Gray whale densities during a seismic survey off Sakhalin Island, Russia
| Autor: | Valeriy Vladimirov, Laurie Ainsworth, Koen Bröker, Judy E. Muir, Roberto Racca, Glenn Gailey, Yury Bychkov, Sergei Starodymov |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
0106 biological sciences
Shore geography geography.geographical_feature_category Ecology biology Occupancy Whale 010604 marine biology & hydrobiology Seismic survey Botany Small population size 010603 evolutionary biology 01 natural sciences Predation Sound exposure Oceanography QL1-991 biology.animal QK1-989 Environmental science Whaling Zoology Nature and Landscape Conservation |
| Zdroj: | Endangered Species Research, Vol 29, Iss 3, Pp 211-227 (2016) |
| ISSN: | 1613-4796 1863-5407 |
| Popis: | Some whale populations that were severely reduced by commercial whaling have shown strong recovery since becoming protected, while others remain depleted and of high con- servation concern. Small populations are particularly susceptible to anthropogenic threats, in - cluding acoustic disturbance from industrial activities such as seismic surveys. Here, we investi- gated if sound exposure from a 16 d seismic survey displaced gray whales Eschrichtius robustus from their coastal feeding area off northeastern Sakhalin Island, Russia. We conducted multiple shore-based surveys per day, weather permitting, and created daily 1 km 2 density surfaces that provided snapshots of gray whale distribution throughout the seismic activity. A Bayesian spatio- temporal analysis was used to examine possible effects of characteristics of sound exposure from seismic airguns on gray whale occupancy and abundance. Models suggested highest occupancy in areas with moderate sound exposure. Slightly decreased densities were associated with sound exposure when the pattern for the previous 3 d was high sound on Day 2 and low sound on Days 1 and 3. Our findings should be interpreted with caution, given the low number of positive densities. This was due to success of the primary mitigation measure, which was to conduct the seismic survey as early in the feeding season as possible when few gray whales would be present. It is also possible that observed differences in occupancy and density reflect changes in prey availability rather than noise. Prey distribution and abundance data were unavailable for our study, and this important covariate could not be included in models. |
| Databáze: | OpenAIRE |
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