Thread: Kayaker and great white shark

I’ve been looking forward to Bunji coming back. Maybe he never left..

"The largest white sharks that have been reliably measured are right around 20 feet, and any larger than this is likely impossible.

Originally Posted by Barry the hunter

"The largest white sharks that have been reliably measured are right around 20 feet, and any larger than this is likely impossible.

Righto - you got me interested enough to question what I've been told seen or learned so I spent a time bracket dipping into the scientific rags about sharks, and whites specifically. This is the paperwork behind what goes on the public facing web pages. Interesting - seems there is a wee bit of discussion about length/size/weight and the general methodology of measuring these critters and estimating weights and lengths specifically. One point for contention seems to be how the tail sits when measuring - if the fish is on the hard and the tail (caudal) is lying flat it's likely to add a foot or more compared to when it's in the upright position as if the fish was swimming. Same if the fish is measured hanging it would seem, the caudal pulls back if the fish is hanging mouth down. There doesn't seem to be much recording of "how" these fish are measured so it tends to throw a bit of a ? for everything...

As far as the maximum length, I found the original report that gives the Google quote copied up there about anything longer than 20ft being likely impossible. The same report lists a few 'reliably measured' specimens that were longer at 23 feet, which Google doesn't mention. DOC's own handout on the things lists the longest reliably measured female at 21 feet. A few other sources list the longest reliably measured one at 19ft, 20ft, and 5.5m which is a smidge over 18 feet. Monterey Bay aquarium comes back at max size of 7m, 23feet. These are all govt agencies, outfits like National Geo or aquariums with research arms. Weight gets even more interesting, most quoting low end max of 2tons up to 2.5metric tons with one at 7500lbs (3.75 US ton).

So buggered if I know, I think the one consensus is there really isn't a consensus apart from these buggers can get BIG. One thing I've learned on the water is there is always the outlier and the exception to the rule when it comes to animals and you are going to find the one that bucks the norm and is either way smaller than it should be or blows the other end of the size chart out as well. I've had a spiny dog on the boat at 1.2m, these are listed commercially at a max of 1.1m. My wife won a rod and reel in a fishing competition a few years back for an 80cm Blue Mackerel, 4.5Kg - simply for it being the biggest one anyone had ever seen and far in excess of the normal max. Kept us in bait for a couple of charters that did. I caught a 10.1Kg Kahawhai at Astrolabe reef on a full size skirted lure, it is still the biggest kahawhai I've seen to date.

As far as the fish I saw on the IPC up north - one possible explanation is a big arse basking shark which is apparently very similar in appearance and does get to a bigger size than the GW's - but we kind of wrote that off at the time as that species is not really common in our waters and we were not in an area that has a lot of reports of that species (being quite a way north of the 39 deg S line below which is considered their prime patch). Never say never though, but the basking is really the only other species that would explain the behaviour shape and size of what we saw.

Originally Posted by No.3

Righto - you got me interested enough to question what I've been told seen or learned so I spent a time bracket dipping into the scientific rags about sharks, and whites specifically. This is the paperwork behind what goes on the public facing web pages. Interesting - seems there is a wee bit of discussion about length/size/weight and the general methodology of measuring these critters and estimating weights and lengths specifically. One point for contention seems to be how the tail sits when measuring - if the fish is on the hard and the tail (caudal) is lying flat it's likely to add a foot or more compared to when it's in the upright position as if the fish was swimming. Same if the fish is measured hanging it would seem, the caudal pulls back if the fish is hanging mouth down. There doesn't seem to be much recording of "how" these fish are measured so it tends to throw a bit of a ? for everything...

As far as the maximum length, I found the original report that gives the Google quote copied up there about anything longer than 20ft being likely impossible. The same report lists a few 'reliably measured' specimens that were longer at 23 feet, which Google doesn't mention. DOC's own handout on the things lists the longest reliably measured female at 21 feet. A few other sources list the longest reliably measured one at 19ft, 20ft, and 5.5m which is a smidge over 18 feet. Monterey Bay aquarium comes back at max size of 7m, 23feet. These are all govt agencies, outfits like National Geo or aquariums with research arms. Weight gets even more interesting, most quoting low end max of 2tons up to 2.5metric tons with one at 7500lbs (3.75 US ton).

So buggered if I know, I think the one consensus is there really isn't a consensus apart from these buggers can get BIG. One thing I've learned on the water is there is always the outlier and the exception to the rule when it comes to animals and you are going to find the one that bucks the norm and is either way smaller than it should be or blows the other end of the size chart out as well. I've had a spiny dog on the boat at 1.2m, these are listed commercially at a max of 1.1m. My wife won a rod and reel in a fishing competition a few years back for an 80cm Blue Mackerel, 4.5Kg - simply for it being the biggest one anyone had ever seen and far in excess of the normal max. Kept us in bait for a couple of charters that did. I caught a 10.1Kg Kahawhai at Astrolabe reef on a full size skirted lure, it is still the biggest kahawhai I've seen to date.

