Dead Shark Id

[uncoat]

Yeah, yeah this isn't a fossil but I'm sure some of you shark lovers out there will be able to tell me what this one is. I do alot of beach combing here in Oregon and i came across this one a few years back. Unfortunately i was not the first at the scene and the jaws were gone.. This is the only dead shark i have have come across in Oregon i can think of. My first thought was Great White but due to its size maybe Salmon shark? or Grey shark? Sorry for no scale.. its about 4 feet long.

[lordpiney]

looks like a baby white to me. real shame.

[siteseer]

Uncoat,

That looks like a juvenile great white. They are that size and coloring. It looks too heavy in the body to be a mako but a salmon shark might be another possibility.

Yeah, yeah this isn't a fossil but I'm sure some of you shark lovers out there will be able to tell me what this one is. I do alot of beach combing here in Oregon and i came across this one a few years back. Unfortunately i was not the first at the scene and the jaws were gone.. This is the only dead shark i have have come across in Oregon i can think of. My first thought was Great White but due to its size maybe Salmon shark? or Grey shark? Sorry for no scale.. its about 4 feet long.

[uncoat]

Thanks Lordpiney and Siteseer, Yeah its a shame whatever it is.

[Coco]

Hi,

Do you have a pic of the head ? I can't see it (cutting pic).

Coco

[Sharkbyte]

What a shame. :thumbsd:

[Harry Pristis]

Lamnids have a homocercal tail fin. This carcass appears to have a heterocercal tail fin -- not a great white shark tail. The tail fin is the body part least distorted by gases of decomposition and butchering.

A salmon shark, Lamna ditropis, has a second keel on its caudal peduncle; I don't see such a keel.

[Al Dente]

I think it is a Salmon Shark Lamna ditropis

http://www.dfw.state...na_ditropis.jpg

[ckmerlin]

The secondary keel also rules out Porbeagle Shark , it could be a juvenile Mako shark , but whatever it is i agree with what others have said it as a crying shame !!!

[uncoat]

Thanks for the responses everyone. In comparing my photos to the photo provided by Al Dente, the blue to white color matches to the Salmon shark. It dips down between fins and secondary fins. On ckmerlin's photo of the mako for instance, the blue color seems to be in a relatively straight line. In the photo of the tail I posted, you can see a small hole directly above the anus fin. Its possible there was a small second dorsal that what lost/torn out/eaten between the time it died and became beached. Just a thought.

Edited September 6, 2011 by uncoat

[siteseer]

Harry.

The lower lobe of the fin appears to be bent upward which distorts our view of its length.

Jess

Lamnids have a homocercal tail fin. This carcass appears to have a heterocercal tail fin -- not a great white shark tail. The tail fin is the body part least distorted by gases of decomposition and butchering.

A salmon shark, Lamna ditropis, has a second keel on its caudal peduncle; I don't see such a keel.

[Fruitbat]

Even with the lower fin lobe bent upward it would appear that the tail is heterocercal (uneven lobes) which definitely rules out Great White, Mako or Porbeagle. I'll have to pull out my key to sharks (if I can find it) and give this one a shot later.

-Joe

[siteseer]

Monterey Bay Aquarium has had at least one baby great white in captivity over the past ten years. I saw the first one. The lower lobe does look a little more slender and somewhat shorter than the upper lobe judging by a photo postcard I have.

If not a lamnid, what other shark that size and shape could it be? Remember that the location is a good limiting factor. There are few carcharhiniform sharks that size along the Pacific coast particularly as far north as Oregon (rare enough north of Pt. Conception even during an El Nino year). We can rule out hexanchiforms, squaliforms, squatiniforms, pristiophoriforms, heterodontiforms, and orectolobiforms based on the size and tail shape alone. It could only be a lamniform in my opinion.

Breaking down the lamniforms of the area, we can rule out the sand tiger (wrong color and tail shape), goblin shark (wrong snout if nothing else), megamouth (mouth, body, tail), threshers (tail fin totally different), and basking shark (wrong color and body shape and too small even for a juvenile). That leaves the eastern Pacific lamnids which are the great white, two species of mako, and the salmon shark (the porbeagle is not known from the area). The nose seems too short for a mako and the body is too heavy as well. Salmon sharks have that secondary keel and tend to have dark spots/blotches in front of the gills and their undersides. I don't see how it could be anything else other than a baby great white which is in the size range and body shape.

Even with the lower fin lobe bent upward it would appear that the tail is heterocercal (uneven lobes) which definitely rules out Great White, Mako or Porbeagle. I'll have to pull out my key to sharks (if I can find it) and give this one a shot later.

-Joe

[flyguy784]

Just looked up a picture of "the night shark", Carcharhinus signatus. Specifies, common in deeper waters off Alaska. Could have washed in from there.

[flyguy784]

Just looked at additional images, don't think thats it. We'll probably never know.

