"Sharks v Dolphins" - Accounts, Research, & Info.

[elosha11]

Here's an account of an orca pod hunting sevengill sharks. They took several of the sharks, but one in particular jumped out of the water to escape and was later rescued by the observers. Another shark apparently decided a good offense was the best defense and turned and snapped at an orca attacker. The orca opened its mouth as if to attack but then turned away and broke off its attack, suggesting it thought that particularly feisty shark may have been more trouble than it was worth. Here's the moment the two animals faced each other, jaws agape. Apparently, this was the only shark to escape.



Here's another picture of the orcas rounding up an already wounded sevengill.



Finally, here's the shark that stranded itself to escape the orcas.

i1-news.softpedia-static.com/images/news2/panicked-shark-jumps-on-land-to-escape-pod-of-killer-whales-491334-6.jpg

Here's the article recounting the interaction.

news.softpedia.com/news/panicked-shark-jumps-on-land-to-escape-pod-of-killer-whales-491334.shtml

[elosha11]

Really cool video recording perhaps the first documented false killer whale attack on sharks. Recent hand held drone camera recorded a pod of false killer whales chasing down and eating small shark, probably a juvenile. Given its overall appearance, relatively slow swimming speed and gracile body shape, I'd guess this was a small grey reef shark or oceanic whitetip/blacktip shark. Here's pics and video link.







www.cnn.com/videos/world/2016/05/11/dolphins-chase-shark-australia.seven-network

[elosha11]

Recent video in Nova Scotia of an estimated 2 meter shark attacking a pod of similarly sized porpoises of Nova Scotia. Likely either a mako or great white. It looks more like a mako to me, and makos seem to frequent these waters more than great whites. It's becoming more obvious that sizeable makos are very active predators of dolphins and pinnipeds. Note that the shark does not seem to be concerned about counterattack from the pod members, and that the pod seems to immediately flee the shark attack.

I've also included a pic and article about the event.





www.citynews.ca/2016/08/07/spate-of-shark-sightings-could-signal-uptick-in-maritime-waters-expert/

[elosha11]

Aug. 10, 2016 video. Shark preying on dolphin on San Diego coast. Although the people on board claim it's a great white, the rounded dorsal fin indicate it's a mako, and mako's are much more common in Southern Cal. than great whites.



Here's an associated article.

sdfish.com/saltwater/video-great-white-shark-eating-dolphin/

[elosha11]

Shark predation of dolphin in Melbourne Australia. Judging by the apparent size disparity between the dolphin and the shark's head shape, (see 2:35 of video), I'd say it's most likely a great white. But at one point of the video the shark's fin looks more rounded, like a mako's and at another point it looks more like a great white's fin. So probably a great white, but can't rule out a mako.

[elosha11]

A few videos of shark predation or scavenging on dolphins. The blue sharks eating the dolphin is likely a scavenging event, since the dolphin appears quite a bit larger than the blue shark feeding on it. The other two videos are clearly predation, although it's difficult to tell what exactly is being attacked in the last video. The youtube posters claim it's a shark attack on a dolphin.

[elosha11]

Here's another video of blue sharks eating a common dolphin. The animals are close in size here. I wonder if blue sharks sometimes prey on dolphins? I don't know if it's scavenging or not, I never have really thought of blue sharks as big game predators.

[elosha11]

Orcas preying on sevengill, thresher, and bronze whaler sharks. Note the tail slapping tactic in the last video.

[Ceratodromeus]

Dec 12, 2016 0:44:25 GMT 5 elosha11 said:

Here's another video of blue sharks eating a common dolphin. The animals are close in size here. I wonder if blue sharks sometimes prey on dolphins? I don't know if it's scavenging or not, I never have really thought of blue sharks as big game predators.

I have not read any accounts of blue shark predation on adult dolphins; i know of this overview article in which the remains of dolphins found in blue sharks are attributed to scavenging. Whether this footage displays scavenging or not, it is still pretty good stuff



www.researchgate.net/profile/Michael_Heithaus/publication/228601732_Predator-prey_and_competitive_interactions_between_sharks_Order_Selachii_and_dolphins_suborder_Odontoceti_A_review/links/0912f5113e8f17d7d7000000.pdf

[elosha11]

First video I've known of orcas eating a hammerhead shark, although there have been pictures of such activities. This is off the Galapagos Islands.

[elosha11]

Orcas appear to be regularly preying upon adult great white sharks in South Africa. Last week, three adult sharks, one female of 4.9 meters and two males of 3.6 and 4.5 meters were found washed up with their livers eaten out (and in at least one case also their heart). Orcas are known to be regular inhabitants in these waters and scientists speculate that the loss of their regular prey sources had forced orcas to pursue less common prey, such as large sharks. But one thing is clear, these predations, especially if they continue, represent another huge risk to the great white population in South Africa, which is already at high risk for extinction.

