The high speed movements are similar to those of "Stripe" (PTT #840) emphasizing 50 - 100 

 fathom depths. Overall only 8% of PTT #843's dives were in less than 50 fathoms; 68% 

 were in 50 - 100 fathoms; and 24% were in the 100 - 500 fathom category. Figure 23 

 demonstrates the preference "Van Halen" (PTT #843) showed for water slightly deeper than 

 the 183 m (100 fathoms) contour which has been noted in the Great South Channel by 

 Winn, et al. (CeTAP 1982). 



Dive Depths 



In 1989, "Van Halen's" (PTT #843) transmitter was equipped with a pressure sensor 

 to describe dive depths. The deepest dive during the 4-hour summary period was recorded 

 and indicated dives to, or near, the bottom during most of the periods for which there were 

 locations (Figure 25). Thus, it appears that some right whales routinely sample the water 

 column from surface to bottom. As noted previously, right whales are observed in the Bay 

 of Fundy surfacing in water exceeding 200 m with mud on their rostrum (S. Kraus, pers. 

 comm.). Maximum dive depths of 272 - 306 m were recorded for "Van Halen" (PTT #843). 

 A closer examination reveals two areas where dives did not appear to reach the bottom. 

 One area, early in the records, was on the banks where surface breeding activity is often 

 observed. The other, late in the record, was over a 180 m slope east of Jeffrey's Ledge 

 where upwelling is common and the whale may not have needed to go to the bottom to find 

 food. Right whales may have a preference for slope areas like the one east of Jeffrey's 

 Ledge to take advantage of diel migrating copepods coming up from deeper water (Winn, 

 et al., 1986). 



Though there is evidence that right whales may routinely dive to the bottom of their 

 habitat, we only have the discrete dive depths reported for one whale in 1989. This showed 

 that most of the dives greater than 2 minutes were less than 68 m (Figure 26). The 

 summary information showed that the deepest dive in a 4-hour period was most commonly 

 136 - 170 m (Figure 27). The deepest depths recorded for "Van Halen" occurred after 

 sunrise (Period 3) and the shallowest average maximum depths were around sunset. The 

 latter would coincide with the rise of the deep scattering layer when the average maximum 

 depth of dive was 125 m. 



Speeds 



Using Argos locations, we calculated the linear distance between two points as the 

 distance traveled, when in fact the whales may have traveled a much greater distance. Thus, 

 the calculated distances and speeds reported here are minimal. In addition, location errors 

 were not taken into consideration, and may have greatly affected estimated distances and 

 speeds. A frequency histogram of the traveling speeds for all 1990 tagged whales is shown 

 in Figure 28 and is further separated by periods of the day. Speeds of 2 - 3 km/hr were 

 most common and speeds in excess of 7 km/hr were uncommon. There were more slow 

 swimming speeds (averaging from - 3 km/hr) between midnight and noon (Periods 2 and 

 3) than between noon and midnight (Periods 1 and 4). High speeds (above 10 km/hr) 



48 



