EU FP7 BENTHIS WP7 & EU-HELCOM BalticBOOST WP 3.2 Baltic Case - PowerPoint PPT Presentation

EU FP7 BENTHIS WP7 & EU-HELCOM BalticBOOST WP 3.2 Baltic Case Study: Femern Belt Fishing Impacts on Benthic Invertebrate Communities & Benthic Habitats J.R. Nielsen* ,1 , B.J.M. Vastenhoud* ,1 , Bossier, S.* ,1 , F. Møhlenberg* ,2 , F. Bastardie* ,1 , A. Christensen* ,1 , R. Diekman* ,3 , H. Gislason 1 , G. Dinesen 1 , O.E. Eigaard 1 , C. Pommer 1 , et al. Grant Agreement number: 312088 November 2016

Femern Belt Case Study: Example Invertebrate Sampling in Femern Belt Area: Femern Belt Project Figure 1. Grab and Frame sampling stations under the benthic invertebrate monitoring program and survey design (conducted by a consortium under Femern Belt A/S) repeatedly sampled in different seasons during 2009-2010. The stations are shown according to different types of benthic sediment types (physical habitats). Soft bottom is fine grained mud (sediment type 1), sand is sand (sediment type 2), and hard bottom is mixed sediments (sediment type 3) – EUNIS Level 3.

Sampling of Benthic Invertebrates Table 1. Overview of benthic sampling gears used, their sampling area, the area standardization and correction factor by gear, as well as the number of samples conducted with each gear and method. The upper table covers all benthic samples including the samples where the fishing pressure is 0 (1032 Samples), while the lover table only covers the samples where fishing pressure is above 0, (FP>0) (92 Samples). Sampling area (m 2 ) Sampling gear Area corrected Number of samples Van Veen Grab 0,0980 1,00 73 Van Veen Grab 0,1166 0,84 161 Dredge 0,1166 0,84 57 Dredge 0,1152 0,85 1 Kautsky frame 0,10 0,98 570 Rahmen (0.1 m 2 mit Netzbeutel) 0,10 0,98 186 Van Veen Grab 0,10 0,98 24 Van Veen grab 0,1152 0,85 2 Van Veen Greifer (0.1 m 2 ) 0,10 0,98 16 Sampling area (m 2 ) Sampling gear Area corrected Number of samples Van Veen Grab 0,0980 1,00 14 Van Veen Grab 0,1166 0,84 35 Dredge 0,1166 0,84 6 Kautsky frame 0,10 0,98 31 Rahmen (0.1 m 2 mit Netzbeutel) 0,10 0,98 9 Van Veen Grab 0,10 0,98 3 Van Veen Greifer (0.1 m 2 ) 0,10 0,98 2

Sampling of Benthic Invertebrates Table 2. Overview of the benthic invertebrate samples used in the present analyses including their spatio-temporal coverage. Furthermore, average fishing pressure by quarter by category is indicated as well as the minimum and maximum FP observed at stations in given category, i.e. the FP range included in the analyses. Number Total Total Total Average FP Minimum FP Maximum FP of Number Number of Biomass (Abrasion) (Abrasion) (Abrasion) samples of Species Individuals (B, g) (BD) (N) Samples with zeros All Samples 1032 363 21239021 8561,93 0,07 0 6,27 2009 544 336 12706816 4430,71 0,06 0 2,49 2010 488 292 8532205 4131,23 0,08 0 6,27 Season 1 519 326 8256748 4292,71 0,12 0 6,27 Season 2 429 323 12180556 4251,66 0,02 0 0,55 Season 3 84 66 801717 17,56 0,03 0 2,18 Habitat 1 80 194 1491435 2948,23 0,23 0 1,93 Habitat 2 172 174 1276999 257,62 0,03 0 0,89 Habitat 3 683 352 17678855 5316,94 0,08 0 6,27 Habitat 4 97 105 791732 39,14 0,01 0 0,34

Sampling of Benthic Invertebrates Number Total Total Total Average FP Minimum FP Maximum FP of Number Number of Biomass (Abrasion) (Abrasion) (Abrasion) samples of Species Individuals (B, g) per quarter per quarter (BD) (N) Samples with fishing pressure FP>0 All Samples 92 239 60068 2540,91 0,35 0,01 1,93 (6,27) 2009 50 215 29527 1090,93 0,27 0,01 1,56 2010 42 175 30541 1449,98 0,44 0,03 1,93 Season 1 63 218 35819 1765,63 0,46 0,01 1,93 Season 2 29 178 24249 775,28 0,10 0,04 0,55 Habitat 1 35 135 23663 1790,65 0,44 0,05 1,93 Habitat 2 3 55 977 21,36 0,39 0,03 0,87 Habitat 3 54 228 35428 728,90 0,29 0,01 1,78

Fishing Intensity and Fishing Pressure Indicator (Abrasion) Figure 2. Fishing intensity (FP) by Danish, German (and Swedish) vessels (>= 15 m length) fishing with towed gears (trawls, seiners, dredges) in the Femern Belt area in 2010. The Femern Belt invertebrate sampling stations are included in the map as well.

