Just a quick vid, showing some diving we did off Cape Point.

Enjoy

Its all very well getting in the water sharks, but its important to understand what they are and who they are. Here is some information gleaned from the web and scientific papers about our Sevengill Cowsharks as well this family of sharks.

What is a Cowshark?

Cow sharks, or the Hexanchidae, are a family of sharks characterized by extra pairs of gill slits. There are probably only two seven-gilled genera, Heptranchias and Notoryhncus

Cow sharks are considered the most primitive of all the sharks, because their skeletons resemble those of ancient extinct forms, with few modern adaptations. Their excretory and digestive systems are also unspecialised, suggesting that they may resemble those of primitive shark ancestors. Their most distinctive feature, however, is the presence of a sixth and, in two genera, a seventh, gill slit, in addition to the five found in all other sharks.Cow sharks are ovoviviparous, with the mother retaining the egg-cases in her body until they hatch.

There are just four species of cow shark, in three genera

• Genera Heptranchias
  • Sharpnose Sevengill shark Heptranchias perlo
• 
• Genera Hexanchus
  • Bluntnose sixgill shark, Hexanchus griseus
  • 
  • Bigeye sixgill shark, Hexanchus nakamurai
  • 
    
• Genera Notorynchus
  • Broadnose sevengill shark, “Notorynchus cepedianus
  • 

    Jean Tresfon

The Broadnose Sevengill Cowshark, Notorynchus cepedianus

This is the Cowshark we find along our coastline and the specie dived with at Millers point. It is called a number of names Cowshark, Sevengill shark or the full length Broadnose Sevengill cowshark, which has one too many descriptive nouns for my liking. We mostly just refer to them as Cows ! Not a very frightening name to attract shark divers. This shark is the only existing member of the genus Notorynchus, in the family Hexanchidae.

What does it look like?

The Sevengill Cowshark is gray or brownish with spots. It is very common in the kelp forests around the Cape. It is easily distinguished from the other common kelp dwelling species, the spotted gully shark, by its lack of dorsal fin and rounded head.

Steve Benjamin swimming with a Sevengill Cowshark by Jean Tresfon

Sevengill Cowsharks can be found on the continental shelf, often in shallow water. Occuring very close inshore, in bays and estuaries, with larger individuals ranging into deeper waters offshore and deep channels in bays. In tropical to temperate waters; except North Atlantic and Mediterranean Sea. Southwest Atlantic: southern Brazil to northern Argentina. Southeast Atlantic: Namibia to East London, South Africa. Western Pacific: southern Japan to New Zealand. Eastern Pacific: British Columbia, Canada to Chile. Record from India maybe erroneous.

Distribution map of the Sevengill Cowshark

What do Sevengill Cowsarks eat?

The sevengill shark, Notorynchus cepedianus, is a versatile and common predator that has often been overlooked as an important marine predator capable of feeding on a wide variety of prey species. Stomach content analyses were performed on specimens from California, USA, and southern Africa to investigate whether dietary differences occur in relation to sex and size. Of the 531 specimens examined, 365 (68.7%) contained prey items. The dietary trend with growth and maturity shifted from fish to sharks (chondrichthyans), with marine mammals becoming increasingly important in the larger size classes of N. cepedianus . Small N. cepedianus (<120 cm total length, TL) fed primarily on teleosts, whereas larger sharks primarily consumed chondrichthyans. Marine mammals made up about one-third of the diet of N. cepedianus >220 cm TL, while teleosts declined to 6% and 13% for male and female sharks, respectively. A decrease was observed in the dietary overlap of each successively larger size class. Ontogenetic changes in the diet of N. cepedianus may provide insight into understanding how adults enhance the survivorship of their young, who are often less experienced at foraging for prey and are more vulnerable to predation.

Sevengill Cowshark tooth

When are Sevengill Cowsharks sexually mature ?

Maturation in male sevengills begins at about 140 cm total length (TL). Most males mature at approximately 160 cm TL. Male sevengills have viable sperm throughout the year and seem capable of reproducing year-round. Females have a complex and prolonged maturation period and mature at a size in excess of 218 cm TL.

What are the threats to Sevengill Cowsharks?

In south africa these sharks are caught as part of the demersal shark fishery as well as a species targeted by recreational fishermen. Cowsharks are not protected and anyone can capture and kill a shark as long as its not in a marine reserve. These sharks are sometimes used as bait in the White shark industry.

