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School again!


School again!
Photo Information
Copyright: Alli Hemingway (annagrace) Gold Star Critiquer/Silver Workshop Editor/Gold Note Writer [C: 527 W: 18 N: 851] (2996)
Genre: Animals
Medium: Color
Date Taken: 2006-08-04
Categories: Fish
Camera: Olympus C4000Z
Photo Version: Original Version
Date Submitted: 2006-08-04 16:43
Viewed: 4270
Points: 12
[Note Guidelines] Photographer's Note
Dasyatidae is a family of rays, cartilaginous marine fishes.

Dasyatids are common in tropical coastal waters throughout the world, and there are fresh water species in Asia (Himantura sp.), Africa, and Florida (Dasyatis sabina). Most dasyatids are neither threatened nor endangered. The species of the genera Potamotrygon, Paratrygon, and Plesiotrygon are all endemic to the freshwaters of South America.

Dasyatids swim with a "flying" motion, propelled by motion of their large pectoral fins (commonly referred to as "wings").

Their stinger is a razor-sharp, barbed or serrated cartilaginous spine which grows from the ray's whip-like tail (like a fingernail). It is coated with a toxic venom. This gives them their common name of stingrays, but that name can also be used to refer to any poisonous ray.

Dasyatids do not attack aggressively, or even actively defend themselves. When threatened their primary reaction is to swim away. However, when they are attacked by predators or stepped on, the barbed stinger in their tail is mechanically whipped up, usually into the offending foot; it is also possible, although less likely, to be stung "accidentally" by brushing against the stinger. Contact with the stinger causes local trauma (from the cut itself), pain and swelling from the venom, and possible infection from parts of the stinger left in the wound, as well as from seawater entering the wound. It is possible for ray stings to be fatal if they sever major arteries, are in the chest or pelvic region, or are improperly treated. Their stingers are normally ineffective against their main predator, sharks.

Pain normally lasts up to 48 hours but is most severe in the first 30-60 minutes and may be accompanied by nausea, fatigue, headaches, fever, and chills.


Underside of freshwater ray showing mouthLike other rays, dasyatids are viviparous (bearing live young in "litters" of 5–10). Since their eyes are on top of their head, and their mouths on the bottom, they cannot see their prey, and instead use their sense of smell and electro-receptors similar to those of the shark. They feed primarily on mollusks and crustaceans, as their mouths contain powerful, shell-crushing teeth, or occasionally on smaller fish; rays settle on the bottom while feeding, sometimes leaving only the eyes and tail visible.

http://en.wikipedia.org/wiki/Stingray

I took this photo today at the Georgia Aquarium. The school of rays was amazing to behold. They were in the largest tank in the world; the window was made of acrylic and is two feet thick! I got stung by one of these in Destin, Florida. It necrosed the top of my foot which eventually became a huge ulcer which took months to heal. What fun!
PDP, scottevers7, Janice, sAner, marhowie has marked this note useful
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Critiques [Translate]

  •      
  • PDP Gold Star Critiquer/Gold Star Workshop Editor [C: 2821 W: 344 N: 3779] (11769)
  • [2006-08-04 17:49]

Hi Alli, it's a very interesting shot! The eyes look very spooky! It's a pretty good shot considering it's going through 2 foot of perspex and water. The composition and colours are superb. Very well done.

  • Great 
  • Graal Gold Star Critiquer/Silver Workshop Editor/Silver Note Writer [C: 751 W: 31 N: 20] (5100)
  • [2006-08-05 2:28]

Hi Alli,
good composition, interesting view and note. I like the colours, too. Good work. I like it.
Rgs, Aleksander

Good moprning Alli,
Just time for a very quick visit. Very busy day.
Nice shot. Thanks for posting.
Have a great weekend.

I'll mail you later, when I get home from the footie (new season opener today at Wycombe)

Hi Alli,
A great looking school of Rays. This turned out very well under the conditions. Nice colors and composition. The good thing about Chicago if it is hot is going to the lakefront. Always a nice breeze coming off the water.
Scott

  • Great 
  • Janice Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 3277 W: 148 N: 6163] (18832)
  • [2006-08-12 4:18]

Hi Alli. The rays do look good here swimming in formation in the aquarium. Good job on a hard topic. Well done,
Janice

  • Great 
  • sAner Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1455 W: 74 N: 1426] (4750)
  • [2006-08-12 12:56]

Wow! It looks like they're flying! well executed Ali. The focus is sharp, especially when considering you shot it through glass. Colors are natural. Well done & TFS!

Regards,
Pieter

Hi Alli,
Interesting shot of this group and the comp. is great..
Nice detail and colors, with their shiny eyes a nice effect :) Excellent notes,
Well done and TFS!

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