Table 1.
Model input parameters of the Black Sea balanced model for 1995.
Fig 1.
Black Sea environmental and LTL biological outputs used as inputs and drivers in the HTL model.
(A) Depth (m); (B) Bottom oxygen (averaged over 1995–2021); (C) Temperature averaged over 50m (averaged over 1995–2021); (D) Salinity averaged over 50m (averaged over 1995–2021); (E) Small phytoplankton integrated over 50m (averaged over 1995–2021); (F) Large phytoplankton integrated over 50m (averaged over 1995–2021); (G) Small zooplankton integrated over 50m (averaged over 1995–2021); (H) Large zooplankton integrated over 50m (averaged over 1995–2021); (I) Primary production integrated over 50m.
Fig 2.
Energy flow and biomass diagram of the Black Sea ecosystem (1995).
Functional groups (grey) and fleets (red) are represented by nodes. The relative sizes of the nodes for functional groups are proportional to their biomasses in the ecosystem, whereas the relative sizes of the nodes for fishing fleets are proportional to their catch volumes (fishing fleets: Beach-Seiner, Trawler, Dredge, Gillnet and Trammel net, Longline, Traps and pods, Purse Seine, Midwater Trawl). The functional groups are ordered by their trophic levels (y-axis) and their preferred domain (bottom x-axis Pelagic vs Demersal vs Benthic). Predator–prey relationships are expressed with a gradient yellow (predator) to blue (prey) line. The graph was created by the authors using MATLAB vR2014b.
Table 2.
Summary statistics for the Black Sea and Mediterranean Sea.
Fig 3.
Mixed trophic impact relationships between functional groups and fisheries.
Positive values (from white to blue) indicate positive impacts, and negative values (from white to red) indicate negative impacts. “Green check mark” symbol indicates MTI value greater than 0.2, “yellow exclamation mark” symbol indicates MTI value between 0.2 and -0.2, “red cross mark” symbol indicates MTI value smaller than -0.2.
Fig 4.
Relative total impact (εi) versus keystoneness (KSi).
The size of the circles is proportional to the species/group biomass.
Fig 5.
Modelled biomass predictions of the best-fitted model.
Predictions (lines) versus observed (points) estimated by statistical stock assessments for the 1995–2021 period.
Table 3.
Comparison across selected stepwise fitting interactions.
Fig 6.
Biomass spatial distributions of the stock-assessed species.
Data are presented as t*km-2 averaged over all modelled years 1995–2021.
Fig 7.
Qualitative spatial validation of stocked assessed species.
Habitat capacity computed by Ecospace model (left panels) versus AquaMaps suitability maps (right panels).