The application of an age-structured model to the north Aegean anchovy fishery: An evaluation of different management measures

• Published in: Mathematical biosciences Vol. 237; no. 1-2; pp. 17 - 27
• Main Authors: Politikos, D.V., Tzanetis, D.E., Nikolopoulos, C.V., Maravelias, C.D.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.05.2012
• Subjects: Age Factors; Age structured model; Anchovy; Animals; Conservation of Natural Resources; Fisheries - methods; Fisheries management; Fishes - growth & development; Fishing strategy; Greece; McKendrick–Von Foerster equation; Models, Biological; Northern Aegean Sea; Numerical Analysis, Computer-Assisted; Population Dynamics; Greece; MED, Aegean Sea; Fishing strategy; Age structured model; McKendrick–Von Foerster equation; Northern Aegean Sea; Fisheries management; Anchovy
• ISSN: 0025-5564; 1879-3134
• DOI: 10.1016/j.mbs.2012.03.002

► The significance of the prespawning period on anchovy stock recovery is indicated. ► Additional management measures require a minimum of four years to benefit the stock. ► Anchovy population can be considered viable based on the persistence study. The objective of this paper is the integration of existing biological and fishery knowledge of anchovy into a unified modelling framework in order to advance our understanding of species’ population dynamics under different fishing strategies. The model simulates the anchovy biomass by combining an age-specific growth equation and a continuous age-structured population model based on the McKendrick–Von Foerster equation. Model predictions were compared to the biomass estimates and annual catches during the period 2003–2008. The present work provided direct evidence for the significance of the prespawning period as a critical life period for the management of anchovy stock in the Aegean Sea. It was found that the introduction of additional management measures could increase the profits in the long run for the fishery. However, for these to become apparent they will require a minimum of four years. Results also indicated that the reduction of fishing mortality directed at the spawning stock (recruitment overfishing) and the selective harvesting of younger individuals may be a plausible means of increasing stock’s total anchovy biomass. Finally, as a criterion of long-term population survival, we have considered the mathematical notation of persistence. The numerical criteria of persistence in the present model indicated that the anchovy population could be considered viable.