A closer look at the Bronze Whaler shark
No two shark species are the same with a wide variety in the physical characteristics that are observed with each. The Bronze Whaler shark, whilst sometimes hard to distinguish from other whaler species, like the Dusky shark Carcharhinus obscurus, is characterised by some unique features as outlined below along within an overview of the species appearance.
Size: Bronze Whaler sharks are thought to be able to grow up to lengths of approximately 3.5 meters in length (Last and Stevens 2009) and 305 kilograms in weight (maximum weight of 304.6kgs recorded by IFGA 2001).
Body shape: A classically shaped requiem species, that is to say, torpedo-shaped with a slender body, the Bronze Whaler has a long moderately rounded broad snout. The pectoral fins are large, pointed and falcate or sickle-shaped, the first dorsal is medium sized with a pointed tip and the second dorsal is small and low. There is no ridge between the two dorsal fins, a feature that is seen in the Dusky shark and the lack of such in the Bronze Whaler allows for distinguishing between the two species on closer inspection (Compagno et al. 2005). The caudal fin or tail is heterocercal, that is to say one lope is larger than the other and with Bronze Whaler sharks the tail’s upper lobe is 2-3 times longer than the lower lobe.
Colouration: The common name of this species does hint towards its’ colouring. The Bronze Whaler shark displays dorsal surface colours of bronze-grey to olive-green and white on its ventral surface, the pelvic and pectoral fins are tipped with bronze to black edges.
Eyes: Its all in the eyes! Bronze Whale sharks have relatively large, circular shaped eyes with an iris light golden green in colour and dark slit pupils. This species utilised an eyelid structure called a nictitating membrane, a thin, tough membrane that protects the eye from injuries by predator or prey.
Teeth: Last but not least, the teeth. The Bronze Whaler shark is thought to have approximately 63-65 functional teeth which are narrow, triangular and outwardly hook-shaped, like other species of shark they have numerous rows of teeth with the replacements developing behind the functional teeth. Sexual dimorphism is seen in the upper teeth, in which the males have more proportionally longer and hooked teeth than the females and juveniles. The distinctive upper teeth are one of the distinguishing features between this species and others of the Carcharhinus genus.
Compagno, L., Dando, M. & Fowler, S. 2005 A Field Guide to the Sharks of the World. Harper Collins Publishers Ltd, London, United Kingdom.
IFGA: International Game Fish Association
Last, P.R. and Stevens, J.D. 2009. Sharks and Rays of Australia. Second Edition. CSIRO Publishing , Collingwood, Australia.