Threat assessements

Assessment of the impacts of transboundary and local pollution

Many of the project areas are located in the proximity to the potential pollution sources such as oil transfer terminals, ports or shipping routes. Intensive ship traffic endangers marine Natura 2000 sites both via discharge of ballast waters and with waste liquids from engine rooms. Most of discharged hazardous substances enter the food chain and can cause survival problems for marine organisms. Although this threat is well recognized, the actual impact on marine Natura 2000 sites is poorly known and quantified. Therefore a clear need to evaluate risk factor caused by pollution on the project areas has been realised.

The project aims to measure and assess the impacts of the hazardous substances to the project areas as well as to identify the sources of pollution, including transboundary and long-distance/diffuse pollution.

At the beginning of action methodological meeting has been organised to agree about substances to be analysed, schedule of the sampling actions as well as data handling procedures.

Sampling of molluscs and sediments is carried out in 6 Estonian project areas, 3 Latvian project areas and 2 Lithuanian project areas. The sampling in Estonia and Latvia is performed in frame of the benthic habitat inventory by scuba diving method, while in Lithuania a separate cruises are carried out and samples are obtained by dredge and grab sampler. Further the heavy metals are analysed in the sampled molluscs (Mytulis edulis sampled from hard bottoms and Macoma balthica sampled from sandy bottoms) and poliaromatic hydrocarbons as well as total oil are analysed in the sediment samples.

The obtained results will be used to assess pollution threats for each project area and to develop recommendations to be included in the management plans.

Assessment of dredging and dumping activities in project areas

Since active harbour construction and developing activities are carried out in the all three Baltic States, the impact from dredging and dumping activities is considered as one of the biggest potential threats to marine habitats in the coastal sea areas. The latest studies show that this impact might be much larger that it has been commonly estimated before, which calls for proper assessment procedure of these type of activities.

The aim of this action is to perform example assessment of the impact of dredging and dumping activities in project areas by using computer modelling.

Assessment will be performed in the coastal waters at the 6 Estonian, 10 Latvian and 3 Lithuanian sites. All the sites have previous history of either dredging or dumping activities and are located in close vicinity of natural values to be protected by Natura 2000 network. The project group has agreed that each national team will use their own approach to the assessment. The harmonisation and comparison of results will be carried out on the assessment product level.

Estonia has chosen a four step assessment procedure, first screening the ruling environmental conditions of the model sites, then characterising the documented dredging and construction activities and identified impacts, which is followed by establishment of functional relationships between environmental variables, biological communities and impact of construction and dumping activities, and finally creating a GIS model on impacts of construction and dumping.

As Latvia does not have data on habitats and biological communities in these areas, it will be doing modelling of sediment flow from dump sites and then using these models for indicating different zones with different probability of sediment spreading. The output of this modelling will be impact zones in GIS maps.

Similar approach will be used by Lithuanian team mostly focusing on modelling of sediment dispersal from the dredging and dumping sites under different environmental and climatic conditions. Sediment spread will be modelled by applying hydrodynamic model of the coastal zone. Further impacts will be evaluated using GIS techniques.

The main outcome of the activity will be the report combining and analysing the activities carried out in the three countries. This will include analyses of the different assessment techniques and development of recommendations for management plans.

By-catch assessment

Since most valuable waterbird wintering grounds often overlap with the areas of intensive fisheries, the birds by-catch in the fishermen nets is inevitable. According to the preliminary studies, up to 15% of wintering birds maybe killed such way in the fishermen nets. This is of course, is a great loss for waterbird populations, in certain cases also on the global scale (e.g. Eastern Baltic waters are one of the globally most significant wintering ground for the Stellers Ider).
However, detailed knowledge about the level of by-catch is not really known well. Therefore the project will address this issue by investigating the by-catch threat to waterbird population. Moreover, the project will also assess the by-catch level of marine mammals, such as Grey seal, as well as damage to the fishermen nets made by these animals. The damage of nets is a big issue having negative impact for fishermen activities and since those deaths of seals caused by by-catch should be dealt inline with how to minimise the damage for fishermen, the project will assess the level of damage of the fishermen nets as well.

Information on birds and marine mammals by-catch in fishing nets as well as on seal damage to fishing nets and fish catches will be collected from fishermen and by means of experimental fishing done by scientists. During the project, agreements will be made with selected fishermen who would be delivering caught birds and marine mammals to the project scientists. Alternatively the project experts carrying out the experimental fishing activities will also record the by-catch.

The collected data will be analysed to reveal the most dangerous fishing gear types and methods, the most vulnerable bird species and other aspects of bird and marine mammal by-catch. As a result of the assessment, the project will provide recommendations for the mitigation of fisheries impact on migrating and wintering waterbirds and marine mammals by regulatory measures and for the reduction of seal damage to fisheries.

Assessment of the impact of disturbances on waterbird and seals species of Community interest

This project activity will be as a desk study where screening of available information regarding different disturbance factors towards waterbirds and seals will be performed. The information will be compiled taking into account disturbance factors such as ship transport, recreational activities, windmill operation and construction, military activities. During the analysis of possible disturbance impacts, the information gathered during waterbird and seals inventory as well as existing and potential plans for economic activities will be integrated in order to estimate the real potential of the threats.

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