Incidence of entanglements with marine debris by northern gannets (Morus bassanus) in the non-breeding grounds.
The quantification of entanglements of megafauna with plastic debris at sea is difficult to assess for several reasons, such as detection and reporting biases. We used standardized vessel based counts to describe and quantify the occurrence of marine debris entanglements in northern gannets Morus bassanus at five of its main wintering areas. We observed 34 entangled birds in total, representing 0.93% of all gannets counted (n=3672 individuals). The incidence of entanglements largely varied geographically, being exceptionally high off Mauritania (20.2% of the birds in late spring). Most birds affected were immature (1.88% compared to 0.06% in adults), which in turn represented 52.4% of all the birds. Entanglements in the lower bill mandible were the most frequent, mainly with red-colored plastic objects. Further research is urgently needed to evaluate the impact of entanglements at the population level and its occurrence in other marine species, and to seek potential solutions.
SEO/BirdLife, Delegación de Canarias, C/Libertad 22 (Pueblo Sabanda), 38296 La Laguna, Tenerife, Spain. Electronic address: benerguez@gmail.com.
Beneharo
B
Rodríguez
SEO/BirdLife, Delegació de Catalunya, C/Murcia 2-8, Local 13, 08026 Barcelona, Spain.
Juan
J
Bécares
Department of Evolutionary Ecology, Estación Biológica de Doñana (CSIC), Avda. Américo Vespucio s/n, 41092 Seville, Spain.
Airam
A
Rodríguez
SEO/BirdLife, Delegació de Catalunya, C/Murcia 2-8, Local 13, 08026 Barcelona, Spain.
José Manuel
JM
Arcos
D000818:Animals; D001717:Birds; D004784:Environmental Monitoring; D005398:Fisheries / Q000295:instrumentation*; D008435:Mauritania; D010969:Plastics; D014866:Waste Products / Q000032:analysis* / Q000706:statistics & numerical data
D010969:Plastics; D014866:Waste Products
Entanglements; Fishing; Mauritania; Non-breeding; Plastic debris; Seabirds