Another kind of angel....
Jul. 22nd, 2005 12:08 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
senoritafishDP brought this critter in to the lab last week.
This is a Pacific angel shark (Squatina californica). If you watch cable television, you may have seen an ad for a children's magazine called Zoo Books, which starts with some footage of a little shark (probably a swell shark) swimming lazily along, only to be engulfed by a much larger fish that suddenly rears up out of the sand. The predator in that footage was an angel shark. They are ambush predators that bury themselves in sand and rear up to seize their prey in extrusible jaws that can extend several inches in front of the head. This one probably weighed about 15 lbs. and just shy of a meter long. The counter it's lying on is probably about 2 1/2 feet wide.
The business end - can you spot the eye?
Angel face...
These guys do have some teeth; unwary divers and fishermen have often been taken by surprise at just how far they can extend their jaws.
This animal was caught along with a load of sardines and mackerel, but this is a rather rare occurrence, we see bat rays far more often. It will be used in the future to train biologists in fish identification. Angel sharks used to be caught much more often in California when there was a gillnet fishery closer to shore, but that gear was banned in state waters a decade ago by a voter referendum, probably a good thing for the angel sharks. I had no idea angel sharks were so slimy. There was quite a mess to clean up after we put this thing in the freezer.
An interesting thing about the biology of these sharks - some sharks can be aged by looking at their vertebrae, which develop one ring for each year. To manage fisheries, it's very important to know how fast fish grow and how old they are at a certain size. A researcher tried raising some of these guys in the lab to see if that was possible for angel sharks. He discovered that yes they do aquire rings on their vertebrae, but it's totally unrelated to the passage of seasons. Angel sharks add rings according to somatic growth; that is, every time they have a growth spurt for whatever reason, they add a ring.
Once I made Christmas ornaments by making copies of an angel shark drawing from a scientific journal, cutting them out and mounting them on stiff paper, and adding a halo and extending feathers from the pectoral fins. They turned out really cute. I gave them to all my co-workers as Christmas gifts. You know, I never kept any of those for my own tree - I should make another batch! ;)
This is a Pacific angel shark (Squatina californica). If you watch cable television, you may have seen an ad for a children's magazine called Zoo Books, which starts with some footage of a little shark (probably a swell shark) swimming lazily along, only to be engulfed by a much larger fish that suddenly rears up out of the sand. The predator in that footage was an angel shark. They are ambush predators that bury themselves in sand and rear up to seize their prey in extrusible jaws that can extend several inches in front of the head. This one probably weighed about 15 lbs. and just shy of a meter long. The counter it's lying on is probably about 2 1/2 feet wide.
The business end - can you spot the eye?
Angel face...
These guys do have some teeth; unwary divers and fishermen have often been taken by surprise at just how far they can extend their jaws.
This animal was caught along with a load of sardines and mackerel, but this is a rather rare occurrence, we see bat rays far more often. It will be used in the future to train biologists in fish identification. Angel sharks used to be caught much more often in California when there was a gillnet fishery closer to shore, but that gear was banned in state waters a decade ago by a voter referendum, probably a good thing for the angel sharks. I had no idea angel sharks were so slimy. There was quite a mess to clean up after we put this thing in the freezer.
An interesting thing about the biology of these sharks - some sharks can be aged by looking at their vertebrae, which develop one ring for each year. To manage fisheries, it's very important to know how fast fish grow and how old they are at a certain size. A researcher tried raising some of these guys in the lab to see if that was possible for angel sharks. He discovered that yes they do aquire rings on their vertebrae, but it's totally unrelated to the passage of seasons. Angel sharks add rings according to somatic growth; that is, every time they have a growth spurt for whatever reason, they add a ring.
Once I made Christmas ornaments by making copies of an angel shark drawing from a scientific journal, cutting them out and mounting them on stiff paper, and adding a halo and extending feathers from the pectoral fins. They turned out really cute. I gave them to all my co-workers as Christmas gifts. You know, I never kept any of those for my own tree - I should make another batch! ;)
