WATKINS and SCHEVILL: OBSERVATIONS OF RIOHT WHALES 



groups of two to six adults (49% of the sightings), 

 as cow-calf pairs, occasionally in larger aggrega- 

 tions, and in groups including adults and older 

 calves. A wide variety of sizes was seen, from 5 m 

 calves to adults of from 12 m to about 16 m. 

 Calves were apparently born in these waters, 

 since adults observed without calves sometimes 

 were seen a short time later accompanied by 

 small calves. We found no seasonality or geo- 

 graphic factor that could be related to group 

 size. Sometimes new whales replaced individ- 

 uals in groups seen on previous days. 



During winter and early spring, right whales 

 were difficult to observe because they were at the 

 surface for relatively short periods and were eas- 

 ily disturbed. These whales sometimes blew 

 underwater so that no surface blow (spout) was 

 visible, and they did not always raise their flukes 

 above water as they began a dive. In late spring, 

 the whales were found feeding frequently at or 

 near the surface (Watkins and Schevill 1976), 

 and apparently were less disturbed by our pres- 

 ence. Thus, before the middle of April, sightings 

 were usually short encounters, often sufficient 

 only for identification. Later sightings generally 

 were of more leisurely surfacings, allowing 

 longer periods of observation. 



Over the 2 1 yr there were 641 sightings of indi- 

 vidual right whales, with 117 seen on more than 1 

 d during a year (758 total sightings including re- 

 peaters). Some whales were positively recog- 

 nized as repeaters and others were suspected 

 repeaters because of location, sizes, and mark- 

 ings. During the years 1959-66 and 1972-79, 

 approximately equal time was spent on searches 

 during corresponding seasons in likely sighting 

 areas, although the number of whales and the 

 months and number of days of whale sightings 

 varied markedly (Table 1). The large number 

 seen in 1970 was comprised of at least 30 whales 

 close to our ship (for several hours) and two 

 other large groups of at least 20 each a short 

 distance away, totaling between 70 and 100 right 

 whales. Most of our sightings have been in April 

 (57%) and fewer in May (27%), although we 

 usually have searched more than three times as 

 much in May than in April because of improved 

 weather. 



In our usual search, the boat or aircraft first 

 crossed Cape Cod Bay (1-5 times) before round- 

 ing Race Point and searching east and north of 

 Cape Cod, and less often south of Martha's Vine- 

 yard and Nantucket Islands. Right whales were 

 seen most often near the northern tip of Cape Cod 



(Race Point) where movement of water masses 

 collects plankton in nearsurface concentrations 

 (Watkins and Schevill 1976). Otherwise, the 

 whales consistently did not seem to prefer loca- 

 tions within the search area. Right whales were 

 sometimes seen a few hundred meters off the 

 beach, but generally they were several kilo- 

 meters from shore; thus their occurrence cannot 

 be related to bottom topography. No habitual 

 direction of movement was observed. 



Few whales were recognized from one year to 

 the next. Callosity patterns provided good sep- 

 aration of individuals within a small group of 

 whales seen in one year, but often have not been 

 distinctive enough for positive identification of 

 animals from the larger population seen over 

 several years. Many of the callosity patterns 

 were similar, and because of the variability in 

 light coloration (apparently caused mostly by 

 movement of the cyamids), fine distinctions in 

 the patterns have been difficult to separate. The 

 callosity pattern on calves appeared to become 

 more visibly distinct with age, perhaps as more 

 cyamids occupied the growths. Comparison of 

 aerial and boat views of the same callosity shapes 

 shows that the nearly vertical aerial view (Fig. 1) 

 loses small details because of distance, distortion 

 through water, and relative density of cyamids, 

 but it provides a good perspective of the pattern; 

 whereas, the nearly horizontal view of the same 

 whales from a boat (Fig. 2) provides good detail, 

 but generally misses the overall shape. 



The longest sequence of recognition of an indi- 

 vidual right whale was that of a cow seen in 4 con- 

 secutive years, 1973-76. During the first and 

 fourth years, this whale was accompanied by a 

 very small calf. In 1974, the yearling calf still 

 accompanied the cow, and in 1975 the cow was in 

 a group that may have included this calf. In 1976, 

 the cow with a new calf was seen repeatedly 

 throughout 7 wk of observation. The pattern of 

 callosities on this cow was very distinctive, but 

 since 1976 a similar pattern has not been recog- 

 nized. 



Groups of right whales generally were involved 

 in social as well as feeding activity. They some- 

 times broke off from feeding together to chase, 

 splash, and roll against each other, often with 

 three or more whales participating in sexual 

 routines (penises sometimes visible). 



The relative ease of sighting right whales 

 depended on their activity at the surface. The 

 respiration period was variable, often averaging 

 1 blow/min of dive cycle. Dive durations also 



877 



