How bright is your beak? South Atlantic and southern Indian Ocean Sooty Albatrosses differ in genetics, morphology and ecological preferences

An incubating Sooty Albatross on Gough Island in the South Atlantic Ocean with a bright yellow sulcus, photograph by Michelle Risi

Dilini Abeyrama (University of Lethbridge, Canada) and colleagues have published in the journal Conservation Genetics on differences in two populations of the Endangered Sooty Albatross, suggesting that separate conservation management plans for the two populations be implemented to prevent the loss of evolutionarily significant units.

A brooding Sooty Albatross on Marion Island, southern Indian Ocean with a pale yellow sulcus, photograph by Michelle Risi

The paper’s abstract follows:

“The southern oceans are home to a large variety of organisms, including many endemic species. High levels of endemism are due in part to non-physical barriers limiting gene flow in marine species. The sooty albatross Phoebetria fusca is an endangered seabird breeding on seven island groups in Atlantic and Indian Oceans. We sequenced the mitochondrial control region (55 birds) and genotyped 10 microsatellite markers (88 birds) to examine the population genetics of sooty albatrosses from Tristan da Cunha and Gough Island (Atlantic Ocean), and Marion Island, Île de la Possession (Crozet) and Amsterdam Island (Indian Ocean), which together support > 99% of the global population. We also analysed the bill sulcus colouration and quantified stable isotope composition of body feathers of breeding adults from Gough and Marion Islands. Both genetic markers identified two clusters separating sooty albatrosses breeding in the Atlantic and Indian Ocean basins. Standardized colour analysis also separated populations in the two ocean basins and revealed the sulcus of sooty albatrosses on Gough Island is significantly more yellow than individuals on Marion Island. Stable isotope analysis of body feathers showed significantly higher δ¹³C values from Marion sooty albatrosses compared to Gough conspecifics, indicating different moulting areas. Sooty albatrosses breeding on islands in the two ocean basins differ from each other in their genetics, morphology and ecological preferences. Accordingly, it is recommended that separate conservation management plans be implemented for sooty albatrosses breeding in each ocean basin to prevent the loss of evolutionarily significant units.”

Reference:

Abeyrama, D.K., Risi, M.M., Connan, M., Ryan, P.G., Jones, C.W., Glass, T., Osborne, A.M., Steinfurth, A., Schofield, A., Pistorius, P., Keys, D. & Cherel, Y. & Burg, T.M. 2025.  Cryptic variation in the sooty albatross Phoebetria fusca: genetic and morphological differences between Atlantic and Indian Ocean birds.  Conservation Genetics 26. 117-128.

John Cooper, Emeritus Information Officer, Agreement on the Conservation of Albatrosses and Petrels, 05 March 2025