Valerio Bartolino

Abstract Quantifying the impact of lower trophic level species abundance on higher trophic level predators (and vice versa) is critical for understanding marine ecosystem dynamics and for implementing ecosystem-based management. Trophic ecosystem models generally predict a tight coupling between prey and fish predators, such that higher abundance of lower trophic species results in abundance of higher trophic level predators.

1. INTRODUCTION 1 2. MATERIALS AND METHODS 3 2.1. Assessment data 3 2.2. Equilibrium age structure at FMSY and F0 3 2.3. ABI calculation 4 2.4. Correlation analysis and visualisation 6 2.5. Simulation testing 6 2.6. Receiver operating characteristics and evaluation of skill 7 3. RESULTS 7 3.1. Age structure relative to FMSY 8 3.2. Age structure relative to F0 10 3.3. Correlations 10 3.4. Simulations and ROCs 11 4. DISCUSSION 12 5.