Fig 1.
Area of the food web model (about 61,000 km2) applied to the Strait of Sicily.
Table 1.
List of the fleet segments considered by the combination of vessel size (i.e. length overall = LOA) and fishing gear.
Table 2.
Summary description of 72 biological functional groups.
Fig 2.
Comparison of variables and parameters for species with detailed stock assessments.
(A) Comparison of biomass and catches used in the Ecopath model (x-axis) and other sources of information (y-axis). Biomass (t km-2): gray = Ecopath vs stock assessment, white = Ecopath vs MEDITS corrected for catchability, orange = Ecopath vs acoustic-survey only for ENG (g) and SAR (h). Catches (t km-2 y-1): black = Ecopath vs stock assessment. (B) Comparison of annual mortality rates (y-1) used in the Ecopath model and stock assessments. Whiskers indicate MAX and MIN used in stock assessments for different age classes corresponding to Ecopath stanzas. Gray dot = Fishing mortality (F), white square = natural mortality (M) or sum of predation and other mortality (M2+M0), black dot = total mortality (P/B or Z). a = HAK2, b = HAK3, c = HAK4, d = MUL2, e = MUL3, f = PAG, g = ENG, h = SAR, i = ARF, l = PWL.
Fig 3.
Functional groups (nodes) by trophic levels (TL, y-axis) and by benthic (gray), demersal (yellow) and pelagic (cyan) domains (x-axis). White nodes represent fishing activities and the market (Mk). Links width are proportional to flow intensity, i.e., to annual food consumption rates for FG (>5^-6 t km−2 year−1), to catches for fleets and to landings for the market. Node radius is proportional to the square root of FG biomass, total catch of fleets and total landings for the market. Gray arrows indicate higher fluxes. Red arrows are loops (cannibalism).
Fig 4.
BPC by flux (consumption) of functional groups (FG) acting as consumers (left) and as sources (right) on the 2 other domains they do not belong to.
Pelagic (cyan), demersal (yellow), benthic (gray), lower trophic level groups are excluded.
Fig 5.
Direct effects of fishing on the 3 domains: Exploitation rate (E) by FGs (left) and cumulative exploitation rate (Cum E) by fleet (right).
FGs belonging to pelagic (cyan), demersal (yellow) and benthic (gray) domain. Details of fleets and FGs in Tables 1–2.
Fig 6.
Direct and indirect effects in the SoS food web.
Black arrows are positive effects, red arrows are negative effects. Arrow thickness is proportional to MTI (min = 0.03, max = 0.95). The 72 FGs are distinguished into main domain (benthic, demersal, pelagic) and by TL. Their overall cumulative effect in the web is proportional to the dimension of the circle.
Fig 7.
BPC explored by overall impact among 69 living functional groups.
FGs are displaced on radial axes representing the domain which they belong to: pelagic (P, cyan), demersal (D, yellow), benthic (B, gray). Arrow thickness is proportional to the overall impact they have on the remaining domains as well as the impact FGs received by the domains (size nodes) they do not belong to. Higher overall impact (black arrow) are from the most impacting FGs to side nodes and from side nodes to the most impacted FGs detailed in Table 2.
Fig 8.
Results of the MTI analysis for fleets of the SoS ecosystem model.
(A) overall impact across biological functional groups. (B) conflicts (negative values of MTI) and benefits (positive values of MTI) among fleet segments.
Fig 9.
BPC mediates mixed fisheries: Main fleet and biological overall impacts (direct and indirect) through the three domains.
Gray cloud = benthic domain, yellow cloud = demersal domain, blue cloud = pelagic domain. From left to right the fleets represent: bottom trawl, pair and mid-water trawl, purse seine and longline.