Ecosystem modelling of a deep-water system: evaluation of the effects of fisheries and management measures using Ecopath with Ecosim

• Main Author: Romagnoni, Giovanni
• Other Authors: Faculty of Science and Technology
• Format: Thesis
• Language: English
• Published: University of Plymouth 2010
• Subjects: Rockall Trough; Northeast Atlantic
• Online Access: http://hdl.handle.net/10026.2/1562

The effects of fisheries in a deep-water ecosystem are investigated through ecosystem modelling. An existent Ecopath with Ecosim (EwE) model from the Rockall trough (Northeast Atlantic Ocean) was modified to address questions on the future asset of the system. The aims of this study were a) to investigate the capability of the system to achieve a complete recover to the pre-fisheries level, and b) to observe the effects that fisheries and current management measures have on the system. The results showed that this system could attain a partial recover in case of a complete stop to fisheries within the next 30 years. The system could not, anyway, fully recover to the pre-fisheries level and several fish groups stabilized at a lower biomass level. These results suggests that the system could have been critically impacted by fisheries. The model also allowed to observe the effects of fisheries on target and non-target species and to critically evaluate the effectiveness of management measures. The results suggested that the effects of fisheries are felt throughout the system, also by non-target organisms. The current management system resulted to be effective, but not sufficient, to guarantee the recovery of fish stocks. Further protection is required, and future management measures should include ecosystem-level considerations. The importance of using the ecosystem-based approach to better understand and protect deep-water marine ecosystems is underlined by the results of this study Faculty of Science and Technology.