As far as the fish I saw on the IPC up north - one possible explanation is a big arse basking shark which is apparently very similar in appearance and does get to a bigger size than the GW's - but we kind of wrote that off at the time as that species is not really common in our waters and we were not in an area that has a lot of reports of that species (being quite a way north of the 39 deg S line below which is considered their prime patch). Never say never though, but the basking is really the only other species that would explain the behaviour shape and size of what we saw.

We have seen (and one was accidentally caught) Basking sharks in Port underwood / Marlborough sounds in the late 80s/ early 90s.....

Originally Posted by No.3

Righto - you got me interested enough to question what I've been told seen or learned so I spent a time bracket dipping into the scientific rags about sharks, and whites specifically. This is the paperwork behind what goes on the public facing web pages. Interesting - seems there is a wee bit of discussion about length/size/weight and the general methodology of measuring these critters and estimating weights and lengths specifically. One point for contention seems to be how the tail sits when measuring - if the fish is on the hard and the tail (caudal) is lying flat it's likely to add a foot or more compared to when it's in the upright position as if the fish was swimming. Same if the fish is measured hanging it would seem, the caudal pulls back if the fish is hanging mouth down. There doesn't seem to be much recording of "how" these fish are measured so it tends to throw a bit of a ? for everything...

As far as the maximum length, I found the original report that gives the Google quote copied up there about anything longer than 20ft being likely impossible. The same report lists a few 'reliably measured' specimens that were longer at 23 feet, which Google doesn't mention. DOC's own handout on the things lists the longest reliably measured female at 21 feet. A few other sources list the longest reliably measured one at 19ft, 20ft, and 5.5m which is a smidge over 18 feet. Monterey Bay aquarium comes back at max size of 7m, 23feet. These are all govt agencies, outfits like National Geo or aquariums with research arms. Weight gets even more interesting, most quoting low end max of 2tons up to 2.5metric tons with one at 7500lbs (3.75 US ton).

So buggered if I know, I think the one consensus is there really isn't a consensus apart from these buggers can get BIG. One thing I've learned on the water is there is always the outlier and the exception to the rule when it comes to animals and you are going to find the one that bucks the norm and is either way smaller than it should be or blows the other end of the size chart out as well. I've had a spiny dog on the boat at 1.2m, these are listed commercially at a max of 1.1m. My wife won a rod and reel in a fishing competition a few years back for an 80cm Blue Mackerel, 4.5Kg - simply for it being the biggest one anyone had ever seen and far in excess of the normal max. Kept us in bait for a couple of charters that did. I caught a 10.1Kg Kahawhai at Astrolabe reef on a full size skirted lure, it is still the biggest kahawhai I've seen to date.

As far as the fish I saw on the IPC up north - one possible explanation is a big arse basking shark which is apparently very similar in appearance and does get to a bigger size than the GW's - but we kind of wrote that off at the time as that species is not really common in our waters and we were not in an area that has a lot of reports of that species (being quite a way north of the 39 deg S line below which is considered their prime patch). Never say never though, but the basking is really the only other species that would explain the behaviour shape and size of what we saw.

I have an article around here somewhere form the 80s? where a dude in Aussie caught a big one...I think it was Vic Hislop. I am not sure of the length but I thought it said 7m / 2.6 tons 80yr old. But the one thing I do remember from the article was prior to catching it He was in a pub with some american game fisherman who were stoked to have caught a 250kg gamefish and Vic responds ....Cool, I lost a 250kg bait today...heading back out tomorrow.....

With regards to the larger historical / exticnt ones you mentioned, Part of the reason we had Mega fauna and mega flora (dinosaurs etc) was the CO2 in the atmosphere was many times higher than it is today and this caused very rapid growth of flora resulting in ecosystems that could support larger faster growing fauna. And I also know that sharks were present nearly that far back, if not present at that time so it would stand to reason with enough food etc it would be possible for these to grow larger....I dont think there is enough food supply for them to regularly grow that big now, but there is a lot of unexpored ocean so I would never say it could not happen.

Another interesting titbit re sharks and peoples fear of them (unrsaonable?...Maybe) is that there are nearly 300 species of shark...of that about 7 are known maneaters and another 4 or 5 species supected .....(this is older information circa 2000 so may have changed slightly) And those maneater species are mostly due to the fact we are about the same size as their ususal food source....

Originally Posted by Bush Basher

I’ve been looking forward to Bunji coming back. Maybe he never left..

At least some have finally twigged

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Originally Posted by BRADS

At least some have finally twigged

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A long time ago.