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The Great White Life – The Marine Big 5

June 20, 2017

Hello again, I know its been a while we were hit by a huge storm last week and the wifi in the last week was down so I was unable to get this blog to you.

This blog will be talking about the South African Marine Big 5. All of the big 5 are very important in their own way and this will talk about a few quick facts and some conservation issues regarding some of them.

 

Great White Shark (Carcharodon carcharias)

We’ll start off with the main one I came out here to see, up until recently Shark activity has been slow due to the Orca (Orcinus orca) attacks that we had at the beginning of my stay here in SA. But the other day we had the best day in a month and a half, where we had a total of 5 sharks come to the boat with one 2.5m female really working for the clients and us on the boat. She surprised us by coming out of nowhere and lunging at the bait; being successful on more than two attempts.

 

There’s a lot of stigma against chumming for sharks as people seem to believe that chumming draws shark’s closer to beaches, but this isn’t the case with white sharks. White sharks are actually a shallow inshore shark anyway, but the media tries its best to portray white sharks as deep-water hunters that move into shallow water to feed on surfers before going back out into deep-water, which is nonsense. The companies here have been chumming for white sharks for 20 or so years and there’s never been an attack here in Gansbaai.

The reason why it is impossible to condition a white shark like you would with a cat or dog is because these sharks are extremely nomadic in their lifestyle, which means that these sharks never stay in the same spot for very long. The crew estimate that a Shark will only hang around in the bay for about 4-8 weeks before moving off to the next area. This is what makes conditioning white sharks impossible because in order to condition them you need a steady constant population who will remain in the same area year-round.

Also, if white sharks were conditioned they would know to stay in the same place year-round as that is where the food is, but White Sharks need a large number of calories in order to sustain their massive bodies and keep their thermoregulatory (keeping their bodies warm) systems going. When a white shark is able to get the bait, which the crew try their best to avoid, the number of calories that the shark will get is very few as the bait is dead and frozen, it’s the equivalent of me or you eating a cracker.

Cape fur seal (Arctocephalus pusillus)

These are the main food source for the White sharks, cute and cuddly in appearance but just as vicious in their hunting ways as any shark. There are an estimated 64,000 Cape fur seals that live on Dyer Island but this number is from a very old population estimate so chances are that the numbers are a lot higher than that.

 

Due to a high number of commercial fishing, the seals have taken a liking to African penguin, however they don’t eat the whole penguin, they will just eat the stomach as that’s where the fish is.

Cape Fur Seal are very resilient from shark attack and can heal remarkably well, when seals have to feed they make their way out to deep water to feed on fish but on their way out from the island or on their way back in, this is when they are in firing zone of white sharks. If a white shark fails to capture a seal on the initial first lunge, the shark stands a less than 10% chance of catching it. The seals strategy for avoiding being eaten is to hug the sharks tail and keep behind it, they do this because the shark is unable to bite its tail. Mary was telling me about one occurrence where a white shark breached on a seal only just catching it with its bottom teeth, the seal swam to its tail and started mobbing it, the seal then had a second shark come and try to catch it and the seal turned the tables on both sharks and started biting and mobbing the shark before the sharks swam away.

 

African penguin (Spheniscus demersus)

These little guys have had it rough in recent years. African penguins were once plentiful but due to Guano (Bird poo) harvesting, it took away their nesting material which meant they couldn’t make nests as well as they used to be able too. Guano harvesting isn’t as common as it used to be but it still causing an issue today. An increase in Seal populations, which as mentioned earlier kill the penguins to eat their stomachs,  nd an increase in Kelp Gull’s in the area, which eat penguin eggs, is stopping the next generations from being born. A massive decrease in fish stocks is also depleting them of their food source. They are cute but have a hard life in this day and age.

Southern Right whale (Eubalaena australis)

The reason why these Whales are called Right Whales is because back in the old days of whaling these whales were the “Right” whales to hunt. Due to their curious and friendly nature, these whales would literally go right up to whaling boats to have a look and would be harpooned. This lead to a huge decrease in their populations, but in recent years their numbers have made a steady increase. According to a study in 2001 there are now approximately 7,000 individuals, but that number could have increased in the past sixteen years.

Photo credit: Raggy Charters ©

 

The main threats facing these whales are ship strikes, which is where a boat hits them, this is almost always fatal as it causes huge amounts of damage to the internal organs and or bones of the whale. Entanglement in fishing nets or fishing line also causes massive issues for these large animals as it causes drag on their body which would in turn exhaust them and make it difficult for them to surface and breathe and or forage for food.

Southern Right whales here in SA are one of the main sources of tourism, especially in Hermanus which is known as the whale watching capital of the world. In Hermanus they can be so close to shore that you could in theory walk off the shore and swim next to one, although this is illegal. The Walker Bay area, which includes Hermanus, gets closed for 6 months of the year for the whale season to allow peace and quiet for the nursing mothers. The whale season here is between July-November, although they’ve come early this year as I saw them in my first week here back in May. Every year Hermanus has a huge Whale festival which funnily enough never has whales; it’s believed that the whales vanish due the amount of noise that the festival gives off.

Dolphins

During My stay here I’ve been lucky enough to see all 4 of the most common species of Dolphins. These are;

-The Bottlenose Dolphin (Tursiops truncatus)

-The Common Dolphin (Delphinus delphis) In the picture shown.

-The Dusky Dolphin (Lagenorhynchus obscurus)

-The Humpback Dolphin (Sousa spp.).

All but the Humpback are very friendly and curious and will usually ride the bow wave at the front of the boat and can be seen following the boat at the sides.

 

The usual threats here in South Africa are very similar to the Right whale in terms of entanglement in fishing gear or in the shark nets up the east coast. Food depletion and commercial fishing trawlers that catch dolphins as bycatch during their fishing trips are also a factor.

Thank you guys for reading this blog on the Marine Big 5, I hope you enjoyed reading it and I’ll see you guys in the next blog entry.