I am currently working on density dependent effects in recovering North Sea fish stocks. Due to more strict fishing policies, some important fish stocks in the North Sea area are recovering. The increase in stock density can cause density dependent effects on processes such as growth, reproduction and fat accumulation. During my research I will focus on how to deal with these density dependent effects. More specifically, I will explore whether density dependence occurs and how yield can be optimized under these conditions. In addition, I will explore the suitability of stock assessment methods in populations with density dependence. During my project I will use Physiologically Structured Population Models (PSPM) with a foundation in Dynamic Energy Budget theory to explore how density dependence on different processes can emerge in a population.