Sharks

[LeeToRainesToRoach]

My last shark thread about the 11 people eaten by great white sharks off southern WA between 2010-17 devolved into a shitfight over drum lines and whataboutism, so am starting again here.

This thread isn't intended specifically to deal with attacks, so feel free to discuss personal experiences, documentaries, research or whatever. But I'm going to start with the spate of recent fatals in the Queensland/northern NSW region; the death of a surfer near Grafton today makes four in three months.

6/4/20 - 23yo swimmer at North West Island, approx. 75km off the coast of Gladstone (Q)
7/6/20 - 60yo surfer at Kingscliff, just south of Tweed Heads (NSW)
4/7/20 - 36yo spearfisher at Fraser Island, just off Hervey Bay (Q)
11/7/20 - 15yo surfer at Minnie Water near Grafton (NSW)

The five fatals (including a diver off Esperance in January) makes 2020 the worst year for fatalities since the 1920's and 30's when as many as 10 people were killed annually. Australian protection for the great white and the tiger*, which along with the bull shark make up the maneating "big three", has resulted in elevated risk to beach users.

Edit: a quick Google suggested the tiger shark is protected, which is incorrect.

 

[23.21.159]

Is it possible that more people are out in the water because the virus has limited other potential recreational activities?

 

[Midsy]

My personal attitude is tough luck for beach users.

Those recreational activities come with the very minor risk of shark attack. Want to do the activity, take the risk.

While open to persuasion, I tend to agree with this angle at the moment. I’ve done a lot of beach and open water swimming all around the world and am always looking over my shoulder no matter where I am. I’m in their domain but am generally happy to take the risk.

 

[LeeToRainesToRoach]

New species of ‘walking’ sharks discovered in Australia

Walking sharks sounds like something you’d see in a preview for Sharknado 8: Nowhere Is Safe, but it’s apparently a totally real thing, and researchers have discovered a handful of species in recent years that have seemingly evolved the ability.

Scientists have known about sharks that have the ability to “walk” with their fins on dry land for a while, but in researching the known species they discovered four species that have apparently developed the ability much more recently. The research was published in the journal Marine & Freshwater Research and it suggests that sharks may gain some big advantages by being able to slink along the seafloor rather than swimming.

The walking sharks tend to appear in roughly the same area, which happens to be in the waters off of Northern Australia. They’re typically smaller in size — you won’t spot a great white shark walking along the bottom of the ocean any time soon — and it appears to help the sharks hunt for ground-dwelling prey.

“Instead of swimming around, these little bottom-dwelling sharks actually ‘walk’ using their pectoral and pelvic fins, which makes it easier for them to poke their heads under coral and rocks as they look for small fish, snails and crustaceans to eat,” Mark Erdmann, a co-author of the study, said in an interview. “We’ve found that most walking sharks spend their entire lives on the same reef they where they hatched — never really moving more than a mile out of this radius. The only way they can get across deep water or move a significant distance would be if they are on a reef that is moving due to tectonic plates shifting.”

The researchers explain that the sharks that have been observed walking tend to be in isolated areas and don’t travel far. They attribute the rapid development of walking techniques to individuals or small groups of sharks moving to a new area and, once they adopt the walking technique, future generations learn it from birth.

“Speciation typically happens when individuals of a given species get separated from their main population — sometimes by walking or swimming or being carried away on a current to an isolated place,” Erdmann explains. “If they are lucky enough to survive and breed, eventually evolution will take this new population in a different direction and often leads to a new species.”

The researchers say that intend to study the walking sharks further and learn more about their habits. Walking sharks are still a poorly-understood subset of the shark family tree, so there’s still plenty of questions left to be answered.

 

[HR]

My personal attitude is tough luck for beach users.

Those recreational activities come with the very minor risk of shark attack. Want to do the activity, take the risk.

Yep agree.
Although i will add, we take alot of the fish from the water but are not allowed to take the top predators, we are causing a dierect imbalance which is probably not good for those described above or for the other beings in the oceans.

 

[LeeToRainesToRoach]

Yep agree.
Although i will add, we take alot of the fish from the water but are not allowed to take the top predators, we are causing a dierect imbalance which is probably not good for those described above or for the other beings in the oceans.

Maybe. It's a contentious issue.

Whales are also protected. Big sharks have followed them up and down the coast for aeons.

 

[AngryAnt]

The opposite is true actually. Removing large sharks or any apex predators tends to have bad effects on ecosystems.

 

[tigerdell]

Deleted

 

[DavidSSS]

Yep agree.
Although i will add, we take alot of the fish from the water but are not allowed to take the top predators, we are causing a dierect imbalance which is probably not good for those described above or for the other beings in the oceans.

I think we do take at least some top predators - flake for example?

Might be wrong as I don't eat fish, but I was always told flake was shark.

DS

 

[LeeToRainesToRoach]

I think we do take at least some top predators - flake for example?

Might be wrong as I don't eat fish, but I was always told flake was shark.

