Ecological models are essential tools for studying complex marine food web structures, and for evaluating potential impacts of climatic changes and human activities in the past, present and future. The Nansen Legacy Research Focus 4 uses five different ecological models, in order to provide the most complete knowledge of the Barents Sea ecosystem. But how to compare and evaluate the outcome from these different models in a scientific and sound way?

This question was the motivation for two workshops with the objective to develop recommendations for best practice in evaluation of the performance of Barents Sea food-web simulation models used in the Nansen Legacy project.

The first workshop was held in Tromsø over two days in November 2018, and was attended by 13 participants from four institutions. Current practices in model evaluation for the five ecological models were reviewed, and workshop participants engaged in open discussions around specific topics related to model evaluation methods. Finally, an attempt was made to develop a first protocol for the standard reporting of model evaluation procedures.

The second workshop was held in Oslo on the 23-25th September 2019. The meeting was attended by 15 participants from five institutions. The objective of the workshop was to further develop the protocol for describing the evaluation of ecological models. The workshop started with a test of the evaluation protocol drafted during the first workshop in 2018. For this purpose, the evaluation protocol was applied to specific applications of six ecological models (Gomperz, Norwecom, Atlantis, NDND, EwE and NorCPM/ESM). In a second phase, workshop participants engaged into open discussions about the efficacy of the protocol, how well it could be understood, or how comprehensive it was. The workshop continued with group work, during which the different sections of the protocol were revised. These were reviewed and commented in plenary, revised again, and discuss in plenary again.

The result of these two workshops is a standard protocol for describing the evaluation of ecological models, which is abbreviated as the OPE protocol to reflect its structure: Overview, Patterns, Evaluation. The workshop results are being synthesized and are planned for submission to publication in the course of 2021.