Year-round movements of white-chinned petrels from Marion Island, south-western Indian Ocean

Abstract

White-chinned petrels Procellaria aequinoctialis L. are the most frequently recorded procellariiform species in the bycatch of Southern Hemisphere longline fisheries. Our study investigated the year-round movements of ten adult white-chinned petrels (seven breeders, three non-breeders/suspected pre-breeders) from Marion Island tracked with global location sensor (GLS) loggers for three years. Additionally, 20 global positioning system (GPS) tracks were obtained from breeding white-chinned petrels during incubation (n=9) and chick-rearing (n=11). All GLS-tagged birds remained, year-round, in the area between southern Africa and Antarctica, not making any major east/west movements. Three core areas (50% kernels) were utilized: around the Prince Edward Islands (PEI; incubation and early chick-rearing), c. 1000 km west of PEI (pre-breeding and early incubation) and around South Africa (non-breeding birds). The only area where 50% utilization kernels overlapped with intensive longline fishing effort was off the Agulhas Bank (non-breeding season). Our results confirm the lack of foraging overlap between the two subspecies; nominate birds (South Georgia/south-western Indian Ocean) utilize separate areas to P. a. steadi (New Zealand/sub-Antarctic islands), and thus should be treated as separate management units. Knowledge of the year-round movements of a vagile species, such as the white-chinned petrel, is important for its continued conservation.

Genomics detects population structure within and between ocean basins in a circumpolar seabird: The white‐chinned petrel

“…Introduced mammals can have substantial impacts Jouventin, Bried, & Micol, 2003), but mammal impacts can be challenging to tease apart from the effects of climate and fisheries bycatch (Barbraud et al, 2012). For example, white-chinned petrel recovery on Marion Island in the Prince Edward Islands is linked to removal of cats Felis catus (Dilley et al, 2017), and to the concurrent reduction of bycatch in longline fisheries (Rollinson et al, 2018).…”

“…The white‐chinned petrel ( Procellaria aequinoctialis Linnaeus) is an ideal model for exploring circumpolar relatedness and connectivity. They breed on subantarctic islands that ring Antarctica (Figure ), showing substantial natal and site fidelity like most seabirds (Burg & Croxall, ; Techow, Ryan, & O'Ryan, ), yet forage widely throughout temperate waters and the Southern Ocean (Table ; Catard, Weimerskirch, & Cherel, ; Perón, Delord, et al, ; Phillips, Silk, Croxall, & Afanasyev, ; Rollinson, Dilley, Davies, & Ryan, ; Spear, Ainley, & Webb, ). The white‐chinned petrel is the seabird species most frequently recorded as bycatch in Southern Hemisphere fisheries (Delord et al, ; Robertson et al, ; Rollinson et al, ), driving a need for defined conservation units with clear geographic boundaries.…”

“…Oceanographic zones are STZ subtropical zone; SAZ subantarctic zone; PFZ polar frontal zone; and AZ Antarctic Zone [Colour figure can be viewed at wileyonlinelibrary.com] and coastal shelf waters) compared with species that forage mostly inshore (Burg & Croxall, 2001;Clucas et al, 2018), and white-chinned petrels forage over very large distances in polar-temperate waters (e.g. Rollinson et al, 2018). The hypothesis of a multi-region structure, with stronger population-genetic (and potentially phylogeographic) differentiation, is based on evidence of morphometric and foraging-habitat differences in white-chinned petrels that do not align with a two-region structure (Barquete, 2012;Fraser, 2005).…”

Multidimensional stable isotope analysis illuminates resource partitioning in a sub‐Antarctic island bird community

“…Among the three small petrel species, female white-chinned and great-winged petrels both forage north of the Subtropical Front (the former slightly farther north as indicated by slightly higher δ 13 C memb ) during the pre-laying period, whereas blue petrels remain south of the Antarctic Polar Front. This conclusion is supported by shell oxygen data (see below) and by tracking data and atsea observations (Hockey et al 2005, Reisinger et al 2018, Rollinson et al 2018. Although diet studies suggest that great-winged petrels feed mostly on squids (Schramm 1986, Ridoux 1994, Cooper and Klages 2009, while white-chinned petrels prey more on fish (Ridoux 1994, Connan et al 2007), we found no difference in their δ 15 N values, likely reflecting high inter-individual variability combined with the effects of the Southern Ocean δ 15 N isoscapes (Jaeger et al 2010).…”

Foraging niche overlap during chick-rearing in the sexually dimorphic Westland petrel

“…However, the small maximum distance to the colony and home range area values recorded in the present study are in contrast with other Procellariiforms during breeding. For instance, the similar-sized congeneric white-chinned petrel Procellaria aequinoctialis displays much wider movements and exploits an area eight times bigger [ 46 , 85 , 86 ]. Even smaller Procellariidae and Hydrobatidae, species with lower flight capacity, display greater range and exploit a wider area [ 59 , 87 , 88 ] than the Westland petrel.…”