Life Cycle and Spearing Technique of Tuna

[Baur]

Does anyone know how long tuna live and at what rate they grow?
Is there a weight/age ratio where you can crudely estimate the tunas age?
I read somewhere the largest bluefins weighing close to a 1000 kg were caught in the med near Sicily - how old would a fish like that be:hmm ?
Ive taken a few shots at tuna that hang around fishfarms in Greece but I never managed to land a big one (>60kg). At times ive seen world record yellowfin cruising below me at 7m but with the 110 euro I was holding at the time didnt dare to spoil the fish for no reason.
Having discovered the allure of the fishfarm I spent quite a few frustrating dives among the giants looking for a small one to shoot:duh.
Im trying to form a definitive approach to the technique of locating, hunting, and landing 100kg+ tuna, and am inviting those with experience to contribute their knowledge in this thread.

 

[Rui_Santos]

Bluefin tuna info

Hi Baur,

Run a search in google with "Thunnus thynnus". You will find lots of info on it.


This is a nice one...
http://www.faocopemed.org/vldocs/0000607/scrs_01_135.pdf

Cheers,
Rui

 

[fer_abella]

Try www.pescasub.com I know all the things you want to know about tunas

I have read almost anything interesting on tunas and I have captured one 278 kg. But I have a thread about it (you can write in english) in this address :

www.pescasub.com

 

[Baur]

Rui

Very comprehensive article for tunas 4-16 yrs (110cm-289cm). It appears that weight is too erratic in tunas to establish a general rule of deriving age, while the spine measurement is more reliable. This is a new concept for me so thanx for the contribution. Still there remains to be seen the age/size ratio for tuna over 289cm (250kg) as well as the life expectancy that would enable bluefin tuna to theoretically reach the 1000kg mark.
Are the age/size patterns in Yellowfin different -assuming they reach smaller proportions-? Could it be that a 100kg yellowfin is older than a 100kg bluefin?

 

[Baur]

Fernando

I heard and read of your achievement and was amazed, along with the rest of the spearfishing community, by your 279kg bluefin. My congratulations on such a magnificent catch. My spanish is very basic and www.pescasub.com although it offers a language option for english speakers does not translate the actual posts. Perhaps if you like you can give your opinion to some of my questions given that you are the most qualified in this forum to do so:

1.What would you consider the best speargun / speargun setup for hunting 100kg+ tuna.

2. How effective are flashers in areas that you know beforehand have increased tuna activity and what type flashers do you think are best.

3. What is the behaviour of large tuna once speared and what do you think are the best contolling tactics.

I Thank you in Advance.

Safe Diving

 

[Rui_Santos]

Baur,

I've never heard of 1000kg bluefin. I've heard of 1000 lbs plus blue fins. In fishbase the max published weight is 684kg and the International Game Fish Association (IGFA) all-tackle record is 1496 lb. (679 kg).
Yellowfins grow up to 200kg to max age of 8 years (fishbase),
so it seems they grow faster than bluefin, if I’m seeing this right,
Blue fin get to 100kg between 7 to 9 years of age.

From another site:
http://www.atuna.com/species/species_datasheets.htm#Northern_bluefin_tuna

"Northern Bluefin tuna makes extensive migrations. It is the slowest growing tuna species, which can reach an age of 20 years or more, which explains her size. Bluefin is extremely popular in Japan for sashimi, due to its large size, color, texture and high fat content of the meat. It's quality in combination with its rarity make it the most expensive tuna species."

I've also found this link with great photos of the "Mattanza" in Italy.

http://www.norbertwu.com/pew/srd/

Cheers,
Rui

 

[Baur]

Rui

Cant come across the exact article on the net as it was in a spearo mag a few years back that I read about a 1000 kg tuna caught in Sicily but the impossibility of that number has been bothering me since:head.

Have been googling and found ranging max weights for bluefin from 42kg rofl to 817 kg (Encarta Encyclopedia), while the accepted average life span is less controversial, at about 20 years.

The "mattanza" is quite impressive. Did not know of this technique they use. Amazing the knowledge the local fishermen have of the tuna runs.

Safe Diving

 

[fer_abella]

Originally posted by Baur
Fernando

I heard and read of your achievement and was amazed, along with the rest of the spearfishing community, by your 279kg bluefin. My congratulations on such a magnificent catch. My spanish is very basic and www.pescasub.com although it offers a language option for english speakers does not translate the actual posts. Perhaps if you like you can give your opinion to some of my questions given that you are the most qualified in this forum to do so:

1.What would you consider the best speargun / speargun setup for hunting 100kg+ tuna.

