Northwest Dive Club

My buddy and I dived Cove 2 this evening and on the way back in at about 50' encountered a mature dogfish on the sand (silt) that looked as if he was taking a little cat nap. Has anyone else happened upon 'sleeping' dog fish before? I remember seeing a documentary years ago about sleeping sharks, but if I remember correctly, those sleeping sharks were anomalous

By the way, the vis tonight at Cove 2 was fantasitc! I want to say it was the best I've seen there.

I was at Zees Reef on Monday and saw one on the swim out to the wall that was motionless on the silty bottom. Although motionless, it was awake and alert. I tried not to crowd it's space, but I was close enough that it got up and moved away slowly.

-Ben

A dogfish taking a cat nap? That's funny!

Seth T. wrote:A dogfish taking a cat nap? That's funny!

I was thinking the same thing lol


I have seen Dog Fish doing what I have described to my non diving friends as takeing a nap at Sund Rock but this was also during times of low O2 counts in the canal and I have offten thought it could aslo be described as Slugish behaiver as well

some thing to research a bit more
Do Dog Fish Sleep

Sparky

Thought this bit of info was interesting. This is the documentary I mentioned I had seen years ago.

"In 1969, intrepid free diver Ramon Bravo discovered streamlined sharks apparently sleeping in a cave at Isla Mujeres, off the Yucatan Peninsula. Funded by the National Geographic Society, Eugenie Clark and co-workers traveled to Isla Mujeres in 1972 and 1973 to investigate this unprecedented phenomenon. Their field research revealed the species to be the Caribbean Reef Shark (Carcharhinus perezi) and that the water inside these caves have an unusually high oxygen content and reduced salinity, possibly due to freshwater upwellings from the Mexican mainland. The sharks remained in the caves for hours at a time, actively respiring by pumping water over their gills 20 to 28 times per minute. Clark speculates that the enhanced oxygen content may make breathing easier for the motionless sharks and may produce a narcotic effect the sharks enjoy. Since reduced salinity loosens the grip of skin parasites, Clark has suggested that the sharks may use these caves as 'cleaning stations', allowing shark suckers (remoras) to more effectively remove copepods, leeches, and other ectoparasites."

From: http://www.elasmo-research.org/educatio ... _winks.htm

that is very informative but for meat least it raises a nother question how closely are our Dog Fish related to Reef Sharks

And you know I think I may have seen this documentary not to long a go it sure rings a bell

Sparky

I thouhgt I would resurrect this thread because we got some photos of of dogfish just chilling at the Alki Pipeline during last summer. In fact, on more than one occasion we have been able to touch them without them taking off on us. It is my favorite reason to do night dives at the pipeline, you are practically assured a dogfish encounter.

See the <A href="http://www.theperfectdive.com/DEF-Photo.asp?psID=18" target='_blank'>Dogfish Photo</A>

I've been rammed a couple of times too, i think the light blinds them.

Dogfish have an opening just above and behind their eyes called a spiracle (so do skates) which opens and forces water over their gills when they are at rest.

The spiracle closes and isn't needed (I believe) while they are moving. I think Sixgills have these as well. I know I've seen them just resting on the bottom.

Dogfish have an opening just above and behind their eyes called a spiracle

Yeah, it is pretty clear in the photo i linked to in the post above. I just always called it their nse and thought "that's a funny place for a nostril"...Learned something new today