Document ID: chunk:federal_register_of_legislation:F2022L00775:reg:18:p72
Version: federal_register_of_legislation:F2022L00775
Segment Type: reg
Provision Reference: reg 18 (pt 72/152)
Character Range: 239041–241988

At Staten Island, the numbers of Rockhopper Penguins decreased by 24 per cent between the censuses of 1998 and 2010 (Raya Rey et al. 2014). Between 1987/88 and 2012/13, numbers at Marion Island decreased by about 52 per cent, from 138,000 pairs to 65,000 pairs, equivalent to 72 per cent in three generations (Dyer and Crawford 2015). The long-term trends remain unknown for the Kerguelen and Crozet populations. Several other populations at the Auckland Islands and Antipodes Islands appear to have suffered severe declines of more than 40 per cent between the 1970s and the 1990s (Cooper 1992, Hiscock and Chilvers 2013).

Due to the difficulty in surveying this species (i.e. a high proportion of nests are cryptic in boulder fields and dense vegetation), population estimates, and trends are difficult to accurately obtain. In 1990, the population was estimated at 100,000–300,000 pairs on Macquarie Island and, in 1993, 166 pairs on Bishop and Clerk Islets (Brothers and Ledingham 2008). On Heard Island the estimate is 10,000 pairs and at least 10 pairs on McDonald Island (Woehler 1991, 1993; Ellis et al. 1998; Woehler 2006). Numbers on Macquarie Island were estimated at 32–43,000 pairs in 2006–2007 and work to develop and test survey methods to accurately estimate population trends on the island continues.

104 Wildlife Conservation Plan for Seabirds

Species profiles

No recent data from Bishop and Clerk Islets, Heard or McDonald Islands (Woehler 2006) but Heard Island population is believed to have decreased, based on disappearance of surface colonies between 1940s–1950 and early 2000s (E. Woehler pers. comm). Globally, this species has been classified as vulnerable under IUCN criteria owing to rapid population decreases, which, although they have been ongoing for perhaps a century, appear to have worsened in recent years.

Conservation Concerns and Actions
Climate change appears to be a factor driving population decreases. Survival of adult Rockhopper Penguins appears to be sensitive to sea surface temperatures, with highest survival probabilities under moderately-cold to long-term average temperature, and reduced survival probabilities under increasingly cold or warm ocean temperatures (Raya Rey et al. 2007, Dehnhard et al. 2013). Rockhopper Penguins at the Falkland Islands (Islas Malvinas) delayed breeding under warmer environmental conditions and laid lower mass eggs, with potential impacts on breeding success (Dehnhard et al. 2015a, b). Temperature extremes have caused collapse in accessible food resources in the past, and these are part of an ongoing trend in more frequent unusual oceanographic conditions recurring in the area (Dehnhard et al. 2013).
Penguins and their habitats may also be threatened by increased frequency of storm events at breeding sites (Wolfaardt et al. 2012). Severe mortality was recorded in moulting birds found unusually far from colonies in 2016, which appeared to