Bronze Whaler Sharks at Dyer Island, Gansbaai South Africa
November 14, 2013 by dyertrust
With the recent sightings of Bronze Whaler Sharks around our tourism partner, Marine Dynamics Shark Tours, cage diving vessel - Slashfin, the intrigues of this species has caused us to look at their distribution, habitat and behaviour more closely to try and understand why they are visiting these boats.
One fact worth mentioning is the temperature of the water the last few days in this area, varying from 17 to 18.5C. Maybe this combined with the abundance of small pelagic fish, also spending time around the boats, might have caused these sharks to come inshore.
Watch the video about this here
Bronze Whalers Carcharhinus brachyurus, often referred to as copper sharks or Bronzies, were first described in 1870 by Albert Gnter a British Zoologist. The nick- name whaler was given to a number of large bodied shark species in the 19th century associated with scavenging carcasses at whaling fleets in the Pacific ocean. Although they are similar in appearance to the Dusky shark (C.obscurus) they can be distinguished apart by the shape of the upper teeth, the absent or weak dorsal ridge and their bronze coloration. They are one of the few requiem sharks known to inhabit temperate waters (above 12 Celcius). (Figure 1).
Bronze whalers grow to a maximum total length of 3.3m (TL), the heaviest specimen on record weighed in at 305 kgs. Sexual maturity occurs late, at approximately 13-19 years old, with total body lengths (TL) of 2.0 and 2.5m in males and females respectively. The shark species is very popular to dive with during the sardine run off Kwazulu-Natal and the Eastern Cape, where they aggregate to feed on the annual migration of South African pilchard (Sardinops sagax) which is subsequently considered the most important prey item for C. brachyurus in SA waters.
Female and male life expectancy is 25 and 30 years respectively. Breeding occurs during spring and summer months, particularly October and November, in the Southern Hemisphere.
This was a first time sighting of Bronze Whalers swimming alongside Great White Sharks around Marine Dynamicss cage diving boat, Slashfin, they have however experienced small Hammerhead Sharks and Skates visiting the dives before.
For more info on Marine Dynamics please visit their website here