In South Africa Cowsharks are the apex predator in their habitat, and once the reach maturity only a great white shark or Ocra would prey on them. The following is an abstract details such an attatck by Orca’s in Argintina.

On 21 December 1998, four killer whales (an adult male, two females or immature males, and one juvenile) attacked a group of sevengill sharks (Notorhynchus cepedianus) off the coast of Caleta Malaspina, Chubut, Argentina. Persecution, catches, and tossing behavior were performed by the two females or immature males in the inlet. Next day, carcasses of several sharks were found on the beach adjacent to the attack area. Seven of them were intact and sized approximately 2.5 m in length. The presence of complete sevengill shark carcasses on the beach suggests that they were attempting to avoid capture by the killer whales by stranding on the beach. Attacks on sevengills by killer whales in Caleta Malaspina are frequent in some years, especially from mid-December to mid-January when the sevengill seems to use the inlet as a nursery ground. The observation of the same male feeding both on pinnipeds in Peninsula Valdes and on sharks in Caleta Malaspina may indicate that at least some groups in the Southwestern Atlantic could regularly feed on both fish and marine mammals. This is the first report of an attack of killer whales on sharks off the coast of Patagonia, and the first report of toss- ing behavior in sharks.

Where  can I dive with these sharks?

The best place to dive with these sharks is in Castle Rock Marine reserve at  Miller’s point, Cape Town. This part of the peninsula coastline is below the Swartkopberge mountains. The small rocky peninsula of Miller’s Point juts out rather abruptly into the bay and provides a sheltered site for the slipway from which most of the boat launches in this area are made. There is sufficient reasonably level ground for extensive parking areas off the main road, including boat trailer parking.

Map to the Cowsharks of Cape peninsular, Cape Town

This area is characterized by granite reefs with sandy patches between them, and almost flat sand bottom further out. Many of the reefs are fairly large areas of massive ridges, gullies and occasional loose boulders on top, and some of these boulders are huge. The cowsharks stick to the kelp channel just 50m from the shore. One can shore dive or boat dive this site (Source)

Jean Tresfon

When can I dive with these sharks ?

There sharks are present year round with the best periods being Spring and Autumn. The best vis is during winter but storms can make conditions undivable for long periods. During summer there are many sharks but the strong trade winds make the visibility quite poor. Due to the relatively protection of the site it is divable most days of the year. We have had great shark dives in vis as low as 2m !

Water temperature during winter is usually between 13°C and 17°C, though it has been known to drop as low as 11°C, so a good suit is also needed here. In summer the temperature may rise above 20°C, but is more likely to be around 17°C to 19°C. (Source)

What should I do while diving with Sevengill Cowsharks ?

Sevengill Cowsharks, although generally docile, are large predatory animals capable of inflicting bodily harm to humans if provoked. Therefore a strict code of conduct must be adhered to when diving with the sharks.

• – No touching.
• – Divers should not interrupt swimming patterns of the sharks
• – Avoid boxing in of a shark,  between two divers, or between a diver and a rocky outcrop.
• – No bait or chum is to be used when diving with the sharks.
• – Buoyancy control – you may get in a shark way or bump into a shark if you cant yet dive correctly.

Jean Tresfon

I put this short film together after a great days diving. We spent the day looking for yellowtail (Seriola lalandii) and I manage to film and shoot a fish. There were alot of ragged tooth sharks on the reef and one came up to try eat my yellowtail, which was nice to capture on film.They are only interested in the fish and can be easily pushed away.

Please have a look, the film speaks for it’s self ……………….

If you liked it, please let me know and PASS IT ON ……. I want to make some more of these

Cheers

Steve

I put this short video together to try show you what diving in Cape Town can be about. I also wanted to thank all the great people who share my life and passion for life, be it on the water or land. Live life to the fullest everyday…….

Have a look…

We headed out out of Houtbay Harbor in search of Blue sharks. We had a limited window to capture the images we needed and the break in the weather was marginal at best. We traveled West and rode through the rain and fresh winds of the peninsular. We saw a few Tuna poling boats but no trawlers or long liners to make finding sharks and fish easy. The water temperature was suitable, we started chumming and the Blues found us. We ended up with 8 sharks ranging from 50cm to 2,5m in length. There were a few seals in the area which occasionally came in to have a look.

In the video you can see one shark approach and give the camera an inquisitive nibble.