It's shark. Officially only gummy shark can be labelled as flake. These aren't apex predators and are commonly eaten by bigger sharks. But it's true that they're overfished. As a result several other shark species have been commonly substituted. There was a crackdown a few years ago and I'm not sure whether it still goes on.

 

[HR]

I think we do take at least some top predators - flake for example?

Might be wrong as I don't eat fish, but I was always told flake was shark.

DS

The west aussies think the vics are weird for eating shark for in WA there are so many choices of very popular fish species.
I have read that vic is one of the biggest purchasers of WA bycatch shark. Not sure how true these days.
As for the whales, we dont target consumption of their food. So are not necessarily stressing their eco system directly as we do for sharks. Point taken about the connection between the 2 though.
There will always be a contrarian POV regarding apex predators, logic tells me and i still consider fishing and sharing in their food chain a stress to their eco system, they still got to eat and if there is less to eat etc etc etc.

 

[Brodders17]

i think humans would be considered apex predators in the sea. and the indiscriminate over fishing that happens world wide may be a factor if shark attacks are truly on the rise.

 

[artball]

Is it possible that more people are out in the water because the virus has limited other potential recreational activities?

to a point.
what it did do was that when certain beaches closed because of Covid, it led people to other beaches that became crowded when normally they were a bit quieter .. much to the chagrin of locals ..

 

[LeeToRainesToRoach]

they still got to eat and if there is less to eat etc etc etc.

Great whites are about 5 feet long at birth. Around 9 feet, their dietary interest changes from ocean fish to meatier prey - pinnipeds including seals etc. These are more likely to be involved in so-called "test bites" on humans. At around 14 feet they don't *smile* around and prey is typically ambushed with a catastrophic bite.

The middle category of GWS is likely to have been involved yesterday. Even then, it moved in a second time to attack which puts the lie to the "they don't like the taste of us" mantra. There are very few rules that hold true for all shark attacks. A hungry shark will bite you, is perhaps the only one.

 

[artball]

This thread isn't intended specifically to deal with attacks, so feel free to discuss personal experiences, documentaries, research or whatever. But I'm going to start with the spate of recent fatals in the Queensland/northern NSW region; the death of a surfer near Grafton today makes four in three months.

here's a stat for you LTRTR - over 300 whites tagged on the far nth coast nsw. mostly between Ballina and Evans Head, a relatively small area. we know they wander, so the guy at Kingscliff and the kid at Wooli fall well into this zone. the other interesting thing is that George Greenough, who has been in the water nearly everyday on the nth coast for 50+ years, is concerned at the rapidly decreasing size of Dolphin Pods south of Cape Byron..

 

[LeeToRainesToRoach]

here's a stat for you LTRTR - over 300 whites tagged on the far nth coast nsw. mostly between Ballina and Evans Head, a relatively small area. we know they wander, so the guy at Kingscliff and the kid at Wooli fall well into this zone. the other interesting thing is that George Greenough, who has been in the water nearly everyday on the nth coast for 50+ years, is concerned at the rapidly decreasing size of Dolphin Pods south of Cape Byron..

Hadn't heard of this guy. Tells a good yarn! He obviously has a lot of experience... generally sharks will prey on young or infirm dolphins, so the implication that they're reducing the numbers of healthy dolphins is interesting. I haven't seen any research of that type, or even heard the theory before, which is not to say it isn't happening.

 

[artball]

Hadn't heard of this guy. Tells a good yarn! He obviously has a lot of experience... generally sharks will prey on young or infirm dolphins, so the implication that they're reducing the numbers of healthy dolphins is interesting. I haven't seen any research of that type, or even heard the theory before, which is not to say it isn't happening.

George hasn't said that the decreasing Dolphin numbers is because of the increasing numbers of Whites, it's just something that appears to be happening simultaneously. Mind you, a lot of the older water men on that part of the coast are calling for a cull of the Whites, which is way out of character.

 

[AngryAnt]

i think humans would be considered apex predators in the sea. and the indiscriminate over fishing that happens world wide may be a factor if shark attacks are truly on the rise.

Humans are a laugh. We are overfishing the oceans and screwing up ecosystems, and the solution is "we need to kill more big sharks to balance this out".

 

[HR]

i think humans would be considered apex predators in the sea. and the indiscriminate over fishing that happens world wide may be a factor if shark attacks are truly on the rise.

Yes fair call, we are the "apex" in most situations, one exception is being in the water with great whites.

We have reasonable rule sets around our commercial and recreational fisheries, its the middle ground for pretty much all fish but the great whites are protected and because of this they will prosper.

Still it is their world so play at your own risk.

 

[LeeToRainesToRoach]

George hasn't said that the decreasing Dolphin numbers is because of the increasing numbers of Whites, it's just something that appears to be happening simultaneously. Mind you, a lot of the older water men on that part of the coast are calling for a cull of the Whites, which is way out of character.

Oh OK. Might be pointing out there are less of them to act as lookouts for surfers.