around Australia, and at the east and west coast of U.S.) and is at the moment being initialized areas around Hawaii, in the North Sea and, by IMR, in the Barents and Nordic Seas.

This is the first time it will be coupled with ice, and have the large seasonal variations in light as there are in the northern part of the model domain.

The model domain (fig. 1) is made of arbitrary polygons, which are defined based on information about the hydrography, depth and biology. There are 59 polygons, which covers an area of about 4x106 km2. In depth, the model has seven depth layers (0-50 m, 50-150 m, 150-250 m, 250-375 m, 375-500 m, 500-1000 m and 1000-1250). In areas where there are greater depths than 1250 m, the bottom layer can be stretched down to the bottom.

Figure 1Klikk for stort bilde

Figure 1

At the moment, the model includes 51 species and functional groups (fig. 2).  All species cannot be included; some have been gathered in functional groups. The gathering has been performed with the aim that the species included in a group should eat similar prey, have similar longevities and be in the same size class. It is not a good idea to group together prey and predators, or species that live for 2 years with one that lives for 40 years.

Figure 2Klikk for stort bilde

Figure 2

In addition to the biology, Atlantis also includes fisheries. This means that we will include time-series of catches and by-catches of the species/groups included in the model, in addition to number of vessels, type of gear and when they are at sea.

Atlantis gives great opportunities to run “what-if” scenarios. It can be used to look at the impact of climate, fisheries and pollution on the ecosystem as a whole. In the Barents and Nordic Seas this means that it for instance can be used to look at the vulnerabilities of the “ice-loving” species, like polar bears and seals, in connection to decreasing ice-cover and increasing temperatures. With respect to fisheries, it can give more information about the effect of changing gear, or reducing/increasing the number of vessels in certain areas.

Citations:

Fulton EA, Smith ADM and Smith DC. 2007. Alternative Management Strategies for Southeast Australian Commonwealth Fisheries: Stage 2: Quantitative Management Strategy Evaluation. Australian Fisheries Management Authority Report. 

Models

Models are by definition simplified representations of nature. Still they can give us valuable information about the physical, biological and population dynamic processes in the ocean. And in combination models can help us to gain insight and quantify the dynamics of the complex ecosystems.

Contact

Cecilie Hansen
984 31 016