Distribution and abundance of western gray whales off northeastern Sakhalin Island, Russia, 2001’003
Open Access
- 17 August 2007
- journal article
- research article
- Published by Springer Science and Business Media LLC in Environmental Monitoring and Assessment
- Vol. 134 (1-3), 107-136
- https://doi.org/10.1007/s10661-007-9811-2
Abstract
In 2001’003, >60,000 km of aerial surveys and 7,700 km of vessel surveys were conducted during June to November when critically endangered Korean–Okhotsk or western gray whales (Eschrichtius robustus) were present off the northeast coast of Sakhalin Island, Russia. Results of surveys in all years indicated gray whales occurred in predominantly two areas, (1) adjacent to Piltun Bay, and (2) offshore from Chayvo Bay, hereafter referred to as the Piltun and offshore feeding areas. In the Piltun feeding area, the majority of whales were observed in waters shallower than 20 m and were distributed from several hundred meters to ∼ 5 km from the shoreline. In the offshore feeding area during all years, the distribution of gray whales extended from southwest to northeast in waters 30’5 m in depth. During all years, the distribution and abundance of whales changed in both the Piltun and offshore feeding areas, and both north–south and inshore–offshore movements were documented within and between feeding seasons. The discovery of a significant number of whales feeding in the offshore area each year was a substantial finding of this study and raises questions regarding western gray whale abundance and population levels, feeding behavior and ecology, and individual site-fidelity. Fluctuations in the number of whales observed within the Piltun and offshore feeding areas and few sightings outside of these two areas indicate that gray whales move between the Piltun and offshore feeding areas during their summer–fall feeding season. Seasonal shifts in the distribution and abundance of gray whales between and within both the Piltun and offshore feeding areas are thought, in part, to be a response to seasonal changes in the distribution and abundance of prey. However, the mechanism driving the movements of whales along the northeast coast of Sakhalin Island is likely very complex and influenced by a multitude of factors.Keywords
This publication has 22 references indexed in Scilit:
- Distribution and abundance of western gray whales during a seismic survey near Sakhalin Island, RussiaEnvironmental Monitoring and Assessment, 2007
- Feeding of western gray whales during a seismic survey near Sakhalin Island, RussiaEnvironmental Monitoring and Assessment, 2007
- A western gray whale mitigation and monitoring program for a 3-D seismic survey, Sakhalin Island, RussiaEnvironmental Monitoring and Assessment, 2007
- Seasonal distribution of minke whales Balaenoptera acutorostrata in relation to physiography and prey off the Isle of Mull, ScotlandMarine Ecology Progress Series, 2004
- Foraging patterns of gray whales in central Clayoquot Sound, British Columbia, CanadaMarine Ecology Progress Series, 2001
- GRAY WHALES (ESCHRICHTIUS ROBUSTUS) OFF SAKHALIN ISLAND, RUSSIA: SEASONAL AND ANNUAL PATTERNS OF OCCURRENCE1Marine Mammal Science, 1999
- Group size and seasonal pattern of occurrence of humpback dolphins Sousa chinensis in Algoa Bay, South AfricaSouth African Journal of Marine Science, 1999
- GRAY WHALE (ESCHRICHTIUS ROBUSTUS) HABITAT UTILIZATION AND PREY SPECIES OFF VANCOUVER ISLAND, B. C.Marine Mammal Science, 1998
- Habitat Use by Bottlenose Dolphins: Seasonal Distribution and Stratified Movement Patterns in the Moray Firth, ScotlandJournal of Applied Ecology, 1997
- Role of marine mammals in aquatic ecosystemsMarine Ecology Progress Series, 1997