<p>The present study aims to explore the dynamics of a fishery bio-economic system incorporating Berec’s encounter functional response to account for cooperative hunting among marine predators. The proposed model integrates market fish prices to vary with supply and demand, resulting in a system of four ordinary differential equations (ODEs) describing a couple of biological dynamics with variable market price and fishing effort. Moreover, to reflect realistic timescales, a slow–fast framework is considered, treating price dynamics as faster than biological processes and harvesting. A reduced (aggregated) three-dimensional model is then derived. The qualitative properties of the model, such as positivity and boundedness of solutions, are established. The aggregated system exhibits two possible outcomes: over-exploitation caused by excessive fishing (catastrophic equilibrium) and a sustainable state. A catch-control mechanism is introduced into the system and its feasible range is determined to prevent over-exploitation. To further investigate the system’s complex dynamics, local bifurcations are analyzed in detail. Employing Sotomayor’s theorem, a transcritical bifurcation is identified near the boundary equilibrium, while a Hopf bifurcation around the interior steady state confirms periodic behavior. Furthermore, a two-parameter bifurcation is also detected, including the generalized Hopf bifurcation. The study concludes with the formulation of an optimal harvesting policy that supports sustainable fishery management.</p>