Should the Shark Nets stay?

[Theunis]

A few countries are using shark nets such as South Africa, Australia, etc.

South African shark nets, put in place to protect surfers and holiday-makers, capture between 800 and 2200 sharks per annum and catches are highest in those years when the sardines move close inshore during winter along the KwaZulu-Natal, South Africa coast. More sharks are also caught in these nets during floods due to the fact that the dirty water may prevent sharks from detecting and avoiding the nets.

These nets are basically gill nets, indiscriminately catching harmless species, such as dolphins, skates, rays, whales and whale sharks. Shark nets cause irreparable damage to the eco system and need to be replaced by a more environmentally acceptable method. An electrical repellor (the Pod), may replace the gruesome nets. Due to the harsh nature of our coastline, the technology to supply this device with a reliable power source in the ocean is, unfortunately, still years away.

As far as I know the only shark species that is protected in South Africa is the Great White shark. Ironically, 20 to 50 of this species are caught in South African shark nets each year, probably more than were killed by trophy fishermen before the ban.

What do you think, should the shark nets stay or go?

 

[Timoblue]

sharks are also caught in these nets during floods due to the fact that the dirty water may prevent sharks from detecting and avoiding the nets.

Exactly how a shark detects and avoids a net in the first place is new to me.

As far as I know the only shark species that is protected in South Africa is the Great White shark. Ironically, 20 to 50 of this species are caught in South African shark nets each year, probably more than were killed by trophy fishermen before the ban.

I understand your point Theunis. In the long term and without the nets in place - Would you gladly enter those waters knowing that the nets are not there.

 

[Gen San Chris]

This is a tough one and I do not really know the answer but with nets in place it is said that the beach's are safer for humans but many types of marine creatures are captured and killed in them! I read somewhere that in south Africa they are working on an lectronic barrier which will keep sharks away from the guests as nets do as of now! Lets hope that they can get this new technology working sooner rather than later and give the sharks etc a better chance of survival!

 

[Theunis]

Thanks for your replies Timoblue and Gen San Chris. Shark nets and shark conservation in general are a very debatable issue.

In South Africa a number of drum lines were also installed as a partial replacement of nets.

Drum lines are large drums with baited hooks suspended from them, and are an alternative shark fishing device that not only is more selective than a net in terms of the shark species caught but also is considerably less likely to catch non-shark species.

It is said that the nets have achieved their effect primarily by fishing for those potentially dangerous sharks that come into the immediate vicinity of the protected beaches.

Renowned scientist Dr Leonard Compagno in 1986 "declared that shark nets were no longer required because of the diminishing number of sharks. He said they should have been removed".

It is also said that a high proportion of shark attacks, where there were no shark nets, took place under conditions that were considered unwise for swimming, for instance swimming alone, at night, in dirty water, near river mouths. etc. Avoiding such conditions the incidents of shark encounters will drop.

 

[smellzlikefish]

Quote:
sharks are also caught in these nets during floods due to the fact that the dirty water may prevent sharks from detecting and avoiding the nets.

Exactly how a shark detects and avoids a net in the first place is new to me.

The floods probably draw sharks in by washing things from land down into the ocean. This explains the higher mortality. As for shark nets, I understand the issue, but also think that they serve a purpose.

At the moment, we don't have the technology to implement safer alternatives. I imagine that the nets have a very localized effect, leaving many of the long range ocean cruisers that almost never come close to shore. So while the numbers sound staggering, they are probably spread across multiple, mostly inshore species that have sustainable populations elsewhere. As divers we are biased toward leaving the ecosystems alone because we want to see them, but it is important to understand that the rest of the world doesn't necessarily share our opinion, so we will have to make compromises.

As far as the quote from Dr. Compagno, he is a famous, well written shark researcher, of course he is going to jump to the side of the sharks. He may be a doctor, but even doctors have their biases.

 

[Theunis]

Thanks for your comments smellzlikefish!

Herewith one of many articles I have found on the eyesight of sharks.

"EYESIGHT
Sharks have good eyesight; they have color vision. Shark eyes have a large, spherical lens, a cornea, a retina (with both rods and cones), an iris, and a pupil. They even have good vision in dim light. Sharks, like cats who also see well in dim light, have a mirror-like layer in the back of the eye, the tapetum lucidum. This layer doubles the intensity of incoming light, enhancing light sensitivity. Unlike other fish, shark's pupils can dilate and contract to control the amount of incoming light. The retina has a greater proportion of rods (light intensity sensors) than cones (color sensors), so sharks are very sensitive to small differences in light intensity (dark versus light)".


Some articles even state that a shark's eyesight is 7 to 10 times better than a human's eyesight.

 

[Jupiter31]

Difficult question - one of the issues that has multiple sides, and many valid points regardless of your personal stand.

I think technology is the solution, because its valid for beach goers to want protection (or the appearance of protection!) and they are unlikely to vote/support the taking down of the shark nets without a damn good replacement!

Interesting; here in S FL - off Key Biscayne - I've flown over the beach numerous times in a helicopter and seen lots of sharks close to the beach - mostly carib. reef sharks.

Never been an attack in that area, however if most beach goers knew how truly close they are (the sharks), I would bet there would be a clamoring for nets at the beaches here!

 

[Theunis]

Interesting; here in S FL - off Key Biscayne - I've flown over the beach numerous times in a helicopter and seen lots of sharks close to the beach - mostly carib. reef sharks.

Never been an attack in that area, however if most beach goers knew how truly close they are (the sharks), I would bet there would be a clamoring for nets at the beaches here!

Thanks for the comments Jupiter31!

My brother and I had a few dives at the Tsitsikamma National Park, South Africa a few years ago. While diving and viewing a few Smooth Hound sharks on the bottom, other holiday-makers were swimming with their ÅÃoogy-boards on the surface totally unaware of us and the sharks. In any case I donÃÕ think those sharks were any threat to the swimmers though!

 

[Parso]

Shark nets are used here in Sydney during the summer months. The nets are randomly moved around from beach to beach. The netting program was introduced in 1937, and as far as I know, in that time, there has only been 1 attack on a netted beach in Sydney, and that occurred a few weeks ago at Bondi Beach. Prior to 1937 there were many attacks. Its pretty hard to argue against statistics like that as far as the effectiveness of the nets are concerned.

Taking all that into account, I would hate to think of the amount of by-catch that has been killed in that time. I know for a fact that dugongs, whales, turtles, rays and dolphins have been caught.I, personally came across an Eagle Ray trapped in a shark net. I untangled it and set it free. I hope it survived.

I would like to see the netting program here abolished. I really can not see it happening though. We had a number of shark related incidents this summer. It would take a very brave government to stop the netting program because if there did happen to be a fatal incident, I'm sure a lot of people would place the blame at the feet of that particular government.

It is a very good question that you ask. You would think that in the 21st century, we would have come up with a more environmentally friendly solution for this problem, not only for the by-catch, but the shark population as well.

Cheers

Parso

 

[Jupiter31]

Good post - agree 100% w/ all your points