A study conducted at the Department of Biology and CESAM – Centre for Environmental and Marine Studies of the University of Aveiro, as part of the PhD research carried out by Ana Sofia Tavares, analysed samples from stranded porpoises in Portugal collected between 2005 and 2013. The results, published in the journal Marine Pollution Bulletin, reveal concerning levels of persistent organic pollutants (POPs) in the species, with potential negative impacts on their health.
The porpoise population (Phocoena phocoena), a marine mammal inhabiting the Portuguese coast, is classified as “Critically Endangered” in the Red Book of Mammals of Mainland Portugal. As a top predator in the food chain, this species is particularly vulnerable to the bioaccumulation of highly toxic contaminants, which degrade slowly and remain in ecosystems for decades.
According to the study, POPs may interfere with the animals’ immune and reproductive systems, making them more susceptible to infections and diseases while reducing their reproductive capacity. The researchers also observed that adult males showed higher concentrations of these pollutants compared to adult females.
According to Ana Sofia Tavares, who is part of the research team together with Sílvia Monteiro, CESAM/DBIO researcher, and Catarina Eira, CESAM researcher and professor at the Department of Biology of the University of Aveiro, this difference may be explained by the transfer of these compounds from mothers to offspring during gestation and later through lactation.
This process is particularly concerning, as calves and younger animals receive high pollutant loads at a stage when their immune and metabolic systems are still underdeveloped, making them more vulnerable to the harmful effects of these substances.
The findings are especially relevant given the small size of the porpoise population along the Portuguese coast, which also faces other significant threats, such as accidental capture in fishing nets. The loss of genetic diversity detected in recent decades may further limit this population’s ability to respond to emerging threats, including pollution from emerging contaminants.
In this context, the researchers highlight the importance of continuous monitoring of persistent organic pollutant levels in order to assess their long-term impacts and support effective conservation strategies for this population.
Original news published in: UA Notícias, 13 May 2026.