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ENVIROMENTAL RISK ASSESSMENT OF MARINE 5
INVASIVE SPECIES CARRIED BY BALAST WATER

for other ecosystems and countries for more accurate and specific risk assessment of invasive
species introduced to their national coasts. Prioritization of invaders, vessels and voyages by
this method provides better management of ballast water and better allocation of funds for
prevention of invasions.

2. Materials and Methods

2.1 Materials

Information and data of each individual invasive species were collected and integrated from a
wide variety of sources but the main resource was Ballast Water Management Status
Assessment Report for Turkey [15]. All 10 species presented in this study has been identified as
alien species in Turkish seas which are Black Sea, Mediterranean Sea, Marmara Sea and
Aegean Sea, according to the Ballast Water Management Status Assessment Report for Turkey.
The given information about invasive species were their scientific names, common names,
native ranges, non-native introductions and their ecological impacts on native ecosystems.

2.2 Environmental Risk Assessment

Environmental Risk Assessment (ERA) is a process that evaluates the likelihood or probability
that adverse effects may occur to environmental values, as a result of human activities. The
summary of steps in the ERA approach can be seen in figure 1.

Environmental risk assessment process starts with determining environmental pressure which
means an anthropogenic factor affecting some environmental values and processes. In our case
the environmental pressure was invasive species and their negative effects on native life in the
ecosystem.

Environmental value is a part of the environment which is significant to the ecosystem ecologically,
socially or economically. The term “value” does not refer solely its economic sense. When considering
marine invasive species, environmental values are;

 Native species
 Water quality
 Nutrient cycling
 Sedimentation process
 Community structure and food web
 Human health

For understanding the effects of the invasive species and actually to detect invasive species existence in
the environment some indicators are used. In ERA process, indicator means a parameter changing with
time and changes can be observed, measured and used for understanding what is happening in the
environment.

Many different kinds of indicators can be used including both living and nonliving assets giving
qualitative and quantitative information. Indicators used in this study are;

 Single species distribution change
 Population of native species
 Migration of native species
 Invasion rate of invaders

Sayı 5, 2016 GiDB|DERGi