Doctoral dissertation assesses monitoring, assessment, and management of the spread of alien species associated with maritime traffic

Alien species arriving with ships can belong to almost any group of organisms. Okko Outinen’s dissertation assesses the temporal and regional coverage of all biological monitoring programs in Finnish marine management from the perspective of alien species. The dissertation also evaluates the impact of newly arrived species on native communities and examines how effectively ships can treat their ballast water to prevent the spread of new species during ballast water discharge.

The dissertation was conducted within the University of Helsinki’s doctoral program in interdisciplinary environmental sciences. It concerns on several fields of science and policy, from nature conservation to marine status assessments and global maritime legislation.

The dissertation is based on four scientific articles. These publications have developed monitoring methods for ports and marinas to improve the detection of new species and assessed the status of Finnish marine areas regarding alien species according to the criteria required by the European Union’s Marine Strategy Framework Directive. In addition, a new method for measuring biodiversity has been developed, which is suitable for all biological communities.

Preventing alien species is difficult

Preventing the spread of alien species has proven challenging despite the international convention on the control and management of ships’ ballast water and sediments.

“Samples taken from over 200 ships showed that only about half of the ships managed to treat their ballast water so that the treated water did not contain too many living organisms compared to the limits set by the ballast water convention,” says Okko Outinen.

The results of the dissertation can be applied to the development of biological monitoring in Finnish marine management and the assessment of the diversity of marine communities. Additionally, the results may indirectly help in developing new, more effective regulations to prevent the spread of organisms via biofouling of ships. There is currently no internationally binding legislation for ships’ biofouling management.

Doctoral defense and dissertation

Time: Friday 26 September 2025 at 12:00
Place: Porthania, PIII, Yliopistonkatu 3, Helsinki
Live stream
Language: English.
Dissertation: Monitoring, assessment, and management of the spread of aquatic non-indigenous species associated with maritime traffic: Interdisciplinary implications on a multilateral issue