Humpback whale near a vessel. The escalation in global maritime traffic increases the risk of collisions and disturbances to marine wildlife. / Alan Bedding / Pixabay

The continuous growth of global maritime traffic poses a range of increasing threats to marine biodiversity, such as pollution, vessel collisions, and behavioral disturbances to species. In this context, a scientific team—led by the University of Algarve (Portugal) and involving the Doñana Biological Station of the Spanish National Research Council (CSIC) has revealed inadequate coverage of Marine Protected Areas and underscores the necessity of intensifying conservation measures.

The research, published in Biological Conservation, details the global analysis carried out, which identified regions where high biodiversity coexists with either intensive or sparse shipping activity.

Nearly 90% of all international trade goods are transported by sea. Beyond its economic importance, this activity is crucial for food security, energy distribution, and access to essential goods. "Nevertheless, its effects on marine biodiversity are extensive and severe, particularly on large animals such as cetaceans, seals, sea lions, turtles, and seabirds," the authors state in the article.

To better understand how and where these impacts occur, the team identified regions where high species richness coincides with high, low, or zero maritime traffic density. The first —which they termed Priority Mitigation Areas— are primarily concentrated in coastal zones, especially in the Central Pacific, the Southern Indian Ocean, and the South Atlantic. The second, identified as Priority Preservation Areas, are mainly located in the high latitudes of the Southern Hemisphere, where human presence is lower but high biodiversity exists. Meanwhile, areas with no maritime traffic are largely limited to polar regions and remote oceanic zones.

However, only a small fraction of these three identified regions possesses any type of protection. Overall, in zones with no maritime traffic, Marine Protected Areas cover barely 12%. Priority Preservation Areas (where biodiversity is high and traffic risk is low) are protected at 15%, while Priority Mitigation Areas (where maritime traffic and biodiversity coincide most intensely) reach 16%.

Regions featuring a total ban on extractive activities, such as fishing, are even scarcer. They cover 6.8% of zones without maritime traffic, 9.5% of Priority Preservation Areas, and 5.6% of Priority Mitigation Areas.

“These data clearly demonstrate significant gaps in marine biodiversity protection and underscore the necessity of strengthening conservation measures and the planning of maritime traffic on a global scale,” explains Marcello D’Amico, researcher at the EBD-CSIC.

Policies for better conservation

The study lays the groundwork for defining policies that address the ecological challenges of maritime transport and help achieve the 30x30 global biodiversity target, which aims to protect 30% of marine areas by 2030. "The identification of zones with sparse maritime activity and areas where biodiversity coincides with high traffic density provides an objective basis for guiding marine spatial planning and management decision-making," explains D'Amico.

The researchers advise officially designating areas with zero or sparse maritime traffic and high biodiversity, and prioritizing their integration into the network of Marine Protected Areas. For zones with intensive maritime activity, they propose specific strategies to mitigate impacts, such as reducing vessel speed (which can decrease underwater noise and collision risk) and optimizing shipping routes to circumvent the most sensitive areas.

This work falls within a broader research line at the EBD-CSIC that studies how infrastructure affects biodiversity. This experience has allowed the knowledge acquired about terrestrial impacts to be transferred to the marine realm, promoting the idea of considering maritime traffic as yet another form of infrastructure with significant environmental effects.

“We want to emphasize the value of this work as an example of how conceptual frameworks developed in terrestrial ecology can be successfully applied to the marine environment. This integration between disciplines allows us to more fully address the impacts of transport on biodiversity, regardless of the setting in which they occur. Furthermore, the study reinforces the importance of international collaboration and the use of open global data to advance toward a more coherent and sustainable management of the oceans,” concludes D’Amico.

The Centre of Marine Sciences of the Algarve, Nord University, the University of Évora, and the University of Lisbon also collaborated on this work.

Reference

Mestre, F., D'Amico, M., Bastazini, V.A.G., Assis, J., Jacinto D., Marçalo, A., Ascensão, F. Mapping global shipless areas and conflict zones between shipping and large marine vertebrates. Biological Conservation. DOI: 10.1016/j.biocon.2025.111431.

Comunicación

Estación Biológica de Doñana - CSIC

prensa [at] ebd.csic.es