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ai oi 9: Dive-depth and swim-speed of a juvenile and an adult free-ranging, Yangtze finless porpoises (Neophocaena phocaenoides) were observed using velocity-time-depth recorders in an oxbow of the Yangtze River. In total, 8222 individual dives were recorded over 59 hours. Two dive types, deep-dive...
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| Format: | Text |
| Language: | English |
| Published: |
2001
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.505.641 http://icesjms.oxfordjournals.org/content/59/2/438.full.pdf |
| Summary: | ai oi 9: Dive-depth and swim-speed of a juvenile and an adult free-ranging, Yangtze finless porpoises (Neophocaena phocaenoides) were observed using velocity-time-depth recorders in an oxbow of the Yangtze River. In total, 8222 individual dives were recorded over 59 hours. Two dive types, deep-dive (2.7 m) and shallow-dive, were recognized. Horizontal travel distances of two finless porpoises in a day were 94.4 km and 90.3 km, which were longer than those of oceanic relative species (harbor porpoises, Phocoena phocoena). Although the shallow water limited the maximum dive-depth, dive-duration, and bottom-time of finless porpoises were similar to the harbor porpoises. A sudden drop of swim-speed below 0.25 m s1 was frequently observed nearby the maximum dive-depth. This seemed to indicate ‘‘turning around’’ behaviour, possibly during prey pursuit. |
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