BRYDE'S WHALE (B) 



Balaenoptera edeni Anderson 1879 



Other Common Names 



None known. 

 Description 



Bryde's whales reach a maximum length of approximately 

 46 feet (14 m). They closely resemble sei whales in external 

 appearance. At a distance, the head of this species is similar 

 in profile and general appearance to that of the sei whale. The 

 most distinctive field characteristic of the species, however, 

 is the presence of three ridges along the head anterior to the 

 blowhole. In addition to the medial ridge characteristic of all 

 the other balaenopterid species, Bryde's whales have two 

 secondary ridges on the top of the head — one along each side 

 even with the blowhole running forward towards the tip of 

 the snout. If they can be examined at close range, Bryde's 

 whales can be positively identified by this character alone. 



The dorsal fin of Bryde's whales is up to 18 inches (45.7 cm) 

 tall, extremely falcate, pointed on the tip, located well more 

 than one-third forward from the tail, and is often irregularly 

 notched or frayed on the rear margin from unknown causes. 

 Bryde's whales are dark gray overall, though some 

 individuals, like some minke whales, have a small region of 

 g^ay on each side just forward of the dorsal fin. 



Natural History Notes 



Bryde's whales, like minke whales, reportedly often 

 approach close to vessels as if curious about them. During this 

 time they may be examined carefully and their identifying 

 characteristics seen. 



Though euphausiids may be an important food for this 

 species in limited areas, Bryde's whales often feed on 

 schooling fish (including pilchards, anchovies, herring, and 

 mackerel). This food preference is reflected in the diving 

 behavior of the species. Bryde's whales are not "skimmer" 

 feeders; they are deeper divers. When they surface to 

 breathe, they often rise more steeply to the surface, exposing 

 much of the head, roll the body sharply, and hump up the tail 

 stock before beginning another dive. In this species, as in the 

 fin whale, it can be generally stated that the amount of the 

 back which is exposed above the surface as the animal sounds 

 is approximately twice the height of the dorsal fin. They 

 apparently do not raise the tail flukes when beginning a dive. 



May Be Confused With 



At sea Bryde's whales may be confused with sei whales, 

 fin whales, and perhaps minke whales. 



They may be most readily distinguished from sei whales 

 by the characteristics discussed on p. 32 and by differences in 



diving behavior. The shallow- feeding sei whales surface and 

 blow at regular intervals over long periods of time. Bryde's 

 whales are deeper divers, less likely to surface, and blow at 

 evenly spaced intervals. If they are seen only briefly or at a 

 distance, however, the two species may be impossible to, 

 differentiate. 



During the winter months, when fin whales may venture 

 into tropical waters, they may also be confused with Bryde's 

 whales. But fin whales seldom exhibit curiosity about boats. 

 In addition, the dorsal fin of the fin whale is larger, is located 

 farther back on the back than that of Bryde's whale, and does 

 not become visible as soon after the blow. It is also less likely 

 to be worn on the rear margin than that of a Bryde's whale. 



The head of the fin whale is more acutely pointed. 

 Furthermore, the right lower lip and the right front baleen of 

 the fin whale are white. The baleen and the right lower lip of 

 Bryde's whales are dark gray. If the animals can be 

 approached closely from the right side, positive identification 

 is possible using these differences in color. 



Like Bryde's whales, minke whales often approach close 

 to vessels. But minke whales have an acutely pointed snout, a 

 single head ridge, and a white band on each flipper. Further, 

 minke whales rarely reach 30 feet (9. 1 m) in maximum length. 



Distribution 



The distribution of Bryde's whales is rather poorly 

 known, no doubt in part, because the species is difficult to 

 positively identify at sea, and records of its occurrence may 

 have often been confused with those of sei whales, fin whales, 

 or minke whales. From stranded animals and confirmed 

 sightings at sea, the species appears to be found primarily 

 near shore in areas of high productivity in tropical or 

 subtropical waters, though it ventures into warmer 

 temperate waters as well. It has been reported from Virginia 

 south into the northeast Gulf of Mexico and the southeast 

 Caribbean, and southern West Indies (Curacao and Granada). 

 To date no migration has been described for the species. 



Stranded Specimens 



Stranded Bryde's whales can be positively identified by 

 the three ridges along the top of the head from the area of the 

 blowhole to the tip of the snout. All other species of 

 balaenopterid whales, except humpback whales have but a 

 single ridge. If the head of a stranded specimen is buried in 

 sand, is decomposed beyond recognition, or is otherwise 

 inaccessible for identification, Bryde's whales can still be 

 distinguished from sei whales by differences in the relative 

 lengths of the ventral grooves (Table 2) and from both the fin 

 whale and the sei whale by differences in the characteristics 

 of the baleen plates (Table 2). 



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