Critically endangered western gray whales migrate to the eastern North Pacific

Western North Pacific gray whales (WGWs), once considered extinct, are critically endangered with unknown migratory routes and reproductive areas. We attached satellite-monitored tags to seven WGWs on their primary feeding ground off Sakhalin Island, Russia, three of which subsequently migrated to regions occupied by non-endangered eastern gray whales (EGWs). A female with the longest-lasting tag visited all three major EGW reproductive areas off Baja California, Mexico, before returning to Sakhalin Island the following spring. Her 22 511 km round-trip is the longest documented mammal migration and strongly suggests that some presumed WGWs are actually EGWs foraging in areas historically attributed to WGWs. The observed migration routes provide evidence of navigational skills across open water that break the near-shore north–south migratory paradigm of EGWs. Despite evidence of genetic differentiation, these tagging data indicate that the population identity of whales off Sakhalin Island needs further evaluation.

Download Full-text

Site-fidelity and spatial movements of western North Pacific gray whales on their summer range off Sakhalin, Russia

PLoS ONE ◽

10.1371/journal.pone.0236649 ◽

2020 ◽

Vol 15 (8) ◽

pp. e0236649 ◽

Cited By ~ 1

Author(s):

Koen C. A. Bröker ◽

Glenn Gailey ◽

Olga Yu. Tyurneva ◽

Yuri M. Yakovlev ◽

Olga Sychenko ◽

...

Keyword(s):

North Pacific ◽

Site Fidelity ◽

Western North Pacific ◽

Gray Whales ◽

Summer Range

Download Full-text

The Marine Boundary Layer Height over the Western North Pacific Based on GPS Radio Occultation, Island Soundings, and Numerical Models

Sensors ◽

10.3390/s19010155 ◽

2019 ◽

Vol 19 (1) ◽

pp. 155

Author(s):

Fang-Ching Chien ◽

Jing-Shan Hong ◽

Ying-Hwa Kuo

Keyword(s):

Boundary Layer ◽

North Pacific ◽

Western North Pacific ◽

Radio Occultation ◽

Marine Boundary Layer ◽

Numerical Models ◽

Layer Height ◽

Boundary Layer Height ◽

Atmospheric Instability ◽

Near Shore

This paper estimates marine boundary layer height (MBLH) over the western North Pacific (WNP) based on Global Positioning System Radio Occultation (GPS-RO) profiles from the Formosa Satellite Mission 3 (FORMOSAT-3)/Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites, island soundings, and numerical models. The seasonally-averaged MBLHs computed from nine years (2007–2015) of GPS-RO data are inter-compared with those obtained from sounding observations at 15 island stations and from the European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis (ERA-Interim) and National Centers for Environmental Prediction Global Forecast System (NCEP GFS) data over the WNP from 2012 to 2015. It is found that the MBLH using nine years of GPS-RO data is smoother and more consistent with that obtained from sounding observations than is the MBLH using four years of GPS-RO data in a previous study. In winter, higher MBLHs are found around the subtropical latitudes and over oceans east of Japan, which are approximately located within the paths of the North Equatorial Current and the Kuroshio Current. The MBLH is also significantly higher in winter than in summer over the WNP. The above MBLH pattern is generally similar to those obtained from the analysis data of the ERA-Interim and NCEP GFS, but the heights are about 200 m higher. The verification with soundings suggests that the ERA-Interim has a better MBLH estimation than the NCEP GFS. Thus, the MBLH distributions obtained from both the nine-year GPS-RO and the ERA-Interim data can represent well the climatological MBLH over the WNP, but the heights should be adjusted about 30 m lower for the former and ~200 m higher for the latter. A positive correlation between the MBLH and the instability of the lower atmosphere exists over large near-shore areas of the WNP, where cold air can move over warm oceans from the land in winter, resulting in an increase in lower-atmospheric instability and providing favorable conditions for convection to yield a higher MBLH. During summer, the lower-atmospheric instability becomes smaller and the MBLH is thus lower over near-shore oceans.

Download Full-text