Blufin Tuna Photos Suggest Leader Length

[pametfisher]

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A few months ago I caught a Bluefin that ran about 69" and a couple hundred pounds. I had fought the fish for about half an hour. I released the fish but later examined the leader which was about 10' long. At about the 8 1/2 foot point, the leader was worn about halfway through; a 100# mono leader had become a 50# leader. How the leader had worn at a point that was a foot and a half behind the fish was a simple mystery. The leader must have been wrapped around the fish at some point during the fight.

A couple days ago I caught and harvested a 58" fish (photos below). I took some pictures of the fish to record it but learned something about how leaders wrap around fish as I studied the pictures.

As background to understanding the photos: I put the lure in the right corner of the fish's mouth for the photo op., it had been on the left side during the fight. The leader in the photo was just draped there for the shot and is not intended to imply where it was during the fight.

From the photos you can see that this fish ran over the leader as it took its first long run. Then the leader got trapped by the Ventral fin, Pectoral fin and at times on the Anal fin. I've labeled some of the larger marks the leader made on the fish: L1, L2 and L3.

L1 and L2 were most likely made during the fish's first couple of long runs. You can see in Photos 1 & 2 that L1's position is influenced by the Anal fin. Because L1 and L2 are fairly far back, as the fish swam hard the leader must have been shaken back and forth putting extra stress on the connections. (There may even be a mark behind L1.) We all know it's easier to break a line if you jerk it. A spliced leader connection gives extra margin against breaking in this situation.

In Photos 3 & 4 you can see an array of lines emanating from the Ventral fin. In photo 4, L3 appears to be a pair of lines that were made with the line hung on both the Ventral fin and the Pectoral fin. So at the time I was palming the spool, to add extra drag and lift the fish, my leader was hung up on those bony fin protrusions.

I haven't included a diagram of this but the laws of physics suggest that if you hook a fish in the left corner of the mouth, as it swims away from you it will veer slightly to the right to keep swimming forces in balance. That makes it likely that the leader will cross under the fish, as it did in this case. As the leader crosses under the fish, it will be hit by the Caudal (tail) fin and then the Anal fin.

By the time I got the fish within gaff range, the leader had released clear of all the fins, which means it dragged against them at least once at maximum pressure.

My last thought from these photos is that leaders should be the length of the fish PLUS the girth of the fish plus a margin of a foot or so. That means a 10' leader (120") is good for a fish to 80" or 90". I also use a 12' pre-leader made from double-shielded 80# hollow-weave braid in case the 10' casting leader isn't long enough.

Notes:
1. The fish was caught on a Stella 20000FA, although many have been caught on the Penn 950 SSM which is in the photo which has a good 16-18 lb., bottom of spool drag. The equipment list for this fish was OTI 40/60 Tuna Sniper, 20000FA, 60# JB hollow, 100# Jinkai Streamline leader, Shibuki. Initial drag was 18#, longest run about 100 yards, peak drag est. 25 lbs.

2. My guess is that the L3 lines came when the fish was circling directly below the boat. At that point I was pulling straight up with the spool stopped by palming. Without seeing the pictures, I would not have guessed that the line, at that point, went from the left of the fish, down, under and past the Ventral fin, up and past the Pectoral fin, etc. At some point, the fish rolled since when I gaffed it, the line was no longer wrapped.

PF

[paul708]

thanks for the info.
the pics and showing that leader are very helpfull.
good research will help us all fish better.

[ntvinh986]

Originally Posted by paul708

thanks for the info.
the pics and showing that leader are very helpfull.
good research will help us all fish better.

Hi all, I am a new member of forum. Would a newcomer be warmly welcome here? Good day you guys!!!

[flatliner]

ABSOLUTELY!!!!! The more the better! Feel free to post up pics, comments and anything else you may want to !!!

Kevin

[JIG JERK]

THANKS FOR THE INFO AND PHOTOS.

[B Cartlidge]

Damn, you should be a detective! That's some pretty deep analysis...thanks for posting!

Brian
www.pezmachine.com

[Sea Draggin]

Originally Posted by B Cartlidge

Damn, you should be a detective! That's some pretty deep analysis...thanks for posting!

Brian
www.pezmachine.com

Brian,
Hit me up again this year when you guys come back, that is if you are coming. We will do a repeat of last years fun trip. A little wahoo. A little jigging.