8 - 9 mm spear, 800 joules energy speargun. Slip tip. 200 liter flotability buoys attached to spear. Big elastic in the middle.

2. How effective are flashers in areas that you know beforehand have increased tuna activity and what type flashers do you think are best.

Chum is the way to attract tuna.


3. What is the behaviour of large tuna once speared and what do you think are the best contolling tactics.

It depends where you shoot it. If it continues to live, will go deeper with very strong pulling power.

Tactics : wait, shoot it to kill it, use something to lift it from the deep.


I Thank you in Advance.

Safe Diving


Where are you going to hunt for them?
What kind of equipment do you have?
Did you see them in the water?

Fernando





Baurzhan Sagdiyev

 

[Baur]

Fernando

I will hunt the tuna in a deepwater bay in greece that has three big fishfarms with bass and sea bream. Tunas are attracted by the fish in the farms and the food that is fed to them and swim around the farm. Workers on the farm actually throw chum in the water and shoot them with a shotgun from the surface. Hunting in the summer months I frequently find bluefin and some times yellowfin of all sizes in these waters, especially in August when the northern winds die down. In this place ive taken a 60 kg bluefin which is my best success sofar.
There is always 3-4 big isolated ones 120-200kg in the bay that become local because of the farms. One will usually come at some point while im doing aspettos or will swim underneath me up to 5-7m but I never shoot because i know I will lose it or will have to cut the shaft loose.

I have just gotten a Totemsub Tahiti 120 with double 16mm bands. Im thinking of equiping double 19mm bands with 8mm threaded sharkfin shaft from Omer and a slip-tip which I have still not chosen. I dont know if this will deliver the 800 joules you mention but tell me what you think.

For a float im thinking of using a 2.3m rib tender that I have without the engine connected as break away to the shaft with motorcycle brake wire for the first meters and then just anchor rope to the tender. When you say "big elastic" do you mean a big bungie or something else?

If I use the rib as a float with a 30-40m in total line to the shaft, do you think I will be able to keep it at that depth so I can deliver the second shot or will it rip itself free because of too much resistance?

If the shot is good but does not kill it or snap the spine does the tuna tire quickly like the amberjack?

Sorry for the long post and thanks for taking the time.

Baur

 

[fer_abella]

Originally posted by Baur
Fernando

I will hunt the tuna in a deepwater bay in greece that has three big fishfarms with bass and sea bream. Tunas are attracted by the fish in the farms and the food that is fed to them and swim around the farm. Workers on the farm actually throw chum in the water and shoot them with a shotgun from the surface. Hunting in the summer months I frequently find bluefin and some times yellowfin of all sizes in these waters, especially in August when the northern winds die down. In this place ive taken a 60 kg bluefin which is my best success sofar.
There is always 3-4 big isolated ones 120-200kg in the bay that become local because of the farms. One will usually come at some point while im doing aspettos or will swim underneath me up to 5-7m but I never shoot because i know I will lose it or will have to cut the shaft loose.

I have just gotten a Totemsub Tahiti 120 with double 16mm bands. Im thinking of equiping double 19mm bands with 8mm threaded sharkfin shaft from Omer and a slip-tip which I have still not chosen. I dont know if this will deliver the 800 joules you mention but tell me what you think.

It will be enough. If you shoot in the head at close distance.

For a float im thinking of using a 2.3m rib tender that I have without the engine connected as break away to the shaft with motorcycle brake wire for the first meters and then just anchor rope to the tender. When you say "big elastic" do you mean a big bungie or something else?

Yes, a big bungie. 2mm stainless steel cable the first 10 meters.

If I use the rib as a float with a 30-40m in total line to the shaft, do you think I will be able to keep it at that depth so I can deliver the second shot or will it rip itself free because of too much resistance?

If the bungie works and the tuna is seriously injured, that will be enough. Anyway I would use a progressive floating device. If you put 6 buoys of 25 liter each, in 3 meter distance between each across the line wiil be better yet.

If the shot is good but does not kill it or snap the spine does the tuna tire quickly like the amberjack?

No. It does not get tired very quicly. It pull strong for a log time with ocasional bursts.

