1999 

 OUR LIVING OCEANS 



Atlantic spotted dolphin- 



stenophagous on zooplanktor,, notably topepods 

 (Mayo and Mant, 1989). Individual animals can 

 be identified from photographs of the pattern of 

 callosities on the head, and from prominent scar- 

 ring (Kraus et al., 1986a). 



The western North Atlantic population has 

 been the subject of a long-term study since the 

 1970's, and much of its biology and behavior is 

 reasonably well understood (see Kraus et al., 

 1986b; Kenney et al., 1994; Knowlton et al., 

 1994). Most of the population has been biopsy 

 sampled, and genetic analyses are ongoing (Schaeft 

 et al., 1993, 1997; Brown et al., 1994). There is 

 no ongoing field research on this species in the 

 eastern North Atlantic. 



Population Size 



Based upon photographs of identified individu- 

 als, studies indicate that the present western North 

 Atlantic population numbers fewer than 300 ani- 

 mals (Knowlton et al., 1994). The size of the east- 

 ern North Atlantic stock is unknown, but is clearly 

 extremely small. It is assumed that the census of 

 identified whales in the western North Atlantic in 

 1992 represents a minimum population size esti- 



mate (295 individuals). The minimum size of the 

 eastern stock, based on rare sightings, is assumed to 

 be a handful of individuals (perhaps fewer than 20). 



Current Population Size 



No sustained growth is .ippaiciu despite six 

 decades of protection, although the initial post- 

 whaling size of this stock in 193S is unknown. 



Status of Stock 



The northern right whale is critically endan- 

 gered throughout its range (Brownell et al., 1986; 

 Clapham et al.. In press). Cjiiven the various prob- 

 lems described below, this species is arguably the 

 most threatened of all baleen whales, and further 

 conservation action is urgently required to avoid 

 its extinction. 



In the North Atlantic, the eastern stock ap- 

 pears to be essentially extinct; it is likely that much 

 of the then-extant popul.itioii was wiped out by 

 Norwegian whaling at the turn of the century 

 (Collett, 1909). Rare sightings are made of single 

 individuals in European waters (Brown, 1986), but 

 it is not clear whether these represent a tiny rem- 

 nant population or individuals who have wandered 

 in from the west. Nineteenth-century whaling oc- 

 curred at Centra Bay on the coast of West Africa 

 (Reeves and Mitchell, 1 986), raising the hope that 

 this area may still be a breeding ground for any 

 remaining eastern North Atlantic animals. A sur- 

 vey in this region in earlv 1996 failed to find a 

 single whale, although survey conditions were ex- 

 tremely poor. 



Analyses based upon photographs of identi- 

 fied individuals indicate that the present western 

 North Atlantic population numbers fewer than 

 300 animals (Knowlton et al., 1994); given that 

 the majority of the popul.ition appears to have been 

 identified, this is likely to represent one of the more 

 accurate estimates of abundance for any large 

 whale. 



Unfortunately, the right whale appears to suf- 

 fer from anthropogenic mortalities more than any 

 other. In the western North Atlantic, entanglement 

 in fishing gear and ship strikes are known to have 

 caused several right whale deaths in recent years, 

 undoubtedly contributing to the apparent failure 



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