[sixgill pete]

Just looked up a picture of "the night shark", Carcharhinus signatus. Specifies, common in deeper waters off Alaska. Could have washed in from there.

Everything I have found on C.signatus, points towards an Atlantic species, deep water from North America south to Brazil including the Gulf of Mexico and off of the African Coast. Also the body appeared more slender than the shark in question.

Edited September 7, 2011 by sixgill pete

[Harry Pristis]

It occurs to me that sharks are probably born with distorted tail lobes -- rolled or conmpressed along its body axis. Could this dead shark be a still-born great white with its tail still distorted in the fetal position?

[NelsonFL]

It's probably not a great white, but some of you were throwing around the term juvenile great white pretty lightly. Only a few a few babaies have ever been found and something like this would likely make the news.

[sharkbiteinc]

We will probably never know for sure whether this is a GW or not.

It looks a lot like a juvey GW, however Salmon Sharks have a close resemblence to GWs. For unknown reasons, young Salmon Sharks frequently wash up on beaches along the Pacific coast of North America.

[Harry Pristis]

It's probably not a great white, but some of you were throwing around the term juvenile great white pretty lightly. Only a few a few babaies have ever been found and something like this would likely make the news.

It's true that little is known about GW pups and pupping.

It is faulty logic to ague that this shark can't be a GW pup because someone would have known about it. (Who would have alerted "the news" . . . the fellow who scavenged the jaws?)

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sharkbiteinc

Posted Today, 12:01 PM

We will probably never know for sure whether this is a GW or not.

It looks a lot like a juvey GW, however Salmon Sharks have a close resemblence to GWs. For unknown reasons, young Salmon Sharks frequently wash up on beaches along the Pacific coast of North America.

Salmon shark would be a reasonable guess -- if that species had not already been eliminated as a possibility because of the lack of a secondary keel on the caudal peduncle. This is an exercise in deductive reasoning; you must not ignore evidence that doesn't fit your hypothesis.

I'm not invested in any particular ID of the shark. It seems to me that the best we can do is to eliminate as many possibilities as possible. That would leave us with the best probable identification.

[Al Dente]

Salmon shark would be a reasonable guess -- if that species had not already been eliminated as a possibility because of the lack of a secondary keel on the caudal peduncle.

I don't think the photo is clear enough to eliminate the possibility of a second keel. If you look at this drawing where the second keel is on a salmon shark, you can see that on the dead shark photo, a piece of seaweed is covering the location of where a second keel would be. Also, in all the photos I see online, I can't make out a second keel, maybe because it something that has to be seen up close and at the proper angle.

Here are a couple more examples of stranded salmon sharks from this website: http://homepage.mac....strandings.html

[Harry Pristis]

I don't think the photo is clear enough to eliminate the possibility of a second keel. If you look at this drawing where the second keel is on a salmon shark, you can see that on the dead shark photo, a piece of seaweed is covering the location of where a second keel would be. Also, in all the photos I see online, I can't make out a second keel, maybe because it something that has to be seen up close and at the proper angle.

Here are a couple more examples of stranded salmon sharks from this website: http://homepage.mac....strandings.html

I do understand what you are arguing, 'Al Dente'. . . Maybe there is an invisible secondary keel on the peduncle. But, I do think that 'uncoat' has provided in his third image an excellent view of the peduncle.

That third image shows three strands of seaweed vertically crossing the horizontal primary keel. The image is from an angle which should show any secondary keel, if present. I don't see one; do you?

Here's what I would expect to see on a salmon shark:

[Al Dente]

Here's what I would expect to see on a salmon shark:

Here's a clearer picture of one from this web site: http://www.pelagic.o...almonshark.html

I still think it would be difficult to see unless it was photographed up close with the proper lighting.

[sharkbiteinc]

If you look at the third photograph, it appears that the second keel on its caudal peduncle has been either cut or bitten off. Unfortunately there is not a direct shot of the subject area of the shark, but I would not rule out the potential for a second keel.

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Salmon shark would be a reasonable guess -- if that species had not already been eliminated as a possibility because of the lack of a secondary keel on the caudal peduncle. This is an exercise in deductive reasoning; you must not ignore evidence that doesn't fit your hypothesis.

[siteseer]

Looking at your photos, I would have to reconsider a juvenile mako as a strong possibility as it has the color, the heavy body, and the nose. The tail has uneven lobes too. We should remember that many body features listed in descriptions of sharks are for adults. Juveniles may have different proportions and perhaps coloring. It keeps me from ruling out the salmon shark as the spots/blotches in front of its gills and on the underside may develop as the animal grows (I don't really know) especially after hearing that this species is known to wash up on beaches in the region.

Someone should show the photos to an ichthyologist.

The secondary keel also rules out Porbeagle Shark , it could be a juvenile Mako shark , but whatever it is i agree with what others have said it as a crying shame !!!