Baseline study of the distribution of marine debris on soft-bottom habitats associated with trawling grounds in the northern Mediterranean
Pilar Sánchez, Mercedes Masó, Raquel Sáez, Silvia de Juan, Alba Muntadas
and Montserrat Demestre
Baseline study of the distribution of marine debris on soft-bottom
habitats associated with trawling grounds in the northern Mediterranean
Sci. Mar. 77(2) : 247-255 - DOI: 10.3989/scimar03702.10A
SUMMARY: The present study aims to analyse the local and regional
variability in the density and typology of marine debris on fishing
grounds on the northern Mediterranean continental shelf, and to test
relationships between marine litter and trawl fishing activity.
Moreover, the colonization of plastics was examined in order to study
the importance of plastics as a source of impact on marine communities
and their further environmental implications. This study surveyed 11
sites, associated with trawling grounds and subjected to different
levels of fishing intensity, located in four areas of the Mediterranean:
one in Italy, the Central Tyrrhenian coast, one in Greece, the eastern
Ionian coast, and two in Spain, the Murcian and Catalan coasts. Samples
were collected during an oceanographic cruise undertaken from the 21 May
to the 24 June 2009. Results showed geographical variation in the
density of marine debris which ranged from 0 to 405 pieces per hectare
in the surveyed areas, plastics being the dominant components.
Variability within sites was higher than between areas, indicating
small-scale patchiness in the distribution of the debris over the
seafloor. Though the study areas were within trawling grounds, the
density of debris was not significantly correlated with fishing effort.
More than 30% of plastics were between 10 and 20 cm width/length, and
more than 40% of the plastics were colonized by a biofilm of
microorganisms, suggesting indirect effects on benthic communities.
Keywords: marine debris, seabed plastic accumulation, colonized benthic
plastics, northern Mediterranean Sea.