The fisheries and environment department has confirmed that the carcass of a shark that washed ashore recently in Jeffreys Bay was a great white — and it was likely killed by an orca.
The assessment adds to the continuing debate about the decline or redistribution of SA’s white shark population, and what is driving those different change scenarios.
The species is protected not least because of its stabilising position at the top of the marine food chain, but about a decade ago it started disappearing from its former stronghold off the Western Cape coast.
Today white sharks appear to have vanished completely from that range, and any sighting of the species raises interest in conservation, fishery and ocean activity circles.
Department of forestry, fisheries and environment spokesperson Zolile Nqayi said on Wednesday researchers had examined the photograph taken of the shark, which was washed up on the beach near Die Walskipper restaurant in mid-August.
“The photographic evidence provided is consistent with characteristic orca predation, including liver removal.
“The carcass also appears to have subsequently been scavenged by broadnose sevengill sharks, as indicated by the rounded bite marks and tooth scoring.”
Asked how the incident spoke to the debate about the health of the white shark population, he said the department based its research decisions on “best available evidence”.
“Current scientific evidence does not support a significant decline in the South African white shark population as a whole.
“Rather, there is evidence of changes in distribution, including increased use of areas along the Eastern [Cape] and KwaZulu-Natal coastline.
“There is clear evidence that shark-eating killer whales can affect white shark behaviour and distribution, with white sharks rapidly leaving areas following encounters with orcas.”
He said the orcas with a taste for white shark livers included two particular animals, dubbed Port and Starboard, which first popped up in South African waters in 2012.
The notorious pair were named after the direction in which their dorsal fins flapped over.
Nqayi said it was not clear why the orca attacks on white sharks were emerging only now after millennia of peace between the two mighty marine predators.
“There is insufficient historical information to determine why this relationship has become more prominent now.
“The killer whale distribution and occurrence in SA is currently being studied and should provide more definitive answers in the future.”
He said there was no evidence that the demersal longline fishery for small sharks was triggering the decline of the white shark.
“Approximately 95% of historical effort in this fishery has occurred in the Eastern Cape, while the major changes in white shark occurrence have been documented at Western Cape aggregation sites.
“There is currently no scientific basis to attribute the observed displacement of white sharks to this fishery.”
Nqayi said the white shark had been legally protected in SA since 1991, and the unauthorised removal or possession of parts, including fins and teeth, was illegal under the Marine Living Resources Act and the National Environmental Management Biodiversity Act.
Groups including Gqeberha-based Algoa Bay Conservation and Raggy Charters have argued that a substantial proportion of white shark prey comprises the same little sharks being targeted by SA’s demersal (seabed zone) longline shark fishery, and the big predator is consequently running out of food.
The fishery sells most of its catch to Australia where the little sharks, primarily the critically endangered soupfin and smooth-hound, are processed for the take-away flake and chips market.
Algoa Bay Conservation spokesperson Ronelle Friend said while the fishery might be focusing now on the Eastern Cape, it was operating in the Western Cape when the decline of the white shark began in 2017.
“Regarding orcas — they have been around forever, so why should these attacks be triggering such significant changes in the white shark population now?
“Furthermore, we have orcas up here in Eastern Cape waters too.
“So if they are the culprit, why are they not driving the decline or redistribution of the white shark in these waters?”
She said the occasional white sharks spotted in Algoa Bay were all smaller, younger animals.
“White sharks over 4m are generally not being seen anywhere on the SA coast any more and that’s a concern because those are the breeding adults.”
She said though there had been a particular spike in white shark numbers off Chintsa, north of KuGompo City, these were nothing like the number of white sharks that had disappeared from the Western Cape.
“We believe that the demersal shark longline industry is reducing the food available to the white shark, and that is one of the main reasons for its decline.
“We need the department to stop folding its arms and blaming the orcas and to invest in some definitive studies, including tracking, so we can really see what’s happening.”
