Coping with copepods: do right whales (Eubalaena glacialis) forage visually in dark waters ... : Coping with copepods: do right whales (Eubalaena glacialis) forage visually in dark waters? ...

• Main Authors: Cronin, Thomas W., Fasick, Jeffry I., Schweikert, Lorian E., Johnsen, Sönke, Kezmoh, Lorren J., Baumgartner, Mark F.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: The Royal Society 2017
• Subjects: right whale; visual sensitivity; contrast vision; environmental radiometry; Calanus finmarchicus; Eubalaena glacialis; North Atlantic; Copepods
• Online Access: https://dx.doi.org/10.13016/m2xidc-iape; http://mdsoar.org/handle/11603/13300

North Atlantic right whales (Eubalaena glacialis) feed during the spring and early summer in marine waters off the northeast coast of North America. Their food primarily consists of planktonic copepods, Calanus finmarchicus, which they consume in large numbers by ram filter feeding. The coastal waters where these whales forage are turbid, but they successfully locate copepod swarms during the day at depths exceeding 100 m, where light is very dim and copepod patches may be difficult to see. Using models of E. glacialis visual sensitivity together with measurements of light in waters near Cape Cod where they feed and of light attenuation by living copepods in seawater, we evaluated the potential for visual foraging by these whales. Our results suggest that vision may be useful for finding copepod patches, particularly if E. glacialis searches overhead for silhouetted masses or layers of copepods. This should permit the whales to locate C. finmarchicus visually throughout most daylight hours at depths ...