Sorry for the long post and thanks for taking the time.

Baur

 

[tamoshee]

Hi Baur,
Fascinating post, I would love to come and join you for a weeks fishing in August or September if youre interested, good luck with your spearing you're setting your tragets high which is the best way to proceed...

David

 

[Baur]

Fernando

Thank you for your valuable information.

I will modify my setup as you propose and am confident ill get a good chance at landing one of the big ones:martial.

Many successes in the future and safe diving.

Baur

 

[Baur]

David

Thanks for the luck I will definitely need it.

It has become a point of honour with the tunas. Just when I manage to feel some contentment with my spearing, these 150kg torpedos come laughing out of the abyss to remind me that I am not half as good as I think.
Something like my mother-in-law:yack...

If you are going to be anywhere in the Dodecanese islands (include Rhodes, Kos, Simi, Leros, Patmos, Kalymnos) from mid July until late August PM me and we can organise something.

Safe Diving

Baur

 

[Greekman]

hmm....i will be in karpathos for the whole summer

 

[tamoshee]

Sounds possible, last summer I spent 2 weeks in Kos (Kefalos village) late july, spearing every day often twice a day, This year I'm thinking about a week in the Azores and a week in Kos, we'll see how much money I make between now and August!!
Anyhow Baur I will watch your post carefully and try and think of a way of persuading my girlfriend that a return trip to Kos would be wonderfull, I think Ive already convinced her about the Azores so I'm half way there! regards David

 

[Baur]

Excellent. I will be in Kalymnos during that period. If you were in Kefalos you could see Nissiros on the south. In the north is Kalymnos at 18 nautical miles from Kos port so if you want to meet up its a matter of 90 minutes and a phone call. After mid August is best for spearing because during most of July and early August the wind intensity is stupid.

My fishing takes place at dropoffs mostly on east and south Kalymnos (due to persistent n/w wind), on numerous islets and islands in a 40 mile radius, and the occasional trip to the reefs of north Karpathos (listening Greekman?).

What did you think of Kos and Kefalos and the fishing there?

Since you are going to Azores you might want to consider some of Fernandos advice. I heard that the big brother of the bluefin he shot is out looking for revenge .

 

[tamoshee]

Kefalos is a beautifull village but the fishing wasn't great! I looked over at Nysyros every day wondering about fishing there, you can get a tourist boat daily from kefalos harbour, climb the volcano buy some pummice stone and down again (I thought why bother with the volcano, just get in the water!) The water was crystal clear where ever I dived and it was very beautifull, but I always dived from the shore and I never saw anything much over 1Kg. The island in Kamari bay with the little church on it is a beautifull place to swim but the fish disappointing. I went to Liminios (I think thats how you spell it) The fishing looked potentially better but the wind was wild, its on the north of the island! Spearing isn't all about the fish though! However the thought of catching a 20Kg bluefin does appeal greatly, mind you I dont think I would contemplate fishing on the scale of Fernando. I would love to see 100Kg + tuna, but perhaps leave it in peace.

So goodbye for now and perhaps see both you and greekman in late August. Happy spearing (I'll go and check some of the holiday databases for packages to Kalymnos, I think if Im right, the packages and charters fly to Kos and transfer by boat to Kalymnos)

David

 

[Baur]

David

The rule about these islands is that waters that are easily accessible (beaches) are annihilated by the hordes of various spearos. You have to go to as desolate places as possible, prefferebly cliiffs and dropoffs (if you have no boat). Otherwise you are in for a long swim from the beach to locate good sizes. Always have the biggest and reddest float possible because there are many idiot "captains" chucking dynamite in these areas.

Hope you can make it.

Where are you from England?

Baur

 

[tamoshee]

Hi Baur
Yes from England although I spend as much time as possible in India where I do most of my spearing (with more success than in Kos) They use dynamite there also! I guessed that the waters off the main beaches in Kos had been over speared, the fish were very wise! Good tip about the float, I value my hearing. I wil be in contact if I organise something, I have a good feeling about things because my girlfriend loves Kos and would be happy in Kalymnos also I guess, her goal on holiday is to get as brown as possible, although she is now developing an interest in snorkelling and has been out with one of my guns (perhaps more dangerous than the idiot captains)

Catch a big bluefin and get the picture on to the photo forum! bye for now

David

 

[Greekman]

this should be an interesting summer