Peter Verhoog was there to capture some images of these amazing sharks

Still image from video as the blue shark approaches

Inside of a blue sharks mouth

A poor image showing seals and blue sharks interacting

This is what Cape Town can be !!!

This is what Jean Tresfon had to say

Following several days of pumping SE winds the water on Cape Town’s Atlantic seaboard on Saturday was looking about as good as it gets: 20m viz and a chilly 10 deg C. A few enthusiastic divers and photographers jumped onto a boat and headed out into the blue to see if we could get some good dolphin interactions. We saw some common dolphins on the hunt but they were not interested in stopping. The dusky dolphins however were a different story and spent almost half an hour with us allowing for a stunning interaction. While in the water a Brydes whale swam under me but I was not quick enough to get a photo. The excitement on board was infectious and we all agreed the day out had been worth it. On the way home some more dolphins appeared and we jumped back into the water. Finning fast and following some of the dolphins I saw a huge cloud of white water ahead and the next moment I was face to face with two 30 ton humpback whales. This was my first time in the water with a really big whale and I was blown away by how big these animals actually are up close. The law in South Africa prohibits approaching closer than 300m to a whale so we swam back to the boat, but not before taking a few photos of course! On the way back we stopped at Seal Island for a quick dip. So one boat ride out and we were able to dive with three different mammals in one afternoon, not too shabby for a day out in the Cape!

Jean Tresfon surrounded

Jean Tresfon and Dusky

Image by Steve Benjamin

By Jean Tresfon

By Jean Tresfon

By Jean Tresfon

By Jean Tresfon

By Jean Tresfon

It was special day on Sunday in False bay, Glassy, great vis and warm. It was a real summers day with the vis of winter. We dived with the Sevengill cow sharks and seals most of the day. There were a lot of fishermen catching snoek nearby, however we didn’t catch anything. The entertainment coming from catching gurnards when someone got a birds nest and the lure stayed on the bottom to long.

It was just one of those days your happy to be alive. Here are a range of images from the day.

Thanks to everyone for the great times

Catshark video clip

It was a glassy beautiful day at Dungeons, with most of the guys out and ready. A handful of great waves came through but the swell didn’t quite live up to expectations.
Jem Johnson jumped off the boat and straight into a great wave. I was caught by surprise so the footage is overexposed but you can have a look.

Check out this great article written by Roosta here

Jem, Jason and Rooster

Jem Johnson by Mark van Coller

In the pouring rain we kitted up for a day of seals and cow sharks. Everyone was keen to get into the clean (15m vis) blue winter waters as it was much more pleasant under than above.

Steve, Tomas, Jenny, Alex, Cara

The team headed to partridge point for some seal snorkeling. It is always amazing to see an animal so happy in the water. The team quickly had seal between their legs and smiles all round.

Next we put on our SCUBA kit and went down to the cow sharks. First we played with the puffadder shysharks and pyjama sharks but it wasn’t long until a cow shark came in to investigate. We explored the caves and overhang’s and found cuttlefish, west coast rock lobster, abalone and giant periwinkles. The magic of the kelp forest can never be underestimated.

Cuttlefish

Great day in False Bay

Cheers

Steve

A beautiful still day in the bay, spring is on the way. I picked up Hanli Prinsloo and Craig McKune and headed to Millers point for an afternoon of Cowshark freediving.

We entered the water and were greeted with 15m vis and 16C water…heaven!!!

I wanted to show the team what a healthy False Bay ecosystem should look like and point out a few fish species. I took them to the thick kelp bed near pyramid rock and by the third dive all the red roman, red steenbras, bankies and red stumpnose had come in from the surrounding areas to investigate the activity. Great to see these fish in the bay, it is near impossible to find them outside these safe areas.

We swam out into the sparse kelp forest that the Cowshark like to frequent and sure enough there they were. We dived on a small area and waited for the sharks to come to us. It is 12m deep in this area and simply by lying still on the bottom they came to investigate. I would guess we saw 10-15 sharks in total and 1 pregnant Spotted Gully shark.

As we headed into the shallows I spotted a puffadder shyshark. I love these sharks and dived to film it. I was getting a close up when a cowshark came from behind and swam straight into my camera and continued on its way, the clip is at the beginningCowshark diving of the video. Just goes to show you never know what can happen next.

Hanli Prinsloo and Cowshark