How to sustain healthy marine ecosystems and food webs

Could you provide a brief overview of your project – what are the main objectives and expected outcomes?

“Marine ecosystems provide us with a range of important resources and ecosystem services, such as fish for food, storage of carbon, production of oxygen and areas for recreation. The species that support these resources interact with each other in complex networks called food webs. But marine ecosystems and food webs are under many pressures including fishing, climate change and excess nutrients.”

 “My research focuses on understanding how these multiple pressures affect the complex interactions between species in the Baltic Sea and how we can manage these pressures to sustain healthy food webs. We can use this increased knowledge of species interactions and how they are affected by pressures to inform ecosystem-based management. Ecosystem-based management acknowledges the complexity of the system and employs measures to ensure that biodiversity is maintained, all resources are used sustainably, and ecosystem services are available to humans across society.”

“One of the central driving forces in the Baltic Sea food web is the humble herring. Herring are heavily fished commercially both as a food source for humans as well as for fish meal. They are also important prey for seals and in turn they prey on species lower in the food web. But are there enough herring for everyone? I use long term data sets, covering several decades back in time, and look at patterns and trends to see how the food web has evolved in response to environmental changes and human-induced pressures. In a recent study we looked at changes in the Bothnian Sea food web and environment over 42 years. We found that herring was increasingly affected by overfishing. Over time this has led to smaller herring  and less herring biomass. Environmental changes have also led to less available prey for herring, at the same time as seal numbers and natural predation has increased.”

How does your research relate to the One Health concept?

“The One Health concept encourages a holistic approach to the sustainable use of natural resources, and healthy food webs are vital to support functioning marine ecosystems and the sustainable use of marine resources. Herring are crucial for small-scale coastal fisheries and a key target species for industrial-scale pelagic offshore fisheries, which have more than doubled since the early 2000s. By examining the factors affecting food web dynamics we can propose management actions to ensure herring as a resource is used sustainably in a way that secures both sustainable future production of food and animal feed, and healthy food webs.” 

What do you consider the key challenges and opportunities in your research area concerning biodiversity and health?

“The current model of single-species management in the Bothnian Sea has not maintained the long-term resilience of the food web or ensured future food security. Single-species management only considers the growth of a single species population when setting fishing quotas. To ensure long-term sustainability there is a need to shift towards ecosystem-based management of resources.”

“However, to effectively implement ecosystem-based management we need to have a thorough understanding of how species interact with each other and how they are affected by a range of environmental and human-driven pressures. A key challenge is that there are still many gaps in our understanding of how the complex Baltic Sea ecosystem functions, which my research aims to address by improving our understanding of how Baltic Sea food webs are influenced by human and environmental pressures. This supports the development of sustainable management strategies which consider the whole ecosystem, in line with the One Health concept.”