Duration: 6 months (M19 – M24)
Responsible: Dr. Stylianos Somarakis
Involved: Gkanasos, Triantafyllou, Somarakis, Tsiaras

Summary

WP3 (Hypothesis & scenario testing) is a model implementation package. Once developed and tested the end-to-end model will be used in a series of scenario simulations with the aim to identify climatic and human-related drivers of population variability and sardine/anchovy shifts. The effects of climate change, e.g., temperature rise; fresh water inputs (e.g. Black Sea water, rivers), eutrophication, as well as fisheries exploitation patterns will be evaluated. Alternative management options for the pelagic fisheries in the Aegean Sea will be tested (e.g. closed seasons, closed areas and different TAC levels -Total Allowable Catches) for the sustainable exploitation of the resources.

Objectives

The objective of WP3 is to assess the effect of changes in specific climatic drivers and of other anthropogenic pressures on the pelagic ecosystem and small pelagic fish populations through a series of simulations of the model developed in WP2. Small pelagic fish populations are closely linked to both environmental conditions (abundance of phyto/zooplankton, temperature, ocean circulation) and fisheries exploitation. The variability of primary production in the Aegean Sea is driven primarily by lateral (rivers, Black Sea water) nutrient inputs and the entrainment of deep water nutrients through vertical mixing. The impact of future climate changes (e.g. temperature rise, decrease in river output) on the productivity and, subsequently, on small pelagic fishes will be investigated by simulating scenarios adopting future climate conditions (e.g. IPCC-A1B). Alternative exploitation and management options for the pelagic fisheries in Greece will be simulated in order to evaluate the predicted effect on populations of fish and zooplankton

Description of work

Task 3.1 Climatic scenarios (Month 19-24)

1. Scenarios of changing ocean conditions. The end-to-end model will be used to perform scenario simulation, adopting present and future climate conditions (IPCC-A1B scenario) for the 1980-2000 and 2080-2100 periods. The climatic atmospheric forcing is provided from SINTEX-G (INGV-SXG, Gualdi et al., 2007), fully coupled global atmosphere-ocean general circulation model simulation produced in the EU project ENSEMBLES. The results will be analyzed in order to identify changes in anchovy and sardine populations and their habitats.
2. Scenarios of changing river nutrient inputs. The model will perform three scenario simulations, adopting different river nutrient inputs based on three socio-economic scenarios (Business as usual, Policy target, Deep Blue, Ludwig et al., 2010) for the 2030 period. These scenarios were adopted from the Mediterranean SESAME project. The impact of changing river nutrient inputs on the productivity of the Aegean Sea and small pelagic fish populations will be investigated.
3. Scenarios of changing Black Sea water/nutrient inputs. The outputs of the model will be evaluated after adopting different levels of water discharge, outflowing dissolved inorganic nutrients and organic matter from the Black Sea. Of particular interest will be the effects on the advection patterns of eggs and larvae, since the Black Sea water discharge is a significant determinant of the Aegean Sea circulation regime.

Task 3.2 Fisheries management scenarios (Month 21-24)

The model will be used to test:

• the effects of different options for temporal and spatial closures (closed periods, closed areas) as well as fishing fleet regulations on the population distribution, size structure, fecundity and transport patterns of early stages.
• the effect of implementing total allowable catches (TACs), an option that is currently being discussed in Scientific Committees for small pelagic resources in the Mediterranean will be evaluated

Deliverables

D3.1 Manuscript on definition and description of simulation scenarios (Month 21)

D3.2 Manuscript on results of different oceanographic & fishing management scenarios (Month 24)