Fishing Intensity and Fishing Pressure Indidator • Fishing effort of hauled gears accumulated within 1000 m radius (alternatively 1500 m) around each of the benthic invertebrate sampling station during previous 3 months of sampling date (or during current sampling month); • The FP (fishing intensity) estimated as fraction of the area (ratio of surface) covered by fishery (accumulated fishing effort in the 1000 m radius during a 3 month period ) expressed as the total swept area ratio per quarter, i.e. the ratio between area swept and the total station area. • Accordingly, if FP=0.5 then only half of the 1000 m radius area is swept during the previous 3 month period which is the same as the full area is swept once after every second 3 month period. • The FP data resolution, processing and aggregation for estimating FP is following the EU-FP7-BENTHIS standards, and the EU FP7 BENTHIS WP2 software has been used for the process of estimating FP as described in Eigaard et al. (2016b) which is also based on previous work published in Bastardie et al. (2010) and Hintzen et al. (2012).

Fishing Impact BENTHIS Approach:

Factors analysed Dependent variables: • Bio-Diversity: benthic community species richness = No. species; • Density: Benthic community or species density = No. Individuals Biomass: Benthic community or species biomass= weight • Mean Size: Benthic community or species Biomass/Density Descriptive factors: Fishing pressure: Fishing intensity of hauled gears (OTB trawls, Seines, Dredges); sed_type: Benthic habitat type; EUNIS Level 3 Habitats; 1: Sublittoral Mud 2: Sublittoral Sand 3: Sublittoral Mixed Sediment (coarse sediment) t_min: Minimum bottom temperature (monthly minima at sampling position and time); s_min: Minimum bottom salinity (monthly minima at sampling position and time); o_min: Minimum oxygen concentration (monthly min. at sampling position and time); u_max: Maximum current speed (monthly maxima at sampling position and time);

Initial Correlation Analyses of Fishing Impact Benthic Community Density

Initial Correlation Analyses of Fishing Impact Benthic Community BioDiversity

Initial Correlation Analyses of Fishing Impact Mean Weight in Benthic Community: MW=Biomass/Density

Initial Correlation Analyses of Fishing Impact Correlation between BioDiversity and Density

Initial Correlation Analyses of Fishing Impact; FP>0. R Correlation Analyses using Lowess Smoother

Initial Correlation Analyses of Fishing Impact; FP >= 0. R Correlation Analyses using Lowess Smoother

Statistical modelling and multi-variate analysis of variance with a mixed GAM model: Models Tested Table 3. Overview of selected tested statistical models with different types of dependent and explanatory variables included, as well as model settings. The overall R-square of the model and the deviance (the proportion of the variability) in the data explained by the model are given as well. Model R 2 Model Mixed GAM Model analysed within the Deviance Number R statistical software Explained & AIC Excl. Incl. Excl. Incl. 0 FP 0 FP 0 FP 0 FP Model 2 Biodiv ~ log(N_ind) + FP_cum + t_min + s_min + o_min + 0,97 0,86 96,3% 85,5% (BioDiv, u_max + quarter + sed_type + (1|year) + s(lon,lat,k=75) Main (incl. quarter + all hydrographical factors, N log-transformed, Effects) smoother on spatial component with k=75) Model 4 Biodiv ~ N_ind + FP_cum + depth + sed_type+ (1|year) + 0.88 0,68 83,1% 70,8% te(lon,lat) (depth instead of hydrographical factors) Model 6 Biodiv ~ N_ind + t_min + s_min + o_min + u_max + quarter * 0,98 0,86 97,0% 85,7% (BioDiv sed_type * FP_cum + (1|year) + s(lon,lat,k=75) (Incl. 1 st order interactions between season, sed. type & FP, N; Interact. Effects) log-transformed, smother on spatial component with k=75) Model 7 N_ind ~ FP_cum + t_min + s_min + o_min + u_max + quarter 0,52 0,16 60,2% 30,1% (Density, + sed_type + (1|year) + te(lon,lat) Main Eff.) (No smoother on spatial component)