FISHERY BULLETIN: VOL. 75. NO. 1 



Some breaths were released underwater both in 

 the lagoons and out, and by both adults and young, 

 usually causing a strong boil. 



The gray whale spout is obviously double if 

 viewed in front or behind the whale and may 

 appear single from the side. It varies from a low 

 "mushy spout" in breezy conditions to a fairly 

 slender column perhaps as much as 2.5 m high in 

 very calm air. 



The spout is dense throughout its height from its 

 initial exit point at the animal's nostrils to the top 

 of the blow, and one can occasionally see the col- 

 umn of rushing air "tear" at the surrounding 

 seawater entraining it into the blow as a ragged 

 sheet. Most times the blow seemed to start just as 

 the animal's nostrils rose to the surface and such 

 adjacent seawater was obviously a considerable 

 part of the blow. Occasionally, however, a floating 

 animal did not sink down before a blow and a spout 

 was sometimes not produced. It is our impression 

 that in the calving lagoon most or all of the spout 

 involved either water entrained in the column of 

 rushing air from the sides as the animal's nostrils 

 broke water or from a small amount of water 

 pooled on nostrils, or perhaps more likely from the 

 seawater that had entered the uppermost part of 

 the nostrils just prior to the blow. Condensation is 

 clearly an important part of the blow of whales 

 breathing into cold air, as in more polar latitudes, 

 but was not in our observations within calving 

 lagoons. Neither whales that did not submerge 

 between blows nor stranded calves spouted. 



While spouts were taller and more evident in 

 calm morning air, they were present throughout 

 the day and at sea. Our impression is that visibil- 

 ity is affected by such changing conditions but that 



the mechanism of spout production in this latitude 

 (25°N) remains the same. That is to say, wind may 

 shorten the spout and make it harder to see but 

 most respirations at sea produce spouts regardless 

 of time of day. 



Baby whales during swimming tend to toss their 

 heads upwards when they blow, unlike adults, and 

 as a result respiration breaks the smooth course of 

 their swimming. This movement is extreme 

 enough that one can sometimes see their lower 

 jaws rise free of the water during respiration. 

 Adults always seem to remain more deeply 

 submerged with eyes and lower jaws well below 

 the surface during spouting. 



Patterns of respiration are quite different in 

 mothers and young. One young animal observed 

 moving slowly with an adult took 88 breaths/h 

 while the attending adult took 58 breaths/h (Fig- 

 ure 6). 



During what we suspect might be nursing 

 sequences by an instrumented calf, surface times 

 were considerably longer than otherwise, av- 

 eraging 16 s/min as opposed to 3 s/min in travel- 

 ling young. 



During steady swimming the respiratory pat- 

 tern becomes more regular, generally with a 

 sequence of closely spaced blows followed by a 

 longer period of apnea, with this sequence re- 

 peated over and over (Figure 2) (see also Wyrick 

 1954). 



Often, adult whales were encountered floating 

 absolutely passively in the calving lagoon. The 

 back from about the nostrils to the base of the tail 

 was often exposed. In such instances we were 

 impressed by the very broad curve of the exposed 

 back, as if the chest of the animal had a huge 



Mother 

 Calf 



Mother 

 Calf 







10 15 20 



Time (minutes) 



25 



30 



FIGURE 6. — Respiratory patterns of a California gray whale mother and calf pair swimming slowly off Colina Coyote, Baja California 

 Sur, Mexico. Adult respirations equal 58/h; calf 88/h. Note that while initial respirations of a breathing sequence were sometimes 

 simultaneous indicating surfacing together, often the calf surfaced first while the adult swam out of sight below the calf. 



168 



