Long-term declines in common breeding seabirds in Japan

Abstract

SummaryGlobal seabird populations are in decline, with nearly half of all seabird species currently in an extinction crisis. Understanding long-term seabird population trends is an essential first step to inform conservation actions. In this study, we assembled historical breeding records of seabirds throughout the Japanese archipelago and quantified the long-term population trends of 10 major breeding seabird species using a hierarchical Bayesian state-space model. The model revealed that six species had increasing or no detectable trends (Short-tailed Albatross Phoebastria albatrus, Leach’s Storm Petrel Oceanodroma leucorhoa, Pelagic Cormorant Phalacrocorax pelagicus, Japanese Cormorant Phalacrocorax capillatus, Spectacled Guillemot Cepphus carbo, and Rhinoceros Auklet Cerorhinca monocerata). However, decreasing trends were found not only in nationally threatened species (Common Murre Uria aalge, and Tufted Puffin Fratercula cirrhata) but also common species that are often described as abundant (Black-tailed Gull Larus crassirostris and Slaty-backed Gull Larus schistisagus). These declining species have declined to 3–35% of baseline levels over the past 30 years. This study provides the first evidence of long-term declines in common and widespread seabirds in Japan.

Tufted Puffins exhibit low levels of genetic differentiation among breeding colonies in North America

“…They are currently listed as special concerns in California, as sensitive in Oregon, as endangered in Washington, and as imperiled in British Columbia (Hanson et al 2019). Additionally, this species has been in decline in Japan since the 1970s (Senzaki et al 2020). It has been suggested that population declines have occurred in response to rising ocean temperatures, which are thought to have shifted forage fish composition and distribution in the region (Jones et al 2019, Pearson et al 2023).…”