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

2017 ◽  
Vol 372 (1717) ◽  
pp. 20160067 ◽  
Author(s):  
Thomas W. Cronin ◽  
Jeffry I. Fasick ◽  
Lorian E. Schweikert ◽  
Sönke Johnsen ◽  
Lorren J. Kezmoh ◽  
...  
Keyword(s):  
Light Attenuation ◽  
Early Summer ◽  
Visual Sensitivity ◽  
Calanus Finmarchicus ◽  
Cape Cod ◽  
Eubalaena Glacialis ◽  
Large Numbers ◽  
Right Whales ◽  
North Atlantic Right Whales ◽  
Dim Light

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 throughout their foraging range. Looking laterally, the whales might also be able to see copepod patches at short range near the surface. This article is part of the themed issue ‘Vision in dim light’.

Distribution, demography, and behavior of North Atlantic right whales (Eubalaena glacialis) in Cape Cod Bay, Massachusetts, 1998-2013

2018 ◽  
Vol 34 (4) ◽  
pp. 979-996 ◽  
Author(s):  
Charles A. Mayo ◽  
Laura Ganley ◽  
Christine A. Hudak ◽  
Solange Brault ◽  
Marilyn K. Marx ◽  
...  
Keyword(s):  
North Atlantic ◽  
Cape Cod ◽  
Eubalaena Glacialis ◽  
Cape Cod Bay ◽  
Right Whales ◽  
North Atlantic Right Whales ◽  
And Behavior

scholarly journals Anomalous 1992 spring and summer right whale (Eubalaena glacialis) distributions in the Gulf of Maine

2020 ◽  
pp. 209-223 ◽  
Author(s):  
Robert D. Kenney
Keyword(s):  
Gulf Of Maine ◽  
Late Summer ◽  
The Philippines ◽  
Early Summer ◽  
Calanus Finmarchicus ◽  
Small Scale ◽  
First Year ◽  
Eubalaena Glacialis ◽  
Right Whale ◽  
Right Whales

No right whales (Eubalaena glacialis) were sighted during aerial surveys in May-July 1992 in the Great South Channel region of thesouthwestern Gulf of Maine. This was the first year that spring surveys failed to detect right whales in this region. During the latespring/early summer season when right whales would normally be expected in the Great South Channel, a few were sighted in the centralGulf of Maine, none were found in their usual late summer/early autumn feeding areas near Nova Scotia and a few were seen inMassachusetts Bay. The absence of right whales in the Great South Channel in 1992 can be attributed to a shift in the regional zooplanktoncommunity. The usual spring zooplankton of the region is strongly dominated by the calanoid copepod Calanus finmarchicus, verticallyand horizontally aggregated into dense patches which are the preferred foraging areas of right whales. The 1992 zooplankton was dominatedby pteropods, distributed evenly throughout the water column. It is possible, although unlikely, that pteropods are unacceptable prey forright whales. A more likely explanation is that their local densities within small-scale patches were below the energetic threshold requiredfor successful right whale feeding. The shift in zooplankton dominance in 1992 is likely related to significantly reduced water temperaturesand a delay in the development of the usual hydrographic structure of the region. The 1992 temperature and hydrographic anomalies, inturn, can be attributed principally to an unusually large influx of colder and fresher Scotian Shelf Water, and may have been enhanced bywidespread cooling of the Northern Hemisphere caused by sulphuric acid haze in the atmosphere from the June 1991 eruption of Pinatubovolcano in the Philippines.

scholarly journals Summer and fall habitat of North Atlantic right whales (Eubalaena glacialis) inferred from satellite telemetry

2005 ◽  
Vol 62 (3) ◽  
pp. 527-543 ◽  
Author(s):  
Mark F Baumgartner ◽  
Bruce R Mate
Keyword(s):  
North Atlantic ◽  
Environmental Variables ◽  
Gulf Of Maine ◽  
High Surface ◽  
Chlorophyll Concentration ◽  
Calanus Finmarchicus ◽  
Eubalaena Glacialis ◽  
Bay Of Fundy ◽  
Right Whales ◽  
North Atlantic Right Whales

Satellite-monitored radio tags were attached to North Atlantic right whales (Eubalaena glacialis) in Grand Manan Basin of the lower Bay of Fundy during the summer and early fall seasons of 1989–1991 and 2000. Monte Carlo tests were used to examine the distribution of the tagged whales in space and time and with respect to a variety of environmental variables to characterize right whale habitat on their northern feeding grounds. These environmental variables included depth, depth gradient, climatological surface and bottom hydrographic properties, and remotely sensed surface temperature, chlorophyll concentration, and their respective horizontal gradients. Site fidelity in the Bay of Fundy was very low during 1989–1991 and high during 2000. When the tagged animals left the Bay, they did not frequently visit the deep basins of the Gulf of Maine and Scotian Shelf, where abundances of their primary copepod prey, Calanus finmarchicus, are thought to be high. Instead, right whales visited areas characterized by low bottom water temperatures, high surface salinity, and high surface stratification. No evidence was found that the tagged right whales associated with oceanic fronts or regions with high standing stocks of phytoplankton.

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