Scientists from around the world have gathered in Wellington this week to discuss new standards for understanding the world's ocean ecosystems that could lead to new approaches to managing fisheries and other marine exploitation. More than 50 scientists from the United States, Canada, Europe, Australia and New Zealand have been looking at a mathematical modelling system known as MICE (Models of Intermediate Complexity in Ecosystems), which helps to measure wider interactions in marine ecosystems, said Alistair Dunn, a fisheries scientist for the New Zealand government's National Institute of water and Atmospheric Research. While scientists already knew a lot about the behavior of separate components of ocean ecosystems, such as individual fish species, and how they responded to impacts like fishing, they still knew little about how the changes in one population or part of the ecosystem would impact the rest. "These mathematical models allow us to explore how different theories of change will impact the future, and will be used to develop management strategies that are robust to future uncertainty," Dunn said in an e-mail interview with Xinhua. "For example, if an exploited fish species is a prey of another exploited species, we can model this effect and see what happens when we include this interaction, and how our management of one species might affect the other one. Eventually we hope to determine how best to manage groups of fished species together, recognizing how they are linked," he said. "While this is a fairly simple example that has been well studied, it becomes more difficult when we expand the links that we consider -- for example, complex interacting food webs; changes in species distributions as a result of environmental variability; human influences such as pollution, erosion and sedimentation on our coastal marine systems; benthic impacts of fishing and ocean mining and climate change effects such as ocean acidification and warming." MICE models had real potential to provide scientific and objective advice to policy makers. They had already been used in some instances as decision-making tools by policy makers internationally, such as linking the effect of fishing prey species and their larger fish predators in the Baltic Sea as a way of better estimating sustainable fishing levels, he said. "Managing our marine systems requires us to trade-off some impact against use. We rely on our marine systems for a range of uses including food, employment, cultural identity and recreation. These tools allow use to consider these trade-offs to ensure we are making the best use of our resources while ensuring sustainability," said Dunn. Humans were an important part of the ecosystem and were always present in the models. "Models that ignore either the human impact on ecosystems or utilization of the ecosystem by people have limited utility. MICE models explicitly include human factors. MICE are used to provide advice to managers on the effects of different potential decisions, " said Dunn. "MICE allows us to address question such as: How will the system respond to change? How will our objectives be met under different scenarios? What factors have the most influence on outcomes?" Scientists were still learning how to best deploy the new methods and were still learning the consequences of the new approach, including how to best present complex scientific ideas and model results to managers and policy advisors. "The main challenge the workshop is addressing is how to develop and implement these new tools. The workshop brings some of the best and brightest minds in the world together, allowing us to learn from each other and make progress towards making these models the new standard."                                                                                                                                                             Xinhuanet