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Shark Bytes

May 2003 Shark Bytes

written by Monique Fallows

Posted on Saturday, 31 May 2003

Hello Shark Byte Readers!

 

May has been a surprising month with both highs and lows!

When I say highs, I am referring to our pelagic trips with the Mako and Blue sharks. In the two previous seasons of us conducting these trips we have not been out into the deep past the month of April. As a general rule there is supposed to far less tuna around, the water temperatures cooler and the warm water much further from the coast. Despite these factors we had some of our best experiences of the whole season, diving with Mako’s on all but one trip. But, the most exciting experience happened on one of the best weather days we have had out in the deep pelagic currents.

There was no swell and there was no wind, pretty good factors for an enjoyable day! Sometimes when the weather is this good we find that the sharks can be quiet slow. After an hour of waiting we had a small blue shark come up to our bait. We all got in the water with him even though he was a touch shy, going away for a few minutes at a time and then returning for a short while. He eventually tired of us and left us waiting! Just when things seemed really quiet, Chris saw a silver flash behind the boat…now that usually means only one thing, Yellow-fin tuna! On a very few occasions we have seen a few shoals fly by while we are in the water, but what we were about to experience was something we would have never have expected to happen.

On seeing this silver flash Chris threw a few pieces of sardine on the surface. An explosion of water followed as the yellow-fin launched at the sardine and broke the water. After throwing a few more chunks of sardine the rest of the shoal started to follow suit. The sea in front of us become a swirling mass, as the surface water broke while the tuna competed for the bait. We estimated them to be moving at speeds of up to 30 kmph .The scene was mind-boggling! I had just climbed out the water after being with the blue shark and in my excitement I grabbed my mask and snorkel and jumped in the water. I didn’t even have my weight belt or fins and was hanging on the dive step! When I looked beneath the water the scene was of about 40 extremely large tuna fighting for the tidbits and rushing in at enormous speeds. I remember screaming with excitement every time one would rush up to me. While everyone scrambled to get wetsuits on, Chris was throwing little bits of sardine no less than 40 cm from my mask! I would just see the sardine for a few moments before the beautiful fish with its elongated yellow sickles would approach like a bullet train. Now these tuna can get extremely large and we thought that the fish we were in the water with were in the region of 50kgs to 90kgs (roughly 100 to 200 pounds). I think that if one of these guys were to collide with us it would be pretty painful to say the least! I was surprised to observe that at anytime the sardine bit was too close to us the tuna would steer clear of us.

The tuna stayed around our boat for about two hours until our whole sardine supply was eaten. I can truly say that it was one of the most exciting events I have ever witnessed. Not only is the speed and power and maneuverability of this fish so impressive, but it’s beauty also left us captivated with it’s silver and blue surface etched with bright yellow fins and elongated yellow sickles allowing it to move as it does. 

At some point the blue shark returned, but was dominated by the tuna. A full grown female seal also arrived and tried catching the tuna. Although seals are extremely fast we could see that the tuna were basically playing with her and were under no threat at all.

That whole night I kept dreaming that we were still with them! I certainly do dream that we will one day again have that same experience!

 

May also signifies the return of the great whites to Seal Island in False Bay. I just want to explain to the many readers who may have joined in our white shark off-season what Seal Island is all about.

Seal Island is a cape-fur seal colony home to 64 000 seals. In our winter months (May until September) the water temperatures decrease from 21 degrees (Celsius) in summer to 12/15 degrees in winter. As the water cools down, the Migratory Summer fish leave False Bay in search of warmer water up our East coast. The white sharks prefer to feed on the fish as seals can potentially injure them as they scratch and bite their hunter. If a white shark looses an eye it will be unable to hunt which is why they prefer to feed on fish,

Of course, in winter they have no choice and have to come to Seal Island to feed. Seal Island is now very famous for the hunting technique known as breaching. The sharks will attack the seals as they swim on the surface, launching themselves out of the water.

Although white sharks have been known to breach at other areas in the world, it happens most frequently at Seal Island.

The area is thought to be a “perfect hunting ground”, as there are steep drop-off’s where seals leave and return from feeding. This enables the white sharks to patrol undetected. Over the last 8 years that we have been running expeditions to Seal Island we have recorded all data from predatory events witnessed and have found the sharks to be successful in hunting seals 48% of the time. This makes the white shark one of the most efficient hunters in the animal kingdom.

This last month has been slow compared to previous years as far as predatory events are concerned. We have only recorded a handful of attacks. When we anchor and wait for the sharks to approach our bait we have recorded a lot of sharks in the area. So, we are pretty sure that soon they will start feeding on the seals.

You will all no doubt be filled in next month as to what is happening around Seal Island!

 

Until then…

 

Fair winds and calm seas,

Monique

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