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Autopsea

Member Since 17 Jan 2008
Offline Last Active Nov 29 2013 03:52 AM
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Posts I've Made

In Topic: Do you think Ocearch really love sharks?

29 November 2013 - 01:54 AM

Acoustic tagging is not the same tool. It's very different and should be complementary when it can be used at all. The reason is that you need recievers to "record" the shark. The range is generally ~200m. You will have 0 information about where is the sharks when he is away from of the those recievers, which make it poorly informative in the case of pelagic/semi-pelagic sharks.

 

It is a great tool for resident sharks however, because it will give you information about the daily routines of sharks. But of no use to learn about long migrations, deep sea uses, etc...

 

edit : hope it don't go controversial but we did a quick recording in 2011 on a grey reef sharks - very easy sharks as they are very robusts.

This is internal accoustic tagging. One could say very invasive but we have over 12 months cool data about their roaming around healthy : )

notice how thick the skin is on females. (and the divers under us at the beginning - if I remember well it was Bill Gates. We had James Cameron the next week ^^)

 


In Topic: Do you think Ocearch really love sharks?

28 November 2013 - 11:53 PM

I realize how glad I am that I'm mostly working with small robust sharks. Harder I've deal with so far are bull sharks that get tired pretty fast - you have to work really fast and make sure you release it is shallow waters in case he needs some help...

 

some tonic immobility before release makes a big difference, they seem to "forget" what just happened and go back very peacefully.

 

 

 

For the question about "do we need to catch GWS to tag them?", I guess it depend on several things including where you are (i.e. how clear is the water, can you approach GWS underwater without too much risk) which make it harder when you are elsewere than at Guadalupe...

 

I think I remember there is great job being done in south Australia / New Zealand with some really cool large boat designed for GWS which allow fast and easy catch and release.


In Topic: Do you think Ocearch really love sharks?

26 November 2013 - 04:12 AM

(BTW, if I remember correctly, the Quensland alone is killing on purpose over 600 tiger sharks a year just so there is less chance that an accident happen.

A illegal fishing vessel with 4 tons of sharks have been taken in new caledonia less than a month ago, and it's not the first time it happens.

and there is more example like that all around. I understand it's important to watch that no organisation is doing bad things, but these hundreeds of deaths should be more in our focus)


In Topic: Do you think Ocearch really love sharks?

26 November 2013 - 01:50 AM

In a perfect world, everyone would understand that sharks need to be let alone, no one would overfish or even fish them, and we would be totally fine no knowing where they go.

 

However, this is not the world we are living in. Sharks are killed. It raises concerns, and politician are listening to both sides :

 

one that say "we are feeding people, making money, paying people to be fishermen, sharks are just fine we still catch a lof of them and when we don't we will stop anyway because it's not gonna be lucrative anymore and then they can recover"

 

and then there is the people that don't want sharks to be killed. I'm one of them, and we have to "counter" the argument made before. We have to make politics understand that what "killing sharks" bring to society is not as important as "not killing sharks" is.

 

In this world, we can't say "look they suffer", or "poor them they die". It just doesn't work. Politics don't care.

 

We have to come up with solid argument and data and prove to politics why, without a doubt, they should trust us more than them.

 

And doing so it happening through science.

 

Now, it does not justify bad methods, and I am not saying that we have to kill a few to save many - I wouldn't do it because we don't know if we are going to save many in the end.

 

I do not comment on the Ocearch as well, I don't know enough about them.

 

What I can say however, it that catching sharks (hooks, nets) is the only way we have to do some sort of science on them. Tagging and genetics, which are used a lot today, both needs catching sharks.

 

Because older scientist have been experienced shark catching, we learned a lot of tricks to make it easier for the sharks. I.e. circled barbless hooks, which species are the less resistants, how to handle a juvenile without hurting him, why you should not drag a heavy shark by the tail on a beach, etc....

 

All this techniques allows, if you follow the rules, to make it less stressfull for the sharks. At least for the "easy" species, you can catch and sample /tag individuals quickly enought to make sure there is no dammage, that he go back in the water just fine, and that he'll be here on his routine the next day.

 

So, I guess the original message was :

 

does Ocearch follow these rules, or do they unecesarly (i.e. for TV / to be cool or whatever) hurt sharks ?

 

rather than "is sharks science a good thing?".

 

Catching a shark can be stressfull for him, but if you do it right he'll be just fine. The only problem is, how "right" do you do it.


In Topic: Wide Angle Lens Recommendation for a Full Frame Canon 6D?

13 September 2013 - 03:02 AM

 My only other thought is that maybe Ikelite changed the 5510.11 port since you last bought it.

 

No : I bought a new one recently, no vignetting as well.

 

(however I do have vignetting when using this one : http://uwcamerastuff...sion_5_dome.htm )

 

maybe it's fine with the 5D2 because the combinaison of everything (housing included) makes it work. It might not be the case for other full frame combo.