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Shark Bytes

January 2005 Shark Bytes

written by Monique Fallows

Posted on Monday, 31 January 2005

I Hope that everyone’s year has gotten off to a good start. We have had a very good month for sharks and other species, seeing a variety of marine life.

 

The middle of the January brought very good conditions for shark and ray bycatch in the treknets. We fortunately had two very capable volunteers helping us to tag and release the sharks and rays and the two extra pairs of hands made a huge difference in getting the animals back into the sea as quick as possible. There were actually only a total of 3 bronze whaler sharks but plenty of very large Duck bill rays, Diamond rays, and bull rays. In the last five years I have only seen a handful of Duck bill rays, but over a period of about four days the conditions to find them must have been perfect. In one net there were a total of 9, and most of them were all large pregnant females. In fact when we were pulling them back into the water we could see the pups wriggling around inside their mothers…it was quite a sight. Unfortunately in the trek where the most number of Duck bills were caught the net was full of kelp and other waste. This made the net very difficult to bring in and the rays were left in the net for a long time. As we were worried about them we decided to take them straight back into the water rather than measuring and tagging them which would have taken some time. One of the pregnant females was so stressed that that she aborted her pups while in the net. Luckily they were full term and we were able to release both the mother and pups giving them the best chance possible.

 

These rays are particularly large and the ones we were releasing were in the 60kg to 80kg range. (120 pounds to 160 pounds). The way we release most rays is to drag them back into the water by putting our hands inside their mouths to grip them. They have “pavement teeth” which are used for crushing their prey and these “teeth” cannot actually cut you. One of the Duck bills was so large that she was too heavy for one person to drag back into the water so Chris & I had to do a team effort. We wished we could have measured her as we are sure she would have been one of the largest rays caught in the beach seine nets!

 

We did manage a new record though with a Diamond ray that was caught in another net on the same day. This ray measured 1,73 meters across its disc. The largest previous caught Diamond ray was 1,65 meters and this was way back in February 1995. It was really exciting for us to see such a large animal that has survived under today’s pressures. In the excitement we had forgotten to tell one of the volunteers who was releasing her that Diamond rays have different dental impressions and actually have teeth! He soon found out about this when the ray would not let go of his fingers. After a lot of tugging the ray eventually let go but in the process left Shamus with some nice memento scars!

This ray measured 1,73 meters across its disc.

Around this time we decided to take an impromptu trip up the Cape coast to look for smooth hammerheads. While we were away the treknetters caught eight bronze whaler sharks in one net. They thankfully released all of them, and the positive outcome is that they are now asking for a tagging kit so that they can tag the sharks when we are not there. This is fantastic progress seeing that in the past all sharks were killed for their meat and fins.

 

Our trip up the coast was a little disappointing due to bad weather and we were only able to go to sea for one afternoon. On this trip we saw a large number of smooth hammerhead pups (probably about 40 in total) and also attracted about the same number of bronze whaler sharks to the boat. They were also mostly smaller than average bronzies, but we also saw one or two much larger ones.

 

We have a 7 day trip planned up there in March as part of our Sharks of Southern Africa Expedition and are really looking forward to diving with them again.

 

We have also been able to undertake quite a few pelagic shark trips. Although we are primarily looking for mako and blue sharks we are always on the lookout for the large variety of cetacean species that can be found off Cape Point in the Agulhas current. On one of the trips Chris spotted a large pod of about 40 Risso’s dolphins. This is only the third time we have seen them out here and we had by far our best ever interaction with them. They are large dolphins that can grow to 3,8 meters. These squid feeders have a life span of 30 years and all of them have extensive scarring concentrated on their back and sides. These scars are believed to be made by the teeth of other Risso’s dolphins as well as by the squid that they prey on. The open ocean water was particularly blue on this trip and although they did not ride the bow of the boat we were able to watch them through the blue water as they cruised a little way off us. Chris and one of the guests actually jumped over board with them and had a mother and calf approach them. It must have been a fantastic experience and I must say that I was a little bummed that I was left to skipper the boat!

 

All the pelagic trips we have done in the last week have been a little unusual as the water has been a very dirty green colour, much colder than normal and there have been no tuna around. We have amazingly seen a lot of sharks, particularly blue sharks. On the last three trips we have had at least 10 blue sharks on each trip and on the last trip we briefly had a very nice mako. I have not seen a mako since late May last year so I was thrilled to see one again. But my highlight of the month was on our last trip where we saw a Bigeye thresher shark jump. I was sitting at the front of the boat and was looking in exactly the right spot at the right time as the thresher did a spectacular breach. As I shouted in excitement everyone else on the boat turned to look and the thresher breached again. It is not uncommon to find Bigeye and common threshers off Cape Point but as they are mid-water column sharks, as well as being timid sharks they are not often seen. We have never had one approach a bait at the boat, but we always wait in hope!

 

Lastly I feel I need to write about a disturbing incident. A friend telephoned to say that he had just heard a report that live shark carcasses had been dumped at Gordon’s Bay Harbor, about 45 minutes from where we live.   To dump a shark carcass is illegal in South Africa so we raced over there expecting the worst. It turned out to be about 30 shark heads consisting of mostly smooth hound sharks, 3 bronze whalers and one large spotted gully shark. It is illegal to dump anything in a harbor but it is unlikely that anything will be done about it. The tragedy is that all of these sharks were pups and probably yield about 6 US Dollars per shark. Most of the mature smooth hound sharks have been fished out and the immature sharks are not given a chance to reach maturity. Although it is legal to catch these sharks it seems such a waste that so little money is gained from it and a shark had to die for this. The spotted gully shark was a very large shark and we have since discovered that a shark this size would be about 25 years old. They are a protected species, but as mentioned before nothing is likely to come of it. Chris & I do have a fantastic life sharing our passion for sharks, but when working with sharks there are far too many sad stories going around.

 

These sharks would not only be sold for their fins but for their meat too. A lot of people eat shark meat and probably do not realize it. Shark is commonly sold as White fish, Flake and Butter fish. Many Fish & Chip shops deep fry shark meat in a batter, especially in Australia where Wobbegong shark is used. I hope that less people will eat shark meat if they know what they were eating.

 

On “Photo’s of the Month” we unfortunately do not have any new images of blue sharks as the water has been too dirty, but there are a lot of interesting images from the treknets. I am sure you would all like to see what a Duck bill ray looks like!

 

Until next month,

Best wishes

 Monique Fallows

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