We need to talk about the role of zooplankton in marine food webs.

Zooplankton are the key intermediary between primary production and the fish community and a cornerstone of marine food webs, but they are often poorly represented in models that tend to focus on fish, charismatic top predators, or ocean biogeochemistry. In this study, we use an intermediate complexity end-to-end food web model of the North Sea with explicit two-way coupling of zooplankton to phytoplankton and higher trophic levels to ask whether this matters. We vary the metabolic rate of omnivorous zooplankton (OZ) as a proxy for uncertainties in our understanding and modeling of zooplankton form and function, and moving beyond previous studies we look at the impacts on the food web in concert with climate warming and fishing.

Emerging issues in fisheries science by fisheries scientists.

The current epoch in fisheries science has been driven by continual advances in laboratory techniques and  increasingly sophisticated approaches to analysing datasets. We now have the scientific knowledge and tools to proactively identify obstacles to the sustainable management of marine resources. However, in addition to technological advances, there are predicted global environmental changes, each with inherent implications for fisheries.

LeMaRns: A Length-based Multi-species analysis by numerical simulation in R.

Fish stocks interact through predation and competition for resources, yet stocks are typically managed independently on a stock-by-stock basis. The need to take account of multi-species interactions is widely acknowledged. However, examples of the application of multi-species models to support management decisions are limited as they are often seen as too complex and lacking transparency.

What is multispecies MSY? A worked example from the North Sea.

The concept of an optimum yield at intermediate levels of fishing (the so called maximum sustainable yield or MSY) has been with us since the 1930s and is now enshrined in legislation as a key objective of fisheries management. The concept seems intuitively reasonable and is readily applicable to a single stock treated in isolation and assuming a constant environment. However, translating this concept into a mixed and multispecies fishery, where there are complex trade-offs between fleets and stocks and in general no simple optimum solution, has been problematic.

Evaluation and management implications of uncertainty in a multispecies size-structured model of population and community responses to fishing.

Implementation of an ecosystem approach to fisheries requires advice on trade-offs among fished species and between fisheries yields and biodiversity or food web properties. However, the lack of explicit representation, analysis and consideration of uncertainty in most multispecies models has limited their application in analyses that could support management advice.We assessed the consequences of parameter uncertainty by developing 78 125 multispecies size-structured fish community models, with all combinations of parameters drawn from ranges that spanned parameter values estimated from data and literature.