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Materials
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Caudal Tail Vein
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Tonic Immobilization
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Blood Collection
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Blood Smear
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Before handling the animal for blood collection, gather all the materials you may need. For stingrays and other elasmobranchs, microtainers with lithium heparin (green-topped) are often used due to blood coagulation that occurs with EDTA tubes. Other items needed include appropriate-sized needles (usually 25- or 23-guage) and syringes (3 mL), capillary tubes, slides, clay, gloves, and a sharpie or pencil.
The most common vessel approached for blood collection in the southern stingray is the caudal tail vein (or artery). The vein is located along the ventral mid-line tail.
The image on the left shows a cross section of a southern stingray tail with the tail in dorsal recumbency. The barb (blue arrow) is located near the dorsal tail base. The tail vein (black arrow) is located on the ventral aspect of the cartilage (center of the tail). The pink tissue surrounding the cartilage is muscle. |
With the stingray in dorsal recumbency, isolate the tail (an experienced handler with gloves should restrain if necessary to avoid injury from the barb).
For most southern stingrays a 25- or 23-guage needle with a 3 mL syringe should suffice. With the needle and syringe at an approximate 90-degree angle to the tail, insert the needle through the skin on the ventral mid-line of the tail. Once the needle has penetrated the skin, begin gentle negative pressure. Advance the needle until it hits cartilage and then gently back it off the cartilage. When a flash of blood is noticed, stop advancing or backing off and collect the blood sample until a desired amount is in the syringe. For best results, make a fresh blood smear. |