Seminars

November 6 2009

3:30 LSB 2320

Brian Kot
Department of Ecology and Evolutionary Biology, UCLA

Rorqual Whale (Balaenopteridae) Lunge-Feeding Strategies, Behaviors and Mechanisms

Summary

Rorqual whales (Balaenopteridae) are the largest animals on earth yet their feeding systems are poorly understood due to the difficulties of locating and studying feeding whales at sea. Most rorquals feed by lunging into schools of fishes or krill with their mouth open. They engulf a large volume of water and prey then channel it into their expandable ventral pouch. Musculature and elastic material properties of the pouch then force water back out the mouth through a set of baleen plates which retain prey. Most previous work on rorqual feeding involved anatomical studies of dead whales or telemetric studies of living whales which were not observed feeding. Therefore, functional aspects of the feeding process remain highly speculative. My research involves capturing and comparatively analyzing film of rorquals while they are visibly feeding at the sea surface. During the summers of 2004-2007 I used inflatable boats, helicopters and aerial video systems to observe and record digital video footage of surface-feeding blue whales (Balaenoptera musculus), finback whales (B. physalus) and minke whales (B. acutorostrata) in the Gulf of St. Lawrence, Canada. From this video I identified different lunge-feeding modes and their frequency of use by each species and individual. I then tested them for correlations with different behavioral and environmental variables. Using videogrammetric techniques I then measured 15 different aspects of prey capture locomotion. Results from 1300 hours at sea and 3500+ lunge-feeding events from 39 blue whales, 10 finback whales and 62 minke whales showed that rorquals capture prey using six different lunge-feeding modes that are more dependent upon temporal aspects of their feeding behavior than spatial aspects of their feeding environment. Each mode shows different characteristics of feeding locomotion, including velocity, acceleration and lunging trajectory, that are statistically significant (P

 

 

 

 

 

 



 

 

 

 

 

 

 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



 



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