Ken Bondy
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CA Central Coast - Part II: Shark!!!
Something extraordinary happened on Gary's second dive on Tuesday. I waited topside for him to surface. After about an hour underwater he showed up
at our normal exit point at the foot of the pier, put his camera on the rocks like we always do, stood up in the water and pointed towards the
floating dock saying, "I found a shark and I'm gonna go get him." WTF???
Well he wasn't kidding. He went underwater for a few minutes, and when he came back he had about a four-foot long shark:
I scrambled down the rocky embankment and as Gary laid it on the rocks I saw it take one gasp, the body clearly moved and I saw the gill slits quiver.
It was alive but barely so. Gary told me that he had seen it wedged in the rocks under the floating dock when he started his dive, and it was still
there when he returned after the dive. We hauled it up the bank and laid it on the asphalt in front of the Harbormaster's office.
Obviously it gathered a big crowd. At first we thought it was a young female white, but eventually, along with input from observers, we decided it
was a mako. The tail was very unsymmetrical, the lower caudal lobe much smaller than the upper. With whites the tail lobes are about the same size.
Still not sure about the ID. Any opinions from Nomad biologists (Igor??) Several people said that they had seen the animal swimming on the surface
the previous day, in the bay. Obviously something was seriously wrong with it. The Harbormaster called Fish and Game and they came and retrieved the
shark for an autopsy:
carpe diem!
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Skipjack Joe
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I think it may be a Salmon Shark, Ken.
http://en.wikipedia.org/wiki/Salmon_shark
That would be the south end of their range, though.
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OCEANUS
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Ken
I too thought it was a white when I first looked at the photos. The countershading and face and body all point to a white shark. But the caudal fin of
whites is more symmetrical (homocercal) than that of other sharks like makos (heterocercal).
What makes me agree with your mako ID are the teeth. Mako teeth are slender and pointed throughout the mouth, and tend to portrude like those of the
shark in your photograph. White sharks tend to have teeth that are more broad and triangular. It's possible, that what appears to be a juvenile, could
have a slightly different morphology in its early years than what the adult stage of the fish would have. Perhaps that would explain why this shark,
if it is a mako, does not have that characteristic long, slender, pointy face.
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Skipjack Joe
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Found this short video of Salmon Shark teeth. They're piercing also (like a Mako's), not sawing (like a Great White).
http://www.youtube.com/watch?v=Wy5eefcrYqk
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Ken Bondy
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Possible, Igor. The salmon shark has a "double keel" on the lower lobe of the tail:
"A strong swimmer, it has a wide tail that has a double keel (a second, short ridge running along the upper part of the lower lobe of the tail). A
double keel is unusual among sharks; the only other double-keeled tail is on the closely related porbeagle shark."
I didn't see that on the tail, but then I really wasn't looking for it. It is not apparent in the photo. I have sent photos to a marine biologist
at UCSB who does a lot of ID for us, I will post when she gets back to me.
carpe diem!
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Ken Bondy
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Here are a few more images which might help for an ID:
carpe diem!
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Skipjack Joe
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Yes, I read that as well. But they say it's so much smaller that it's not easily seen. I looked at your pictures and couldn't see it or the dominant
keel.
You probably know by now that just a bit farther north of us this shark is so common that they have charters going out for sportfishing. And many
alaskans fish for them during the summer season (I read it in the forums). But major changes occur at Pt Conception and SoCal people are pretty
unaware of this shark.
The size, shape, coloration, and teeth (even distribution) support this species. We'll see ....
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Skipjack Joe
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| Quote: | Originally posted by Ken Bondy
Here are a few more images which might help for an ID:
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Oh, now I see the top keel quite well. Maybe the bottom one as well.
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Ken Bondy
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Help me Igor, where are they?
carpe diem!
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Skipjack Joe
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In front of the tail fin, along the peduncle, there is a ridge that runs horizontally along the edge of the gray/white color. I believe that is the
dominant keel. It runs all the way back to where the tail fins leaves the tail. If you look at your friend holding the fish it is quite dark on top in
front of the tail. The picture of the fish laying down is white all around that area. I think that's because the raised keel is blocking the dorsal
view that you should be seeing from that angle.
At the very tail there is a much smaller and shorter ridge that looks white because of the direction of the sunlight. That could be the 2nd keel but I
could be reading into it. That is looking and seeing something that I want to be there (like your analysis of my faith, heh).
I believe those are keels based upon the fact that similar structures on jack crevalles and tunas are called keels.
[Edited on 6-22-2012 by Skipjack Joe]
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Ken Bondy
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Igor I think many sharks have that keel. It's actually in the narrowest part of the body just before it meets the tail. I am pretty sure all
Carcharodon sharks have it. I know the white has it, you can clearly see it in my avatar picture. The way I read the description of the salmon shark
there is also a keel in the lower lobe of the caudal fin. That's what makes it a "double keel". I don't see that one in this shark. Maybe I am
misinterpreting all this but it sure isn't obvious to me.
carpe diem!
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Ken Bondy
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Igor here's a blue shark with the same "keel" in the thinnest part of the body just before it meets the tail.
carpe diem!
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Skipjack Joe
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I'm sorry. Try as I might, I can't find a picture of the double-keel on the salmon shark. I guess people are more interested in their teeth and jaws.
My interpretation is that the keel at the very back ends with 2 keels, that is like a forked like keel. It makes no sense to me to have it any other
way on the lower lobe because of it's function. If it was any other way other than horizontal it would impede the fishe's swimming ability, not
enhance it. The bones (excuse me, cartilege) in the lobes all come off at angles to the body and I don't think it would grow from the rays of the
fins.
So, I'm staying with my original proposition that the white area in your image is likely the lower member of the keel.
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Ken Bondy
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Your explanation is very compelling. I don't think I've ever seen a "keel" in either lobe of the caudal fin. OTOH, I've seen MANY keels in the thin
part of the body as it meets the tail. Would be nice to see some pictures. I just heard from my marine biologist friend at UCSB and, surprisingly,
she couldn't ID the shark. She is sending my photos on to a "shark expert" so maybe we will get an ID soon 
carpe diem!
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LancairDriver
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Looks a lot like what fishermen occasionally turn up on the So. Oregon coast. A lot of people thought they were young Great Whites, but the State
Biologists have identified them as Salmon Sharks.
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Ken Bondy
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I just talked with a good friend, Marty Snyderman, who is a professional underwater photographer and an expert on sharks. He confirms the salmon
shark ID. He also said that it is known that they occasionally beach themselves. He walked me through the "keel" thing and it is very subtle but it
is there. You have to blow up the lower caudal lobe in Photoshop to see it but it is there. Mystery solved, thanks for the input Igor and
LancairDriver.
carpe diem!
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Skipjack Joe
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Sure, Ken.
And if you need any explanations on metaphysical matters I'm available as well. 
If it'[s not too much trouble could you please circle the area where you found the keel and repost the picture. I am curious now.
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