Configuraciones básicas 49

Biodiversity, abundances and reproduction potentials of many species are under pressure from a range of human impacts, particularly fisheries. Fisheries impact target species, other (bycatch) species and habitats (seafloor integrity) as well as inter-specific competitive and predator-prey relationships between species. There is little discussion that the North Sea biodiversity is well under that of a 'pristine' state. How this impacts ecosystem functioning, e.g. at the level of sus- tainability of exploitation, is less clear.

The EU specifies many different GES indicators (EU, 2010) for GES 1 and GES 4. For the Dutch situation, the indicators of GES 4 are set equal to that of GES 1. As the indicators for GES 1 and GES 4 are equal for the Dutch situation, these two descriptors are difficult to separate and taken together here. The GES descriptors are (EU, 2008):

1. Biological diversity is maintained. The quality and occurrence of habitats and the distribution and abundance of species are in line with prevailing physio- graphic, geographic and climatic conditions.

4. All elements of the marine food webs, to the extent that they are known, oc- cur at normal abundance and diversity and levels capable of ensuring the long-term abundance of the species and the retention of their full reproduc- tive capacity.

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The Dutch indicators (based on an earlier version of DGSW, 2011) used for this study are:

- Trend in population size and distribution of representatives of long-lived/vul- nerable species of the benthic community, vulnerable bird species, and all regular occurring marine mammals (OSPAR EcoQOos);

- Size diversity index within the endangered and declining commercial and non-commercial fish species and vulnerable bird species;

- Distribution and pattern of habitats within the North Sea region (at EUNIS level 3).

Step 1: Gap analysis GES 1 and 4

As the target related to these indicators is not set yet, it is equally unclear how far we are currently removed from the targets of MSFD GES 1 and 4.

Nevertheless, as a wide range of fisheries-related measures is in place or under consideration, under the EU Common Fisheries Policy (CFP). Measures are directed at preserving the fisheries, the fish and other biota and certain hab- itat features such as Seafloor integrity (GES 6). The Commissioner of this study has stated that CFP is currently sufficient to bridge any gaps towards the tar- gets of GES 1 and 4 and that additional measures under the MSFD are not needed (see Textbox 3.1).

Step 2: Pressures

Most human use of the seas affect biodiversity and ecosystem functioning to some extent. Relative impacts of the multiple-use of the seas are difficult to pin- point, as these are rarely precisely measured and might interact with each oth- er. Broadly speaking, extinctions might be seen as the ultimate state of species loss and reduced ecosystem functioning. Impacts leading to extinctions were ranked by Brander (2010):

- Exploitation 55%

- Habitat loss 37%

- Invasive species 2%

- Climate change/pollution/disease 6%

In the North Sea, fisheries cause most abundance and species loss, as well as habitat loss or habitat degradation (e.g. Lindeboom 2005). As fisheries are being dealt with under the CFP rather than under the MSFD, there is little scope for further treatment in this study.

35 Step 3: Additional measures

Of the measures on the shortlist, two measures can have a direct effect on GES 1 and GES 4.

Measure 51: Hard substrate items in bottom protection zones

According to the workshop participants, 'Silent construction methods' is not an additional measure. The Netherlands included this measure in the porpoise pro- tection plan. This plan is carried out under N2000 and ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas). It is important to note that the porpoise protection plan is not area-specific, but generic to the whole NCP.

Step 4 and step 5: Description and quantification of the effect of the measures Application of this measure with the aim to introduce an artificial reef, resulting in locally higher biodiversity could be an option. The substrate type and the ex- act location determine the effect on biodiversity. The effect of introducing hard substrate for maintaining soil disturbance as an enforcement measures is ques- tionable. For example, introducing a ring around the Klaverbank requires a lot of rocks. The effect is that it is more difficult to fish. It is not desirable to have any stones in any habitat type, because the integrity of a specific habitat type is lost. The effect of the measure 'Hard substrate items in bottom protection zones' on GES 1 and GES 4 as enforcement measure is small, and in no relation to a measure as territorial protection.

The measure 'hard substrate items in bottom protection zones' can be made more specific by focusing on active recovering of shellfish banks (mussels oys- ters, spisula) The question is whether a measure as Marine Protected Areas will have the intended effect, in other words whether the natural dynamics of the system to return the animal shrill banks can be recovered in time. The answer to this question in unknown.

Uncertainty/certainty analysis

Should the CFP fall short in resolving all biodiversity and food web issues in the North Sea, additional measures, either under the CFP or under the MSFD might be considered. Before such additional measures can be considered, first a full gap analysis of all CFP is required. This falls outside the scope of the present study.

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Step 6: Costs per measure See Section 3.6.

Extra measures with an effect on GES 1 and |GES 4

A few new potentially attractive measures were put forward by the experts. These measures are not analysed in this study, but might be interesting enough to consider in next phases in the MSFD implementation process.

- Territorial protection as complement the birds and habitat directives. The determination of the size of this measure is a difficult choice.

- Protection of wrecks as point location for biodiversity (kind of artificial reefs) - Species protection measures (plans)

3.2 GES descriptor 2: 'Non-indigenous species introduced by human