I am starting to believe that orcas may be a serious threat to contribute to the wiping out of many shark species, along with (and probably because of) mankind's harmful activities. With their pod tactics, huge size, formidable intelligence, and predatory apparatus, no shark, not even the great white, stands much of a chance in a confrontation with the pod. The shark's best option seems to be to flee to deeper water and other territory, but that of course puts continued pressure on the endangered species and may further contribute to their loss of habitat, disruption of mating cycles, and further loss of life. Sad but fascinating interaction.

Here are two recent articles with videos and and a few pics of the sharks presumed to be preyed upon by orca pods. Lots of other articles out there as well.

www.mirror.co.uk/news/weird-news/great-white-shark-v-killer-10421577

www.thesun.co.uk/news/3560288/deadly-predators-wage-war-as-great-white-sharks-slaughtered-by-killer-whales-wash-up-on-beaches-with-their-livers-torn-out/

[elosha11]

Here's an article with many more details, pictures, and observations of researchers performing the necropsy on the three sharks. Largest one was 1.1 tons, which is a fairly common size adult, particularly in South Africa, where the adults sharks are generally less robust and lighter than those seen in California, Australia or Guadalupe Island.

www.sharkwatchsa.com/en/blog/category/503/post/2910/deceased_great_white_sharks_necropsies_reveal_the_causes/

[elosha11]

Mako predation on dolphin. Article and video link.

www.grindtv.com/wildlife/angry-mako-shark-attacks-fishing-boat-defense-dolphin-kill-video/

www.facebook.com/fishcabo/videos/1551870424875353/

[elosha11]

Jul 27, 2014 9:51:13 GMT 5 elosha11 said:

Healed shark bite wounds on a false killer whale in Hawaii. From the website www.cascadiaresearch.org/hawaii/july2010.htm



The researcher states with reference to this picture: "False killer whale with recent shark bite wound and a long-term injury to the dorsal fin, August 5, 2010. Photo by Dan McSweeney. This individual is HIPc127 in our catalog, first documented off Maui in March 2000 (with the bent dorsal fin), and seen several times since both off Maui and the island of Hawai‘i. The shark bite wound behind the dorsal fin is the first time we've documented evidence of an attack by a large shark on a false killer whale in Hawai‘i. "

An interesting follow up to the above account re a shark bite on the dorsal side of a false killer whale in Hawaii. This below cited research article documents possible evidence of sharks biting false killer whales in the Caribbean.

"

Among the 71 false killer whales, 18 individuals (25.4%) showed a total of 20 injuries (66.7% dorsal fin, 27.8% body, 5.6% both dorsal fin and body) . .
. . Six individuals (22.2%) had an unidentified injury of which the cause is unknown. These include three individuals that appeared to have crescent-shaped scars on their body which were possibly inflicted by sharks. However, the photographs were of insufficient quality to confirm this. . . . Three false killer whales had injuries that may have been caused by sharks but other causes could not be ruled out. All wounds were located on the dorsal part of the dolphin, which is consistent with other studies [24], [25]. It has been suggested that odontocetes turn their back to the shark when they are attacked or that odontocetes with attacks on their dorsal side are more likely to survive the attack [25]. There are at least ten shark species which are known to predate on cetaceans [25] and six of these occur in the Caribbean, including tiger shark (Galeocerdo cuvier), bull shark (Carcharhinus leucas), sixgill shark (Hexanchus griseus), dusky shark (Carcharhinus obscurus), oceanic white-tipped shark (Carcharhinus longimanus) and mako shark (Isurus oxyrinchus) [63], [64]. It is not known which of these species occur in Aruban waters. In any case, these records indicate that local dolphins may be subject to shark predation.

Research article found at www.ncbi.nlm.nih.gov/pmc/articles/PMC3929637/

If these crescent shaped scars were in fact shark bites, this would bring the total known (to me) incidents of possible shark predation attempts on false killer whales to five.

[elosha11]

Jul 27, 2014 9:37:09 GMT 5 elosha11 said:

Possible great whites' predatory attacks on a pod of pilot whales.

Follow up to this -- in Feb. 2017 a recent mass stranding of pilot whales in New Zealand is thought to perhaps have been caused by a great white shark, and one of the stranded pilot whales exhibited modest sized but very recent shark bites.

The following is a description and quote from a ranger involved in the rescue operation, a recounted in this and a number of other reports.

Bite wounds

DOC ranger Mike Ogle told Radio New Zealand the whales could have been frightened into the shallows by a shark.

One whale had been found with bite wounds and great white sharks were known to be in the area off Farewell Spit, he said.

“There’s one carcass out there with some shark bites in it – but not a big one, just a small one, but quite fresh bites so yeah, there’s something out there.”

www.thejournal.ie/whales-new-zealand-shark-threat-3234262-Feb2017/