20 
Part B - Technical instructions 
Table 1.4: Beam trawl survey of epifauna. 
Baseline study 
Construction 
phase 
Operation phase 
Objectives 
Description of epifauna (macro 
benthos, demersal fish) in the 
project and reference areas. 
Medium and small scale survey 
of status quo, to be used as a 
basis for assessing possible im 
pacts of wind turbines. 
Medium and small scale survey of 
relevant operation phase impacts 
on species communities. 
Scope 
Once a year in autumn. In the first year of the baseline study, description of seasonal 
conditions in the project area and reference area requires investigations in spring and 
in autumn. 
The number of beam trawl per area (project/reference area) depends on the number of 
assessed infauna stations (see Table 1.3). Half of the infauna stations have to be sur 
veyed by means of beam trawls. In smaller areas (< 20 nmi 2 ), at least 10 beam trawl 
surveys should be conducted. 
Timing 
At least two consecutive and 
complete years prior to const 
ruction start. 
In the first, third and fifth year of 
the operation phase. 
Method 
Sampling strategy: 
• The sampling dates are to observe the same, limited time frame each year. The 
sampling interval in the project and reference area must not exceed 2 weeks. 
• The seasons are defined as follows: Spring: 01.03.-15.05./Autumn: 15.08.-15.11. 
• Equipment standard: 2 m beam trawl (mesh size 1 cm). Duration of ground-level 
trawling should be 5 min., trawling speed should be 1-3 kn. 
• Documentation of the sample processing method has to be provided 
(according to ISO/DIS 16665). The condition of the catching device must be 
documented. 
• Biomass shall be determined as wet weight per species 
(according to ISO/DIS 16665, Annex C). 
Moreover, the following information must be determined and documented: 
• Shooting and hauling positions, towing time, area covered. 
• Hydrographic (T, Sal, 0 2 ) and meteorological data. 
Presenta 
tion of 
results 
Documentation of condition and modification per project and reference area 
(described in separate chapters) by illustration of: 
• Total number of individuals per area/number of individuals per species and area 
(species table). 
• Total biomass per area/biomass per species and area. 
• Dominance structure (related to number of individuals and biomass). 
• Occurrence and distribution of Red List species. 
• Diversity/evenness for community analysis, cluster analysis or multi-dimensional 
scaling, univariate analyses, significance tests. 
• Evaluation according to BACI design with suitable statistical methods.